2012 June 27 Wednesday
Sleep With Music To Remember Melodies

Those of you trying to learn complex classical music pieces should probably listen to the music while sleeping.

EVANSTON, Ill. – Want to nail that tune that you've practiced and practiced? Maybe you should take a nap with the same melody playing during your sleep, new provocative Northwestern University research suggests.

The research grows out of exciting existing evidence that suggests that memories can be reactivated during sleep and storage of them can be strengthened in the process.

In the Northwestern study, research participants learned how to play two artificially generated musical tunes with well-timed key presses. Then while the participants took a 90-minute nap, the researchers presented one of the tunes that had been practiced, but not the other.

I doubt this technique would help if applied to listening to book tapes while you sleep. Though perhaps people with sleep apnea (who wake up often) could take in snippets of text every time they wake up.

But be careful about what you try to use sleep to remember. Sleep helps form memories of distressing images. So stay up too late after a really bad experience you don't want to remember in great detail?

By Randall Parker    2012 June 27 11:03 PM   Entry Permalink | Comments (3)
2011 May 22 Sunday
College Degree 2 Decades After Total Memory Loss

23 years ago Su Meck lost her memories at age 22 from a head trauma.

Consider Su Meck. The 45-year-old homemaker from Gaithersburg graduated Friday from Montgomery College with an associate degree in music. It’s the culmination of a life that, in most senses of the word, began at 22.

So complete retrograde amnesia can happen in real life.

In February 1988, a ceiling fan fell on Meck’s head. The blow erased her memory, and she awoke after a week in a coma with the mental capacity of a young child. She no longer knew her husband or her two baby sons. She barely spoke and could not read or write, walk or eat, dress or drive.

Imagine trying to come back from that. For weeks she could not even form new memories. Even today she learns slowly. So her memory formation circuitry is damaged.

Read the whole thing. Inspiring and yet scary.

By Randall Parker    2011 May 22 09:59 AM   Entry Permalink | Comments (2)
2011 February 08 Tuesday
Memories Stronger For Bad Events That Could Recur

If you think some unpleasantness could happen to you again you are more likely to remember that unpleasantness in detail. So knowledge that you can avoid a recurrence will make it easier for you to forget some painful episode of your life.

WASHINGTON—When people think unpleasant events are over, they remember them as being less painful or annoying than when they expect them to happen again, pointing to the power of expectation to help people brace for the worst, according to studies published by the American Psychological Association.

In a series of eight studies exposing people to annoying noise, subjecting them to tedious computer tasks, or asking them about menstrual pain, participants recalled such events as being significantly more negative if they expected them to happen again soon.

So we've lived thru all sorts of unpleasantness that we have forgotten about. We can remember childhood as better than it was we because we do not expect to be children again. This seems like an argument for rejecting the idea of reincarnation. You are more likely to remember the worst parts of your childhood if you think you are going to be born into a human body again and again and again.

By Randall Parker    2011 February 08 07:15 PM   Entry Permalink | Comments (3)
2011 January 23 Sunday
Practice Memory Retrieval To Learn Faster

Instead of repeatedly rereading the same textbook or other material it is better to get repeatedly tested to enhance memory storage and recall.

Put down those science text books and work at recalling information from memory. That's the shorthand take away message of new research from Purdue University that says practicing memory retrieval boosts science learning far better than elaborate study methods.

"Our view is that learning is not about studying or getting knowledge 'in memory,'" said Purdue psychology professor Jeffrey Karpicke, the lead investigator for the study that appears today in the journal Science. "Learning is about retrieving. So it is important to make retrieval practice an integral part of the learning process."

Educators traditionally rely on learning activities that encourage elaborate study routines and techniques focused on improving the encoding of information into memory. But, when students practice retrieval, they set aside the material they are trying to learn and instead practice calling it to mind.

This is far from the first research report to find this effect. This report just serves as an occasion to promote the wider understanding of this avenue of research.

If you are curious to know more Henry Roediger's Memory Lab at Washington University in St. Louis has done a lot of pioneering work in this area. What amazes and disappoints me is just how slow academia has been to use these research results to change how teaching and learning is done. Every lecture or assignment of reading should be accompanied by immediate tests to enhance memory formation. You can read a couple of papers (PDF) from the Roediger lab to get a feel for this: Generalizing test-enhanced learning from the laboratory to the classroom and The Power of Testing Memory

In the latest study practicing retrieval was found to produce the best memory formation.

In two studies, reported by Karpicke and his colleague, Purdue University psychology student Janell Blunt, a total of 200 students studied texts on topics from different science disciplines. One group engaged in elaborative study using concept maps while a second group practiced retrieval; they read the texts, then put them away and practiced freely recalling concepts from the text.

After an initial study period, both groups recalled about the same amount of information. But when the students returned to the lab a week later to assess their long-term learning, the group that studied by practicing retrieval showed a 50 percent improvement in long-term retention above the group that studied by creating concept maps.

This, despite the students own predictions about how much they would actually remember. "Students do not always know what methods will produce the best learning," said Karpicke in discussing whether students are good at judging the success of their study habits.

I've read in previous reports the idea that there are ideal time intervals between times to get repeatedly tested for the same material. However, I did not try testing myself about the details of those time intervals and so now I can't recall the details for you.

By Randall Parker    2011 January 23 10:49 PM   Entry Permalink | Comments (1)
2010 September 23 Thursday
Easier Way To Do Perceptual Learning

Learning musical pitch discrimination can be done with half the effort.

EVANSTON, Ill. --- Scientists long have recognized that many perceptual skills important for language comprehension and reading can be enhanced through practice. Now research from Northwestern University suggests a new way of training that could reduce by at least half the effort previously thought necessary to make learning gains.

The research also may be the first behavioral demonstration of metaplasticity -- the idea that experiences that on their own do not generate learning can influence how effective later experiences are at generating learning.

"Prior to our work much of the research into perceptual learning could be summed up as 'no pain, no gain,'" says Beverly Wright, first author of a study in the Sept. 22 Journal of Neuroscience and communication sciences and disorders professor at Northwestern. "Our work suggests that you can have the same gain in learning with substantially less pain."

20 minutes of training followed by 20 minutes of listening to a musical tone was just as effective as 40 minutes of training. Click thru and read the details.

But the Northwestern researchers found that robust learning occurred when they combined periods of practice that alone were too brief to cause learning with periods of mere exposure to perceptual stimuli. "To our surprise, we found that two 'wrongs' actually can make a right when it comes to perceptual learning," says Wright.

What's more, they found that the combination led to perceptual learning gains that were equal to the learning gains made by participants who performed twice as much continuous task training (training which by nature of its repetition and length often is onerous).

The whole area of optimal training time, optimal exposure time, and intervals between quizzes to help consolidate learning holds out the potential for faster learning with less effort to form longer lasting memories and skills.

By Randall Parker    2010 September 23 10:14 PM   Entry Permalink | Comments (2)
2010 September 12 Sunday
Best Ways To Enhance Learning?

Benedict Carey of the New York Times surveys what is known about techniques for enhanced learning. Varying your study locations is cited as a technique which has been confirmed by much research.

For instance, instead of sticking to one study location, simply alternating the room where a person studies improves retention. So does studying distinct but related skills or concepts in one sitting, rather than focusing intensely on a single thing.

“We have known these principles for some time, and it’s intriguing that schools don’t pick them up, or that people don’t learn them by trial and error,” said Robert A. Bjork, a psychologist at the University of California, Los Angeles. “Instead, we walk around with all sorts of unexamined beliefs about what works that are mistaken.”

Carey mentions other techniques including varying how many kinds of things you learn at one setting.

Curiously, a new report in Science finds the opposite result about learning environments: evidence that varying learning conditions does not help to enhance learning.

The researchers conducted three studies at Beijing Normal University in which subjects were shown different sets of photographs or words multiple times in different orders. The scientists recorded subjects' brain activity while they studied the material. They were asked to recall or recognize those items between 30 minutes and six hours later, in order to test the decades-old "encoding variability theory."

That theory suggests people will remember something more effectively — the name of the third President of the United States, for example — if they study it at different times in different contexts — a dorm room, the library, a coffee shop — than if they review it several times in one sitting. The different sensory experiences will give the brain various reminders of that information and multiple routes to access Thomas Jefferson's identity.

Based on that theory, Poldrack and his colleagues predicted subjects would retain memories of the photos or words more effectively if their brains were activated in different ways while studying that information multiple times.

Instead, the scientists found the subjects' memories were better when their pattern of brain activity was more similar across the different study episodes.

The researchers say they haven't disproven the theory that Carey reports is well established.

The Times piece also quotes the accomplished Washington U of St. Louis memory researcher Henry Roediger about the value of testing and time intervals between learning and recall. I've covered Roediger's research and think it quite valuable.

Educational institutions really ought to take Roediger's results and use them to revamp the presentation and testing of materials that students are meant to learn. Students need access to practice tests that pop up an optimal number of days after they first get taught some material. Also, it might make sense to present more material near the beginning of a course in order to provide more time for the brain to go thru optimal cycle times for learning followed by retrieval to enhance memory consolidation.

By Randall Parker    2010 September 12 11:39 AM   Entry Permalink | Comments (4)
2010 August 04 Wednesday
Ways Of Daydreaming Change Memory Retention

Choose your daydreams about old memories carefully in order to optimize remembering of recent events. You can also choose your memory recall daydreams to help you forget.

When your mind drifts, it's hard to remember what was going on before you stopped paying attention. Now a new study has found that the effect is stronger when your mind drifts farther – to memories of an overseas vacation instead of a domestic trip, for example, or a memory in the more distant past.

Daydreaming at all impairs remembering what you are doing. So in the middle of your work day if you are trying to keep track of a lot of facts in a problem or task avoid thinking about who you seduced when you were a foreign exchange student in college.

Psychologists have known for a while that context is important to remembering. If you leave the place where a memory was made – its context – it will be harder for you to recall the memory. Previous studies had also found that thinking about something else – daydreaming or mind-wandering – blocks access to memories of the recent past. Psychological scientists Peter F. Delaney and Lili Sahakyan of the University of North Carolina at Greensboro and Colleen M. Kelley and Carissa A. Zimmerman of Florida State University wanted to know if the content of your daydreams affects your ability to access a recently-acquired memory.

For one experiment, each participant looked at a list of words as they appeared on a computer screen, one at a time. Then they were told to think either about home – where they'd been that morning – or about their parents' house – where they hadn't been in several weeks. Next, the participant was shown a second list of words. At the end of the test, they had to recall as many of the words from the two lists as possible. Participants who had thought about the place they'd been only a few hours before remembered more of the words from the first list than did participants who had thought back several weeks. The same was true for memories about place, tested in a second experiment. Those who thought about a vacation within the U.S. remembered more words than those who thought about a vacation abroad. The study is published in Psychological Science, a journal of the Association for Psychological Science.

Remember an event from a distant country in the distant past when you want to forget something that just happened.

One practical application of the research might be for people who want to forget about something. "If there's something you don't feel like thinking about, you're better off remembering a more distant event than a close event, to try to put it out of your mind for a while," says Delaney. "It can help you feel like you're in a different situation."

What I'd like to know: Does daydreaming about a total fantasy that hasn't happened do as much to interrupt memory formation as memory recall of older memories does? Is fantasy as disruptive as going down memory lane?

By Randall Parker    2010 August 04 07:14 PM   Entry Permalink | Comments (0)
2009 November 10 Tuesday
Receptor Controls Long Term Memory Formation

A drug that turns off the nogo receptor 1 blocks long term memory formation in mice. Imagine a drug that did the same thing in humans. It would have all sorts of uses and abuses.

Researchers at Karolinska Institutet have discovered a mechanism that controls the brain's ability to create lasting memories. In experiments on genetically manipulated mice, they were able to switch on and off the animals' ability to form lasting memories by adding a substance to their drinking water. The findings, which are published in the scientific journal PNAS, are of potential significance to the future treatment of Alzheimer's and stroke.

It seems likely that drugs which block long term memory formation will be found. Criminals could use these drugs for all sorts of purposes. Commit a crime, force every witness (or victim) to down a drug (preferably liquid so they can't throw up to get it out of them), and then leave.

But then James Bond would get a gene therapy treatment that renders his nogo receptor 1 immune to the known memory blocker drugs.

A research team at Karolinska Institutet has now discovered that signalling via a receptor molecule called nogo receptor 1 (NgR1) in the nerve membrane plays a key part in this process. When nerve cells are activated, the gene for NgR1 is switched off, and the team suspected that this inactivation might be important in the creation of long-term memories. To test this hypothesis they created mice with an extra NgR1 gene that could remain active even when the normal NgR1 was switched off.

Technology enables competitions, struggles, and fights to take place at a higher level. In the long term will technology make society more or less stable?

By Randall Parker    2009 November 10 06:40 AM   Entry Permalink | Comments (4)
2009 June 14 Sunday
Sleeping Soon After Emotionally Salient Learning Improves Memory Formation

Yet another study pointing to the importance of sleep for new memory formation.

WESTCHESTER, Ill. – According to a research abstract that will be presented on Thursday, June11, at SLEEP 2009, the 23rd Annual Meeting of the Associated Professional Sleep Societies, sleep selectively preservers memories that are emotionally salient and relevant to future goals when sleep follows soon after learning. Effects persist for as long as four months after the memory is created.

Results indicate that the sleeping brain seems to calculate what is most important about an experience and selects only what is adaptive for consolidation and long term storage. Across long delays of 24 hours, or even three–to-four months, sleeping soon after learning preserved the trade-off (compared to waiting an entire day before going to sleep).

According to lead author, Jessica Payne, PhD, of Harvard Medical School in Boston MA, It was surprising that in addition to seeing the enhancement of negative memories over neutral scenes, there was also selectivity within the emotional scenes themselves, with sleep only consolidating what is most relevant, adaptive and useful about the scenes. It was even more surprising that this selectivity lasted for a full day and even months later if sleep came soon after learning.

Click thru and read the details. In a nutshell: you are better off learning things between 7 and 9 PM (since that is closer to when you fall asleep) than between 9 and 11 AM.

Payne said that sleep is beneficial for memory and that we remember things best when we 'stagger' our learning episodes across time.

Another study found that if you learn one task and then take a nap before learning a second task that you'll learn faster. You are better off consolidating your learning on one subject before moving on to another subject.

Quality of sleep matters. A study on rats found that slow wave and rapid eye movement (REM) sleep are needed for memory consolidation. There's an aging angle to sleep and memory formation. Old people generally do not sleep as soundly. Well, poor sleep quality impairs memory formation in aging rats. One more reason we need rejuvenation therapies.

My advice: move your learning tasks to the end of the day. Read the technical book or do practice on some skill before bed time. If you can manage to do naps then learn and do mental exercises before napping.

By Randall Parker    2009 June 14 01:28 PM   Entry Permalink | Comments (1)
2009 February 26 Thursday
Doodling While Listening Improves Memory Recall

News you can use. A Yankee Doodle Dandy has a good memory. Who knew?

Doodling while listening can help with remembering details, rather than implying that the mind is wandering as is the common perception. According to a study published today in the journal Applied Cognitive Psychology, subjects given a doodling task while listening to a dull phone message had a 29% improved recall compared to their non-doodling counterparts.

40 members of the research panel of the Medical Research Council's Cognition and Brain Sciences Unit in Cambridge were asked to listen to a two and a half minute tape giving several names of people and places, and were told to write down only the names of people going to a party. 20 of the participants were asked to shade in shapes on a piece of paper at the same time, but paying no attention to neatness. Participants were not asked to doodle naturally so that they would not become self-conscious. None of the participants were told it was a memory test.

After the tape had finished, all participants in the study were asked to recall the eight names of the party-goers which they were asked to write down, as well as eight additional place names which were included as incidental information. The doodlers recalled on average 7.5 names of people and places compared to only 5.8 by the non-doodlers.

Doodle proudly.

By Randall Parker    2009 February 26 11:30 PM   Entry Permalink | Comments (0)
2009 February 06 Friday
Negative Emotions Decrease Memory Accuracy?

Cornell University professors Valerie Reyna and Charles Brainerd find that people do a poorer job of remembering negative experiences.

"You may not remember the specifics of what happened to you, but boy, do you remember it was negative," said Brainerd. "And that allows you to fill in the blanks with 'memories' of negative events that didn't really happen."

Brainerd is the lead author of a study published in Psychological Science (Vol. 19, No. 9); co-authors include his wife, Valerie Reyna, also a Cornell professor of human development, and colleagues from Brazilian universities.

The researchers conducted experiments in which about 120 participants -- half in Brazil and half in the United States -- were asked to read lists of words that had either positive, negative or neutral connotations. They were then asked to identify which words had been listed. When remembering negative words -- such as mad, sad, rage, temper, ire and wrath -- they were much more likely to be inaccurate and "falsely remember" such unlisted words as anger. When identifying positive words, their memories were much more accurate.

The findings challenge traditional ideas about how emotion affects memory, Brainerd says. "Historically the belief has been that negative events are really pretty easy to remember, that negative emotion creates very distinctive memories. What we found was exactly the opposite. Negative information really tends to distort your memory."

This might mean that witnesses to crimes are memory-impaired. Well, if you witness a crime try not to feel unhappy about it and write up your memories while they are still fresh. Do not trust your memories.

By Randall Parker    2009 February 06 08:25 PM   Entry Permalink | Comments (1)
2009 January 28 Wednesday
New Memory Neurons Get Timestamped?

I picture an intelligence agency changing some guy's memory timestamps so he thinks a whole year has gone by.

LA JOLLA, CA—"Remember when…?" is how many a wistful trip down memory lane begins. But just how the brain keeps tabs on what happened and when is still a matter of speculation. A computational model developed by scientists at the Salk Institute for Biological Studies now suggests that newborn brain cells—generated by the thousands each day—add a time-related code, which is unique to memories formed around the same time.

"By labeling contemporary events as similar, new neurons allow us to recall events from a certain period," speculates Fred H. Gage, Ph.D., a professor in the Laboratory for Genetics, who led the study published in the Jan. 29, 2009, issue of the journal Neuron. Unlike the kind of time stamp found on digital photographs, however, the neuronal time code only provides relative time.

Lots of relative and absolute timestamps get used inside software. Incoming packets from a communications bus get timestamped as they come into a box. I write code that does this sort of thing. If neurons turn out to do the same thing this'll be very interesting. There's nothing new under the sun and all that.

By Randall Parker    2009 January 28 10:05 PM   Entry Permalink | Comments (1)
2009 January 27 Tuesday
Different Parts Of Brain Store Older And Newer Memories

Your memories move around.

"It has long been known that older memories are more resistant to hippocampal damage than newer memories, and this was thought to reflect the fact that the hippocampus becomes less involved in remembering as a memory gets older," said Russell Poldrack, PhD, an expert on the cognitive and neural mechanisms of memory at the University of California, Los Angeles, who was not involved in the study. "However, there has been a recent debate over whether the hippocampus ever really stops being involved, even for older memories," Poldrack said.

To address this debate, Christine Smith, PhD, and Larry Squire, PhD, at the University of California, San Diego and the San Diego VA Medical Center, imaged study participants as they answered 160 questions about news events that occurred over the past 30 years. The hippocampus and related brain structures were most active when recalling recent events. Hippocampal activity gradually declined as participants recalled events that were 1-12 years old and remained low when they recalled events that were 13-30 years old.

In contrast, Smith and Squire found the opposite pattern of activity in frontal, temporal, and parietal cortices. In these brain regions — which are located at the surface of the brain — activity increased with the age of the news event recalled. "Our findings support the idea that these cortical regions are the ultimate repositories for long-term memory," Smith said. The researchers found that brain activity was unrelated to the richness of memories or to the recollection of personal events related to the tested news events.

Imagine a future time when we understand brain memory storage well enough to hook in artificial memory extenders.

By Randall Parker    2009 January 27 11:26 PM   Entry Permalink | Comments (0)
2008 October 25 Saturday
Sleep Deprivation Enhances False Memory Retrieval

In a Plos One paper some Swiss and German researchers report in a paper entitled Sleep Loss Produces False Memories that sleep deprivation at time of retrieval enhanced false memories. Don't trust your memories when you are tired. Caffeine prevents the inaccurate retrievals.

People sometimes claim with high confidence to remember events that in fact never happened, typically due to strong semantic associations with actually encoded events. Sleep is known to provide optimal neurobiological conditions for consolidation of memories for long-term storage, whereas sleep deprivation acutely impairs retrieval of stored memories. Here, focusing on the role of sleep-related memory processes, we tested whether false memories can be created (a) as enduring memory representations due to a consolidation-associated reorganization of new memory representations during post-learning sleep and/or (b) as an acute retrieval-related phenomenon induced by sleep deprivation at memory testing. According to the Deese, Roediger, McDermott (DRM) false memory paradigm, subjects learned lists of semantically associated words (e.g., “night”, “dark”, “coal”,…), lacking the strongest common associate or theme word (here: “black”). Subjects either slept or stayed awake immediately after learning, and they were either sleep deprived or not at recognition testing 9, 33, or 44 hours after learning. Sleep deprivation at retrieval, but not sleep following learning, critically enhanced false memories of theme words. This effect was abolished by caffeine administration prior to retrieval, indicating that adenosinergic mechanisms can contribute to the generation of false memories associated with sleep loss.

Researchers at the Washington University Memory Lab have shown that to optimize learning it is better to be tested on material than to study material a second time. Retrieval enhances memory consolidation. Also, there are optimal intervals for retesting. Well, my guess is that if you try to get tested when you are tired you'll not just recall less correctly then but also reduce the accuracy of future attempts to recall the same material. So sleep well before getting tested.

By Randall Parker    2008 October 25 10:11 PM   Entry Permalink | Comments (5)
2008 October 23 Thursday
Selective Memory Loss Possible With Protein In Mice

At least in mice overexpression of protein αCaMKII while recalling a memory causes the extinction of that memory.

Dr. Tsien's research team, in collaboration with scientists at East China Normal University in Shanghai, were able to eliminate new and old memories alike by over-expressing a protein critical to brain cell communication just as the memory was recalled, according to research featured on the cover of the Oct. 23 issue of Neuron.

Dr. Tsien had already created a mouse that couldn't form memories by eliminating the NMDA receptor, which receives messages from other neurons. He then garnered international acclaim by making "Doogie," a smart mouse in which a subunit of the NMDA receptor is over-expressed. Younger brains have higher amounts of this NR2B subunit which leaves communication channels between brain cells open longer. That is why young people can learn faster than older adults.

This time he was examining downstream cascades of the NMDA receptor to learn more about memory formation. An abundant protein found only in the brain, called αCaMKII, was a logical place to look because it's a major signaling molecule for the NMDA receptor. He found that when he over-expressed αCaMKII while a memory was being recalled, that single memory was eliminated.

While some might want to suppress traumatic haunting memories consider the mischief possible by suppressing memories. A government that no longer trusts a secret agent might want to suppress the memories of that agent before firing him. This brings to mind Tommy Lee Jones' character retiring to a post office without his memories. All those people in Men In Black who had their memories suppressed with a neuralizer might some day have real world equivalents.

By Randall Parker    2008 October 23 12:37 AM   Entry Permalink | Comments (3)
2008 July 29 Tuesday
Oxytocin Enhances Your Ability To Remember Happy Smiling Faces

Smile and the whole world smiles with you - especially if they are on oxytocin.

Philadelphia, PA, July 28, 2008 – Oxytocin was originally studied as the "milk let-down factor," i.e., a hormone that was necessary for breast-feeding. However, there is increasing evidence that this hormone also plays an important role in social bonding and maternal behaviors. A new study scheduled for publication in the August 1st issue of Biological Psychiatry now shows that one way oxytocin promotes social affiliation in humans is by enhancing the encoding of positive social memories.

Adam J. Guastella, Ph.D. and his colleagues sought to evaluate the effects of oxytocin on the encoding and recognition of faces in humans. They recruited healthy male volunteers and in a double-blind, randomized design, administered either oxytocin or a placebo. They then presented a series of happy, angry and neutral human faces to the volunteers on a computer screen. Participants returned the following day where they were presented with a collection of faces and asked to distinguish the new faces from ones that they saw on the prior day. The results revealed that those who received oxytocin were more likely to remember the happy faces they had seen previously, more so than the angry and neutral faces.

Dr. Guastella notes that the "findings are exciting because they show for the first time that oxytocin facilitates the encoding of positive social information over social information that is either neutral or negative." John H. Krystal, M.D., Editor of Biological Psychiatry and affiliated with both Yale University School of Medicine and the VA Connecticut Healthcare System, comments on the findings: "The findings from Guastella and colleagues provide new evidence about a chemical system in the body that may help us to connect socially to other people. One could imagine that our ability to recall a particularly happy face at the end of a day full of social contacts could reflect an action of oxytocin."

Social isolation can be a feature of several psychiatric disorders. The success of oxytocin in enhancing positive social memories raises the possibility that oxytocin, or drugs that might act like oxytocin in the brain, could be used to help people who are socially isolated and have difficulty making social connections. Future research will be needed to test this hypothesis.

Some people think they are in rational control. Their emotions are happy to fool them. Our emotions are an invisible puppeteer.

By Randall Parker    2008 July 29 11:48 PM   Entry Permalink | Comments (0)
2007 November 07 Wednesday
Trust Your Medial Temporal Lobe Memories

"Your honor, I swear my memory of this business deal comes from my medial temporal lobe." Trust your memories from the medial temporal lobe (MTL) of your brain but don't get fooled by your frontal parietal network (FPN).

Cabeza wanted to understand why someone could have such strong feelings of confidence about false memories. In his experiments, he scanned the brains of healthy volunteers with functional MRI as they took well-established tests of memory and false memory. Functional MRI is an imaging technique that shows what areas of the brain are used during specific mental tasks.

During the brain scans, Cabeza found that volunteers who were highly confident in memories that were indeed true showed increased activity in the fact-oriented MTL region.

“This would make sense, because the MTL, with its wealth of specific details, would make the memory seem more vivid,” Cabeza said. “For example, thinking about your breakfast this morning, you remember what you had, the taste of the food, the people you were with. The added richness of these details makes one more confident about the memory’s truth.”

On the other hand, volunteers who showed high confidence in memories that turned out to be false exhibited increased activity in the impressionistic FPN. The people drawing from this area of the brain recalled the gist or general idea of the event, and while they felt confident about their memories, they were often mistaken, since they could not recall the details of the memory.

Imagine a witness being grilled while under a functional MRI brain scan device that tells whether answers to questons are coming from memories recalled from a reliable part of the brain.

By Randall Parker    2007 November 07 11:24 PM   Entry Permalink | Comments (1)
2007 September 07 Friday
Repeated Drills To Learn Material Should Be Spread Over Time

Do not overdrill on the same material over a short period of time.

Consider “overlearning.” That’s the term learning specialists use for studying material immediately after you’ve mastered it. Say you’re studying new vocabulary words, flash-card style, and you finally run through the whole list error-free; any study beyond that point is overlearning. Is this just a waste of valuable time, or does this extra effort embed the new memory for the long haul"

University of South Florida psychologist Doug Rohrer decided to explore this question scientifically. Working with Hal Pashler of the University of California, San Diego, he had two groups of students study new vocabulary in different ways. One group ran through the list five times; these students got a perfect score no more than once. The others kept drilling, for a total of ten trials; with this extra effort, the students had at least three perfect run-throughs. Then the psychologists tested all the students, some one week later and others four weeks later.

The results were interesting. For students who took the test a week later, those who had done the extra drilling performed better. But this benefit of overlearning completely disappeared by four weeks. In other words, if students are interested in learning that lasts, that extra effort is really a waste. They should instead spend this time looking at material from last week or last month or even last year.

In other words, as reported in the August issue of Current Directions in Psychological Science, “massing” all the study on a single topic into a single session reduces long-term retention. It’s better to leave it alone for a while and then return to it. Rohrer and Pashler also wanted to see if the duration of study breaks might make a difference in learning. It did. When two study sessions were separated by breaks ranging from five minutes to six months, with a final test given six months later, students did much better if their break lasted at least a month. So, rather than distribute their study of some material across just a few days, as millions of school children do when given a different list of vocabulary or spelling words each week, students would be better off seeing the same words throughout the school year.

All these experiments involved rote learning, but Rohrer and Pashler have also found similar effects with more abstract learning, like math. This is particularly troubling, the psychologists say, because most mathematics textbooks today are organized to encourage both overlearning and massing. So students end up working 20 problems on the same concept (which they learned earlier that day) when they should be working 20 problems drawn from different lessons learned since the beginning of the school year. In brief, students are wasting a lot of precious learning time.

Try to learn something a few times and then set it down and come back and try it again a few weeks later and do that again and again.

I see this as yet another reason why college lectures should all be recorded. You could watch all the material for semester in a single marathon session of a few days. Then watch all the material for another semester the next week and so on. Then eventually cycle back through and watch it all over again a month later.

By Randall Parker    2007 September 07 01:01 AM   Entry Permalink | Comments (6)
2007 May 23 Wednesday
Newest Brain Neurons Learn More Easily

New neurons continually formed in the brain from neural stem cells are more plastic and probably enhance learning abilities.

The steady formation of new brain cells in adults may represent more than merely a patching up of aging brains, a new study has shown. The new adult brain cells may serve to give the adult brain the same kind of learning ability that young brains have while still allowing the existing, mature circuitry to maintain stability.

These results are good news for the future of rejuvenation therapies. The development of replacement youthful neural stem cells to replace aging neural stem cells will likely boost learning ability in aging minds.

The brain is going to be the hardest organ to rejuvenation because most of it will need to be repaired rather than replaced. Replacement using stem cells will become possible before repair using gene therapy and nano repair robots.

Newly formed nerve cells behave in a more youthful manner than cells that have been neurons for longer periods of time.

Hongjun Song and colleagues reported their findings in the May 24, 2007 issue of the journal Neuron, published by Cell Press.

In their experiments, they used a virus to selectively label new brain cells with a fluorescent protein in the hippocampus, a major brain center for learning and memory, of adult mice.

The researchers then analyzed the electrophysiological properties of the new neurons at different times after their formation. This analysis enabled them to measure how adaptable, or "plastic," the brain cells were.

The researchers found that the new adult neurons showed a pattern of changing plasticity very similar to that seen in brain cells in newborn animals. That is, the new adult brain cells showed a "critical period" in which they were highly plastic before they settled into the less plastic properties of mature brain cells. In newborn animals, such a critical period enables an important, early burst of wiring of new brain circuitry with experience.

What’s more, the researchers’ molecular analysis showed that the plasticity of new adult neurons depended on the function of one of the same types of receptors that is associated with learning-related processes in newborn animals. Such receptors are the receiving stations for chemical signals called neurotransmitters, launched from neighboring neurons to trigger a nerve impulse in the receiving neurons. Subtle alterations in receptor populations are the means by which the brain wires the preferred pathways in the process of learning and memory.

Part of the loss of plasticity is probably due to age. But some of the loss of plasticity might be by program. Once a neuron has been around for a while it has probably found some purpose and there's probably a bias in the brain's design against letting a neuron too easily get reprogrammed for other purposes.

By Randall Parker    2007 May 23 10:37 PM   Entry Permalink | Comments (8)
2007 April 01 Sunday
Trade-Off Between Working Memory And Memory Formation?

Blocking neurogenesis helped mice better use recently acquired information still in working memory.

NEW YORK – New research from Columbia University Medical Center may explain why people who are able to easily and accurately recall historical dates or long-ago events, may have a harder time with word recall or remembering the day’s current events. They may have too much memory – making it harder to filter out information and increasing the time it takes for new short-term memories to be processed and stored.

Published in the Proceedings of the National Academy of Sciences (March 13, 2007 issue), the research reinforces the old adage that too much of anything – even something good for you – can actually be detrimental. In this case, the good thing is the growth of new neurons, a process called neurogenesis, in the hippocampus, the region of the brain responsible for learning and memory.

I just had a conversation with a neuroscientist about neurogenesis and memory formation. He downplayed the need for neurogenesis to form at least some types of memories. A lot of memory formation gets done by protein synthesis and connection formation between existing neurons. Yet this press release implies a role for neurogenesis in longer term memory formation.

Here is the meat of the matter: A cut in neurogenesis allowed mice to use their working memory more efficiently.

Results of the study, conducted with mice, found that the absence of neurogenesis in the hippocampus improves working memory, a specific form of short-term memory that relates to the ability to store task-specific information for a limited timeframe, e.g., where your car is parked in a huge mall lot or remembering a phone number for few seconds before writing it down. Because working memory is highly sensitive to interference from information previously stored in memory, forgetting such information may therefore be necessary for performing everyday working memory tasks, such as balancing your check book or decision making.

“We were surprised to find that halting neurogenesis caused an improvement of working memory, which suggests that too much memory is not always a good thing, and that forgetting is important for normal cognition and behavior,” said Gaël Malleret, Ph.D., a research scientist at the Center for Neurobiology and Behavior at Columbia University Medical Center and the paper’s co-first author. “Altogether, our findings suggest that new neurons in the hippocampus have different, and in some cases, opposite roles in distinct types of memory storage, and that excess neurogenesis can be detrimental to some memory processes.”

Maybe there's a trade-off between better use of memory on a given day versus formation of long term memories. Enhancement of neurogenesis might turn out to boost, for example, the memory formation of a medical student who is trying to memorize all the bones and muscles in the body. Does halting of neurogenesis reduce the formation of long term memories in mice?

Attempts to achieve Artificial Intelligence (AI) will need to avoid excessive memory formation. Also, attempts to boost new memory formation in humans and other animals will need to weigh the costs to working memory function.

“We believe these findings have important implications for diverse disciplines ranging from medicine to artificial intelligence,” said Dr. Malleret. “In medicine, these findings have significant implications for possible therapeutic interventions to improve memory – a careful balance of neurogenesis would need to be struck to improve memory without overwhelming it with too much activity.”

I've love to double or triple my working memory set. This'll probably come much sooner for new babies by use of embryo genetic engineering. We'll probably gain the capability to boost offspring intelligence many years before we gain that same capability to change fully formed and extremely complex adult brains.

Then there are the memories that you don't much want to keep around. Some work is tedious and boring. Do you want to remember every time you did a highly repetitive task on an assembly line or other work setting? I guess you'd want to remember it only well enough to remind you to take steps necessary to avoid the need to work in such a job again.

By Randall Parker    2007 April 01 08:38 AM   Entry Permalink | Comments (2)
2007 February 11 Sunday
Lack Of Sleep Suppresses Neurogenesis And Memory Formation

Elizabeth Gould at Princeton University found that sleep deprivation in rats inhibits the replication of neural stem cells and therefore prevents creation of new neurons.

Prolonged sleep deprivation is stressful and has been associated with adverse consequences for health and cognitive performance. Here, we show that sleep deprivation inhibits adult neurogenesis at a time when circulating levels of corticosterone are elevated. Moreover, clamping levels of this hormone prevents the sleep deprivation-induced reduction of cell proliferation. The recovery of normal levels of adult neurogenesis after chronic sleep deprivation occurs over a 2-wk period and involves a temporary increase in new neuron formation. This compensatory increase is dissociated from glucocorticoid levels as well as from the restoration of normal sleep patterns. Collectively, these findings suggest that, although sleep deprivation inhibits adult neurogenesis by acting as a stressor, its compensatory aftereffects involve glucocorticoid-independent factors.

Professor Gould thinks that the lack of sleep produces the stress hormone glucocorticoid which suppresses neurogenesis.

In a recent study by psychology professor Elizabeth Gould, rats who were sleep-deprived for 72 hours exhibited increased levels of the stress hormone glucocorticoid. These high stress levels in turn reduced neurogenesis — the birth of new neurons — in the rats' hippocampuses, a part of the brain critical for learning and memory.

Harvard Medical School researcher Seung-Schik Yoo asked a human group to stay up all night and then showed them images. People who stayed up all night did not remember the images as well as those who were well rested when they saw the images.

They correctly identified 74% of the previously viewed images, on average. By comparison, another group who had a proper night’s rest before viewing the 150 images at the start of the experiment correctly identified 86% of these pictures in the pop quiz.

Adequate sleep is needed for proper brain functioning. Of course you already knew that. But maybe the scientific evidence will serve as a useful reminder that you ought to act on that knowledge.

By Randall Parker    2007 February 11 11:02 PM   Entry Permalink | Comments (4)
2006 October 15 Sunday
Acetylcholine Boosts Memory Formation In Rats

By stimulating acetylcholine neurotransmitter release scientists were able to enhance how well rats remembered lessons from a training session.

The levels of a chemical released by the brain determine how detailed a memory will later be, according to researchers at UC Irvine.

The neurotransmitter acetylcholine, a brain chemical already established as being crucial for learning and memory, appears to be the key to adding details to a memory. In a study with rats, Norman Weinberger, research professor of neurobiology and behavior, and colleagues determined that a higher level of acetylcholine during a learning task correlated with more details of the experience being remembered. The results are the first to tie levels of acetylcholine to memory specificity and could have implications in the study and treatment of memory-related disorders.

The findings appear in the November issue of the journal Neurobiology of Learning and Memory.

“This is the first time that direct stimulation of a brain region has controlled the amount of detail in a memory,” said Weinberger, a fellow at UCI’s Center for the Neurobiology of Learning and Memory. “While it is likely that the brain uses a number of mechanisms to store specific details, our work shows that the level of acetylcholine appears to be a key part of that process.”

In their experiments, the researchers exposed rats to tones of various frequencies. During some of the trials, they paired one tone with stimulation of a section of the rats’ brains known as the nucleus basalis, which relays commands to the auditory cortex by secreting acetylcholine. During some experiments, the stimulation of the nucleus basalis was weak, whereas in other animals the stimulation was stronger. When the tones were replayed the next day, the scientists could measure how well they remembered the various frequencies by measuring changes in their respiration rates.

The results showed that a weak activation of the nucleus basalis, which resulted in a small amount of acetylcholine being released, did lead the rats to remember the tones but not specific frequencies. However, when the stimulation was greater (leading to the higher level of acetylcholine release), the rats also remembered the specific frequencies.

You can take choline tablets to boost your brain acetylcholine. But acetylcholine released from nerve cells enhanced memory formation. Will choline boost acetylcholine release? My own experience with choline supplements is that they make me feel depressed. Your mileage may vary.

By Randall Parker    2006 October 15 09:24 PM   Entry Permalink | Comments (3)
2006 September 05 Tuesday
Anticipation Of Fear Increases Memory Formation

Get yourself on edge if you want to form lots of memories.

The UW-Madison scientists found that two key regions of the brain - the amygdala and the hippocampus - become activated when a person is anticipating a difficult situation. Scientists think the amygdala is associated with the formation of emotional memories, while the hippocampus helps the brain form long-term recollections, Nitschke says.

The researchers studied the brain activity of 36 healthy volunteers using a technique known as functional magnetic resonance imaging, which produces high-contrast images of human tissue. They began by showing the volunteers two kinds of signals. One was neutral, but the other indicated that some type of gruesome picture was soon to follow, such as explicit photos of bloody, mutilated bodies. Thirty minutes after the researchers had shown dozens of violent images, they quizzed study participants on how well they remembered the pictures they had just seen.

"We found that the more activated the amygdala and hippocampus had been during the anticipation [of the pictures], the more likely it was that a person would remember more of them right away," says Nitschke.

Two weeks after the experiment, scientists met with the study subjects again to measure how well they remembered the same disturbing images. This time, they found that people who best remembered them had shown the greatest amygdala and hippocampus activity during the picture-viewing exercise two weeks before. That suggested that those subjects' brains had already started converting short-term memories of the images into longer-lasting ones.

Mackiewicz says the anticipation of an uncomfortable situation probably kick-starts a kind of "arousal or fear circuitry" in the brain, which in turn helps to reinforce old memories.

"In the future, we could look for ways to dampen that arousal response in patients so that they do not evoke negative memories so easily," she adds.

We need drugs that'll turn on the amygdala and hippocampus so that we can form better memories.

By Randall Parker    2006 September 05 11:12 PM   Entry Permalink | Comments (4)
2006 March 25 Saturday
Frequent Tests Increase Memory Retention When Studying

The potential time savings from this report is enormous. The economic value ditto. Repeated testing improves longer term memory retention.

"Our study indicates that testing can be used as a powerful means for improving learning, not just assessing it," says Henry L. "Roddy" Roediger III, Ph.D., an internationally recognized scholar of human memory function and the James S. McDonnell Distinguished University Professor at Washington University.


In two experiments, one group of students studied a prose passage for about five minutes and then took either one or three immediate free-recall tests, receiving no feedback on the accuracy of answers. Another group received no tests in this phase, but was allowed another five minutes to restudy the passage each time their counterparts were involved in a testing session.

After phase one, each student was asked to take a final retention test presented at one of three intervals — five minutes, two days or one week later. When the final test was presented five minutes after the last study or testing session, the study-study-study-study (SSSS) group initially scored better, recalling 81 percent of the passage as opposed to 75 percent for the repeated-test group.

However, tested just two days later, the study-only group had forgotten much of what they had learned, already scoring slightly lower than the repeated-test group. Tested one week later, the study-test-test-test group scored dramatically better, remembering 61 percent of the passage as compared with only 40 percent by the study-only group.

The study-only group had read the passage about 14 times, but still recalled less than the repeated testing group, which had read the passage only 3.4 times in its one-and-only study session.

"Taking a memory test not only assesses what one knows, but also enhances later retention, a phenomenon known as the 'testing effect,'" says Roediger.

"Our findings demonstrate that the testing effect is not simply a result of students gaining re-exposure to the material during testing because students in our repeated-study group had multiple opportunities to re-experience 100 percent of the material but still produced poor long-term retention. Clearly, testing enhances long-term retention through some mechanism that is both different from and more effective than restudy alone."

This strikes me as an important result with obvious and very valuable practical applications. Problem: Labor costs for testers are too high. But that can be solved by use of computer programs. Picture online books with associated online tests. You could read each section of a book and then click your way into a test about it and do the test.

I'd like to see technical computer books come with associated tests. Someone tell Tim O'Reilly, New Rider Publishing, and similar tech book publishers.

There's an obvious implication to this result: Most tests should be done to improve memory retention, not for grades. Tests delivered around the time of learning some material should be seen as drills to exercise the memory rather than for scoring to assign grades. Tests for grades could come much later after memory formation has become well advanced.

I've always thought that tests for a subject given right after learning the material (e.g. the material taught during the last couple of weeks of a college course) aren't testing for permanent memory formation. Well, look at the results above. Two groups can score close to the same level of knowledge at one point but due to differences in how they learned the material they can have very different longer term patterns of memory retention.

I've long advocated for tests one can take to earn college credits for most college courses (particularly the subjects with clearer objective bodies of knowledge such as the hard sciences, math, and engineering subjects) without having to enroll in and attend an entire course. Such tests should require that a person pass the same tests in two more more separate sessions several weeks apart. Someone who can pass a test and then pass it again 4 and 8 weeks later will retain the information far better than the average person who crams to take college course finals.

Also see my ParaPundit posts Accelerate Education To Increase Tax Revenue, Reduce Costs and Walter Russell Mead For Standard National Tests.

By Randall Parker    2006 March 25 02:02 PM   Entry Permalink | Comments (7)
2006 March 15 Wednesday
Researchers Find Woman With Extremely Good Memory

A woman with the best known memory of her past has been identified by UC Irvine researchers.

Researchers at UC Irvine have identified the first known case of a new memory syndrome - a woman with the ability to perfectly and instantly recall details of her past. Her case is the first of its kind to be recorded and chronicled in scientific literature and could open new avenues of research in the study of learning and memory.

Researchers Elizabeth Parker, Larry Cahill and James L. McGaugh spent more than five years studying the case of "AJ," a 40-year-old woman with incredibly strong memories of her personal past. Given a date, AJ can recall with astonishing accuracy what she was doing on that date and what day of the week it fell on. Because her case is the first one of its kind, the researchers have proposed a name for her syndrome - hyperthymestic syndrome, based on the Greek word thymesis for "remembering" and hyper, meaning "more than normal."

Their findings are published in the current issue of the journal Neurocase.

I'd like to have controllable hyperthymestic syndrome syndrome. No need to remember very boring and tedious tasks. But when listening to a lecture or reading an important article it would be handy to be able to think a thought to activate a greatly enhanced ability to form memories.

"What makes this young woman so remarkable is that she uses no mnemonic devices to help her remember things," said McGaugh, a National Academy of Sciences member and a pioneer in the field of memory research. "Her recall is instant and deeply personal, related to her own life or to other events that were of interest to her."

AJ's powers of recollection can be astonishing. In 2003, she was asked to write down all the Easter dates from 1980 onward. In 10 minutes, and with no advance warning, she wrote all 24 dates and included what she was doing on each of those days. All the dates except for one were accurate. The incorrect one was only two days off. Two years later when she was asked, again without warning, the same question, she quickly responded with all the correct dates and similar information about personal events on those dates.

There are limits to AJ's memory. While she has nearly perfect recall of what she was doing on any given date and instantly can identify the date and day of the week when an important historical event in her lifetime occurred, she has difficulty with rote memorization and did not always do well in school. She scored perfectly on a formal neuropsychological test to measure her autobiographical memory, but during the testing had difficulty organizing and categorizing information. She refers to her ongoing remembering of her life's experiences as "a movie in her mind that never stops".

The Easter dates trick strikes me more as a form of a specialized savant talent. While on a high school tour of a mental institute I once met a guy making pottery who could tell you the day of the week for any day in the past. He did it instantly with no seeming delay after being asked.

By Randall Parker    2006 March 15 09:51 PM   Entry Permalink | Comments (5)
2005 February 03 Thursday
False Memory Formation Looks Different Under Brain Scan

Johns Hopkins University scientist Craig Stark and graduate student Yoko Okado have shown using functional magnetic resonance imaging (fMRI) of the brain that the prefrontal lobe is less active when minds are forming inaccurate memories.

Using advanced, non-invasive imaging techniques, Yoko Akado and Craig Stark compared the areas of the brain that were active when a subject was encoding a complex event and afterwards, during exposure to misleading information. For example, subjects were asked to watch a vignette comprised of 50 photographic slides showing a man stealing a woman's wallet, then hiding behind a door. A little later, the subjects were shown what they thought was the same sequence of slides but unbeknownst to them the second set of slides contained a misleading item and differed in small ways from the original--the man hid behind a tree, for example, not a door.

Two days later, the subjects took a memory test, which asked them to recall details such as where the man hid, and which presentation--the first, second, or both--contained that information. Memory for a misinformation item was scored as a false memory only if the subject attributed the item to either the original presentation or to both the original and second slide presentations.

Stark and Akado found clear evidence that the subjects' brain activity predicted if their memories of the theft would be accurate or false. Consistent with findings from numerous previous studies that have reported that areas such as the hippocampus are highly active during memory formation, Okado and Stark found activity in the left hippocampus tail as well as perirhinal cortex was correlated with successful encoding of an item in memory, even when the memory that was formed was for a false item. But in subjects who had formed false memories, it was noticeable that activity in other brain areas such as the prefrontal cortex was weak during exposure to the second sequence of slides compared to during the original viewing.

Okada and Stark suggest that activity in the prefrontal cortex is correlated to encoding the source, or context, of the memory. Thus, weak prefrontal cortex activity during the misinformation phase indicates that the details of the second experience were poorly placed in a learning context, and as a result more easily embedded in the context of the first event, creating false memories.

Are people who take a more critical view of what they see less prone to false memory formation? Is there a type of brain that can be recognized on scans that is less prone to being fooled by misleading images?

The real problem is in how to detect whether a memory is true or false after the fact. Might brain scans studies eventually show that during memory recall false memories show a different pattern of brain activity on average as compared to accurate memories?

The research paper, published in the jourrnal Learning & Memory is available online here and here as PDF and here in HTML. Also, here is an excerpt from the abstract.

Two interaction patterns between encoding phase (Original Event and Misinformation) and type of memory (true and false) were observed in MTL and PFC regions. In the left hippocampus tail and perirhinal cortex, a predictive item-encoding pattern was observed. During the Original Event phase, activity was greater for true than false memories, whereas during the Misinformation phase, activity was greater for false than true memories. In other regions, a pattern suggestive of source encoding was observed, in which activity for false memories was greater during the Original Event phase than the Misinformation phase. Together, these results suggest that encoding processes play a critical role in determining true and false memory outcome in misinformation paradigms.

By Randall Parker    2005 February 03 03:35 AM   Entry Permalink | Comments (1)
2004 November 15 Monday
Minds Better Remember Initial Responses To Situations

Be careful what you choose to learn first.

Nov. 11, 2004 — No matter how hard we try to change our behaviors, it's the old ways that tend to win out over time, especially in situations where we're rushed, stressed or overworked, suggests a new study of human memory from Washington University in St. Louis.

"Our study confirms that the responses we learn first are those that remain strongest over time," says Larry Jacoby, Ph.D., a professor of psychology in Arts & Sciences at Washington University and co-author of the study.

The study, titled "Which Route to Recovery? Controlled Retrieval and Accessibility Bias in Retroactive Interference," appears in the November issue of Psychological Science, a journal of the American Psychological Society. The research was conducted at Washington University by Jacoby and two other psychologists: Cindy Lustig, now at the University of Michigan, and Alex Konkel, now at the University of Illinois.


Participants in the study first learned one way of responding to a cue word (e.g., "Say 'cup' when you see 'coffee' "), and then later learned another way (e.g., "Now say 'mug' when you see 'coffee' "). They were given memory tests both immediately after learning the words, and the day after. Some people were told to control their memory and give only the first response ('cup'). Others were told to just give whichever response came automatically to mind.

Those controlling their responses did a good job of giving only the first response on both days. The interesting results were for the people who responded automatically, giving whichever response came to mind. On the first day, their answers were split evenly between the two possibilities. However, on the second day, they gave the first response ('cup') much more often than the second response ('mug'). The second response seemed to fade from memory, while the first response grew even stronger than it had been on the first day.

In their study, the researchers sought to take a new look at why old habits seem to prevail over our attempts to change our behavior. Their findings suggest that even though the strength of an old habit may fade over time, our memory for it will be stronger then any new good intentions that succeed it.

This helps to explan why people too often revert to practicing old bad habits when they are trying to follow newer and better habits. One practical suggestion comes from this report: If you are going to learn two behaviors that you will use to respond to some situation and you think you'll be better off doing one of the two behaviors more often then learn that behavior first.

By Randall Parker    2004 November 15 03:11 AM   Entry Permalink | Comments (0)
2004 September 15 Wednesday
Stroke Victim Reveals Brain Location For Deaming

An elderly woman who suffered a stroke that caused her to lose the ability to dream was found to have brain damage to a specific location in the back of the brain.

In a study published September 10, 2004, in the online edition of the Annals of Neurology, scientists describe a patient who lost all dreaming, and very little else, following a stroke in one distinct region of the brain, suggesting that this area is crucial for the generation of dreams.

"How dreams are generated, and what purpose they might serve, are completely open questions at this point. These results describe for the first time in detail the extent of lesion necessary to produce loss of dreaming in the absence of other neurological deficits. As such, they offer a target for further study of the localization of dreaming," said author Claudio L. Bassetti, M.D., of the Department of Neurology at the University Hospital of Zurich in Switzerland.

These unique scientific observations began with an unfortunate event: a stroke suffered by a 73-year-old woman. When blood flow was disrupted to a relatively small area deep in the back part of her brain, she lost a number of brain functions.

Most of these disabilities were related to vision, which was not unexpected, since one of the brain functions localized to this area of the brain is the processing of visual information.

Fortunately, within a few days of the stroke, the visual problems had gone away. But a new symptom emerged: The patient stopped dreaming.

Such loss of dreaming--along with visual disturbances--following damage to a specific part of the brain goes by the name Charcot-Wilbrand syndrome, named for the eminent neurologists Jean-Martin Charcot and Hermann Wilbrand, who first described it in the 1880s.

The syndrome is quite rare, especially cases that lack symptoms other than dream loss. Bassetti, then at the University of Bern, and his colleague Matthias Bischof, M.D, realized that this woman's misfortune might provide valuable answers to the localization of dreaming in the brain.

For six weeks following the stroke, the researchers studied the patient's brain waves as she slept. They found no disruptions in her sleep cycle. The fact that REM sleep continued normally was significant, because dreaming and REM sleep occur together, though research has pointed to different brain systems underlying the two. These results appear to confirm that dreaming and REM sleep are driven by independent brain systems.

Before the stroke, the patient recalled, she had experienced dreams three to four times a week. She now reported no dreams, even when awakened during REM sleep.

With time, some dreaming function did return. A year after the stroke, she experienced occasional dreams, but no more than one per week. The dreams were of a reduced vividness and intensity compared to before the stroke.

With MRI scans, Bischof and Bassetti determined that the stroke had damaged areas located deep in the back half of the brain. Recent research has shown that some of this region is involved in the visual processing of faces and landmarks, as well as the processing of emotions and visual memories, a logical set of functions for a brain area that would generate or control dreams.

Dreaming may not be necessary and may be a side effects of processes conducted to achieve other outcomes.

But more interesting than the location is the fact that everything else about the woman seemed to be normal. She showed no signs of any problems with memory, attention or any other mental abilities, and beyond a few visual disturbances in the first few days, normal vision. “She has no other cognitive problems after a full clinical assessment,” says Bassetti. “She has a normal visual imagination.”

But did this woman really not lose any cognitive function other than the ability to dream? Can she form long term visual memories as well now as she could before the stroke? Since her cognitive abilities were not measured in detail before the stroke we can't be certain that she didn't lose any cognitive abilities.

People who stop having REM (Rapid Eye Movement) sleep while on anti-depressant drugs also do not appear to suffer cognitive deficiencies as a result.

At present, the functions of REM sleep are as elusive as those of dreaming. Adults spend a quarter of their nightly slumber in REM sleep, scattered throughout the night. The remaining time is spent deeper in unconsciousness. So REM may simply bring the brain back from deep sleep periodically to help us wake up if we need to, says Horne.

So then do people who don't experience REM sleep wake up more slowly than those who have REM episodes in sleep?

By Randall Parker    2004 September 15 02:48 PM   Entry Permalink | Comments (1)
2004 June 08 Tuesday
Brain Slow Wave Activity In Sleep Higher When Learning

If one learns a task in the evening then the amount of slow-wave activity (SWA) in the brain while sleeping is increased.

Giulio Tononi of the University of Wisconsin-Madison and his colleagues measured electrical brain signals in subjects who learned a simple computer game before going to sleep.

The kind of activity that occurs during sleep was increased in a penny-sized region in the brains of slumbering subjects who had learned the game. Just playing the game did not have this effect. The researchers conclude that sleep falls on brain circuits that have been changed, not just used, during the day.

And someone with more of such activity in this area, which is in the top right hemisphere, tends to perform better in the morning, they report in a paper published online by Nature1

This study brings up an interesting question: Is one better off learning things right before bedtime rather than earlier in the day? Is new learning more likely to be translated into lasting changes in brain wiring if the learning episode is closer to the time one goes to sleep? The idea seems plausible because mice delayed from getting to sleep after learning have their learning blocked. So evening is probably the better time to study.

Think of each sleep episode as a chance to learn more information. Looked at in that light it may make more sense to spread learning out over longer periods by studying every day rather than concentrating a larger amount of learning into a smaller number of days. Also, it might make more sense to learn a lot on days when you know you'll be able to get a full night's sleep.

I've previously argued that the development of drugs that would allow more rapid cycling through sleep and wakefulness might allow accelerated learning. Also see my previous post Long Term Memories Processed By Anterior Cingulate.

By Randall Parker    2004 June 08 02:21 PM   Entry Permalink | Comments (5)
2004 May 07 Friday
Long Term Memories Processed By Anterior Cingulate

Alcino J. Silva at UCLA, Paul Frankland (now at University of Toronto) and coworkers at UCLA have discovered that the anterior cingulate of the cortex of the brain plays a key role in the formation and recall of long term memories.

First, the scientists engineered mice with a mutant form of a gene called kinase II, which eliminates the ability to recall old memories. The animals were trained to recognize a cage, then tested for their memory of the cage at one, three, 18 and 36 days after training.

"We found that the mutant mice recognized the cage for up to three days after training, but their memory of the cage disappeared after 18 and 36 days," Silva said. "While they possessed short-term recall, they never developed a distant memory of the cage."

Earlier research suggested that the cortex — or outer layer of the brain — plays a role in the storage and retrieval of old memories.

Once memories became weeks old their recall caused the anterior cingulate to light up in brain scans.

In their second strategy, the UCLA researchers used imaging methods to track visually which regions of a normal mouse's cortex grew active during memory testing.

No part of the cortex lit up when the animal was exposed to the cage one day after training. When the mouse saw the cage 36 days after training, however, the images highlighted a part of the cortex called the anterior cingulate.

"We were fascinated to see the anterior cingulate switch on when we tested the normal mice for distant memory, but not when we tested them for recent memory," Silva said. "In contrast, the mutant mice's anterior cingulate never switched on during tests for distant memory.

"This result suggests that the kinase II mutation disrupted processes in the anterior cingulate that are required for recalling distant memories," he said.

Disabling the anterior cingulate appears to selectively prevent access to older memories.

Third, the UCLA team injected normal mice with a drug that temporarily turned off the anterior cingulate. The scientists discovered that disabling the anterior cingulate did not disrupt the animals' memory of the cage at one and three days after training, but did interrupt the mice's memory of the cage at 18 and 36 days after training.

"When we silenced the anterior cingulate, the mice kept their recent memory of the cage, but lost their distant memory," Silva said. "This was consistent with our two earlier findings.

"We now had several pieces of evidence all pointing to the same conclusion," he said. "The anterior cingulate plays a special role in keeping our early memories alive. Our work with the mutant mice also suggests that kinase II is critically involved in preserving our oldest memories."

When a person recalls a memory, Silva theorizes, the anterior cingulate rapidly assembles the signals of the memory from different sites in the brain.

"If the anterior cingulate malfunctions, a recalled memory may be too fragmented to make sense to the person," Silva said. "It's like a puzzle with missing pieces. This could be what occurs during dementia."

The formation of long term memories takes weeks.

The formation of new memories is thought to involve the strengthening of synaptic connections between groups of neurons. Remembering involves the reactivation of the same group, or network, of neurons. As memories age, the networks gradually change. Initially, memories for everyday life events appear to depend on networks in the region of the brain called the hippocampus. However, over time, these memories become increasingly dependent upon networks in the region of the brain called the cortex.

"We believe there is active interaction between the hippocampus and cortex, and that the transfer process of memories between these two regions in the brain occurs over several weeks, and likely during sleep," added Dr. Frankland, holder of the Canada Research Chair in Cognitive Neurobiology.

Curiously, this points to a deficiency in how schools and colleges test for knowledge. If students learn something a week before finals then what they are being tested on is their short term memory version of their knowledge of the material. If the goal is to test for long term memory it really becomes necessary to test for the knowledge more than once with weeks between the tests.

Also, drugs and other methods of enhancing long term memory formation must enhance processes in the brain that occur over a period of weeks.

This builds on some work done at MIT which found that a kinase mutation in mice blocked the ability to form long term memories.

By Randall Parker    2004 May 07 02:41 AM   Entry Permalink | Comments (3)
2004 March 02 Tuesday
Hippocampus Sorts Information Into Memory Categories

Monkey brains remember things in part by placing them into pre-existing categories.

“When you need to remember people you’ve just met at a meeting, the brain probably doesn’t memorize each person’s facial features to help you identify them later,” says Sam Deadwyler, Ph.D., a Wake Forest neuroscientist and study investigator. “Instead, it records vital information, such as their hairstyle, height, or age, all classifications that we are familiar with from meeting people in general. Our research suggests how the brain might do this, which could lead to ways to improve memory in humans.”

The researchers found that when monkeys were taught to remember computer clip art pictures, their brains reduced the level of detail by sorting the pictures into categories for recall, such as images that contained “people,” “buildings,” “flowers,” and “animals.”

The categorizing cells were found in the hippocampus, an area of the brain that processes sensory information into memory. It is essential for remembering all things including facts, places, or people, and is severely affected in Alzheimer’s disease.

“One of the intriguing questions is how information is processed by the hippocampus to retain and retrieve memories,” said Robert Hampson, Ph.D., co-investigator. “The identification of these cells in monkeys provides evidence that information can be remembered more effectively by separating it into categories. It is likely that humans use a similar process.”

The researchers measured individual cell activity in the hippocampus while the monkeys performed a video-game-like memory task. Each monkey was shown one clip art picture, and after a delay of one to 30 seconds, picked the original out of two to six different images to get a juice reward.

By recording cell activity during hundreds of these trials in which the pictures were all different, the researchers noticed that certain cells were more active when the pictures contained similar features, such as images of people – but not other objects. They found that different cells coded images that fit different categories.

One really interesting aspect of this report is that different monkeys developed different ways for categorizing the same sensory inputs:

“Unlike other cells in the brain that are devoted to recording simply an object’s shape, color or brightness, the category cells grouped images based on common features – a strategy to improve memory,” said Terry Stanford, Ph.D., study investigator. “For example, the same cell responded to both tulips and daisies because they are both flowers.”

The researchers found, however, that different monkeys classified the same pictures differently. For example, with a picture of a man in a blue coat, some monkeys placed the image in the “people” category, while others appeared to encode the image based on features that were not related to people such as “blue objects” or “types of coats."

While such categorization is a highly efficient memory process, it may also have a downside, said the researchers.

“The over generalization of a category could result in errors,” said Deadwyler. “For example, when the trials included more than one picture with people in it, instead of different images, the monkeys often confused the image with a picture of other people.”

This really matches with what one would expect intuitively. A doctor is going to look at people and remember them by disease characteristics. A fashion magazine editor is going to remember them by types of clothing and jewelry worn. Others with different previous training and life experiences are going to split people and things up in different ways. There obviously must be ways that networks of neurons have formed to favor different approaches for filtering and categorizing sensory input.

The process of choosing categories in your mind to sort what you learn and experience is an important part of becoming an effective learner and analyzer of information.

By Randall Parker    2004 March 02 01:28 AM   Entry Permalink | Comments (18)
Different Parts Of Brain Remember Boring, Exciting Words

How well the mind remembers and what part of the brain is involved in memory formation depends on whether the words being memorized are emotionally arousing.

For the study, Elizabeth Kensinger, a researcher in MIT's Department of Brain and Cognitive Sciences, and Suzanne Corkin, professor of behavioral neuroscience in the same department, asked 14 men and 14 women to "learn" 150 words related to events, while the participants brains were being scanned in an fMRI (functional magnetic resonance imaging) procedure. Some of the words represented arousing events, such as "rape" or "slaughter." Others were nonarousing, such as "sorrow" and "mourning."

They then tested the participants to see which of the words they remembered having been shown. Kensinger and Corkin found that Mb

"This result suggests that stress hormones, which are released as part of the response to emotionally arousing events, are responsible for enhancing memories of those events," said the researchers. "We think that detailed cognitive processing may underlie the enhanced memory for the nonarousing events."

Memory storage can be enhanced by associating memories with emotionally exciting events. But use of such a technique raises a question that one ought to ponder before trying to learn important material while, say, scaring oneself watching a scary movie: Do you want various memories to be stored in areas of the brain associated with strong emotional reactions? Doing so may make the memories easier to recall but will also probably cause emotional reactions upon recall. Sometimes it makes sense to place memories where they will be linked to various emotional reactions. But in other cases it makes more sense to be able to retrieve some memories without having to feel a potentially stressful and draining emotional reaction.

It would be useful to be able to measure the intensity and type of emotional reactions as memories are recalled. Then it would be even more useful to be able to it would be useful to be able to disconnect the recall of a particular set of memories with the evocation of an undesired emotional reaction.

This result is not surprising either intuitively or based on previous scientific results. Also see my previous post Gory Pictures Improve Memory Retention.

By Randall Parker    2004 March 02 12:47 AM   Entry Permalink | Comments (3)
2004 February 12 Thursday
Brain Has Separate Areas For Actual And Interpreted Sensory Data

But we decide what is right and which is an illusion.

But a new collaborative study involving a biomedical engineer at Washington University in St. Louis and neurobiologists at the University of Pittsburgh shows that sometimes you can't believe anything that you see. More importantly, the researchers have identified areas of the brain where what we're actually doing (reality) and what we think we're doing (illusion, or perception) are processed.

Daniel Moran, Ph.D., Washington University assistant professor of biomedical engineering and neurobiology, and University of Pittsburgh colleagues Andrew B. Schwartz, Ph.D., and G. Anthony Reina, M.D., focused on studying perception and playing visual tricks on macaque monkeys and some human subjects. They created a virtual reality video game to trick the monkeys into thinking that they were tracing ellipses with their hands, though they actually were moving their hands in a circle.

They monitored nerve cells in the monkeys enabling them to see what areas of the brain represented the circle and which areas represented the ellipse. They found that the primary motor cortex represented the actual movement while the signals from cells in a neighboring area, called the ventral premotor cortex, were generating elliptical shapes.

The mind has the capability to create an interpreting facility to map between what it sees and how it perceives what it sees. This allows the mind to adjust for the effects of bifocals and other sense-distorting factors. While this capability is adaptive it can sometimes be tricked into creating erroneous interpretations of sensory input.

The research shows how the mind creates its sense of order in the world and then adjusts on the fly to eliminate distortions.

For instance, the first time you don a new pair of bifocals, there is a difference in what you perceive visually and what your hand does when you go to reach for something. With time, though, the brain adjusts so that vision and action become one. The ventral premotor complex plays a major role in that process.

Knowing how the brain works to distinguish between action and perception will enhance efforts to build biomedical devices that can control artificial limbs, some day enabling the disabled to move a prosthetic arm or leg by thinking about it.

Results were published in the Jan. 16, 2004 issue of Science.

"Previous studies have explored when things are perceived during an illusion, but this is the first study to show what is being perceived instead of when it is happening," said Moran. "People didn't know how it was encoded. And we also find that the brain areas involved are right next to each other."

Think back to childhood. We all had to learn to judge the distance of our hands from our faces by how the hands became smaller and the angles of the arms showed the hands changing position. We now all make those interpretations and many similar interpretations of raw sense material quite subconsciously. But we need the ability to change those interpretations as we grow older and our senses decline or because we encounter new environments which create new patterns of sensory input.

By Randall Parker    2004 February 12 03:44 PM   Entry Permalink | Comments (1)
2004 February 09 Monday
MIT Researchers Find Molecular Pathway For Memory Formation

A kinase enzyme (which transfers a phosphate onto a protein - which often turns a protein into a less or more active state) called Mitogen-Activated Protein Kinase (MAPK) has been found to play a crucial role in increasing the synthesis of a large assortment of different proteins needed for long-term memory formation.

The MIT research team, led by Nobel laureate Susumu Tonegawa, director of the Picower Center for Learning and Memory, has now identified a crucial molecular pathway that allows neurons to boost their production of new proteins rapidly during long-term memory formation and synaptic strengthening.

"What we have discovered that hasn't been established before is that there is a direct activational signal from the synapse to the protein synthesis machinery," said Tonegawa, the Picower Professor of Biology and Neuroscience in MIT's Departments of Brain and Cognitive Sciences and Biology The central component of this pathway, an enzyme called "mitogen-activated protein kinase" (MAPK), effectively provides a molecular switch that triggers long-term memory storage by mobilizing the protein synthesis machinery.

Acting on a hunch that MAPK might be an important part of such a "memory switch," Ray Kelleher, a postdoctoral fellow in Tonegawa's laboratory and lead author of the study, created mutant mice in which the function of MAPK was selectively inactivated in the adult brain. Intriguingly, he found that these mutant mice were deficient in long-term memory storage. In contrast to normal mice's ability to remember a behavioral task for weeks, the mutant mice could remember the task for only a few hours. Similarly, the researchers found that synaptic strengthening was also much more short-lived in neurons from the mutant mice than in neurons from normal mice.

Realizing that the pattern of impairments in mutant mice suggested a problem with the production of new proteins, the researchers then performed an elegant series of experiments that revealed precisely how MAPK translates synaptic stimulation into increased protein synthesis. Based on molecular comparisons of neurons from normal and mutant mice, they found that synaptic stimulation normally activates MAPK, and the activated form of MAPK in turn activates several key components of the protein synthesis machinery. This direct regulation of the protein synthesis machinery helps explain the observation that activation of MAPK enhanced the production of a broad range of neuronal proteins.

"Many people had thought that long-term memory formation involved only boosting the synthesis of a very limited set of proteins," said Tonegawa. "But to our surprise, this process involves 'up-regulating' the synthesis of a very large number of proteins."

This information may be useful for researchers trying to develop memory formation enhancement drugs. A drug that upregulates MAPK synthesis or that turns on its activity might have the effect of enhancing memory formation.

As the steps in memory formation becomes identified and better understood they all become potential targets for drug therapies. The same holds true for emotional reactions and other aspects of cognitive function. As any biological system becomes better understood it becomes more manipulable. Where is this all going to lead? It seems likely that most people 30 or 40 years from now will be using drugs to enhance and fine-tune the performance their brains in a variety of ways. While many people use drugs today for either recreation purposes or to treat mental disorders it seems likely that the focus of drug use for altering the mind will shift toward cognitive enhancement in the future both to improve thinking and to align one's emotional reactions more closely with goals one wants to achieve..

By Randall Parker    2004 February 09 11:58 PM   Entry Permalink | Comments (3)
2004 January 21 Wednesday
REM And Slow-Wave Sleep Needed For Memory Consolidation

Duke University researchers have found studying rats that memory formation occurs in the slow-wave and rapid eye movement (REM) sleeping states. (same article here and shorter press release here)

In their study, the researchers placed about 100 infinitesimal recording electrodes in the brains of rats, in four regions involved in memory formation and sensory processing. Those brain areas included the hippocampus, which is widely believed to be involved in memory storage, and areas of the forebrain involved in rodent-specific behaviors. The scientists employed the same neural recording technology that Nicolelis and his colleagues used to enable monkeys to control a robot arm, an achievement announced in October 2003.

The researchers next exposed the rats to four kinds of novel objects in the dark, since largely nocturnal rodents depend on the sense of touch via their whiskers to investigate their environment. The four objects were a golf ball mounted on a spring, a fingernail brush, a stick of wood with pins attached and a tube that dispensed cereal treats.

The researchers recorded and analyzed brain signals from the rats before, during and after their exploration, for several days across natural sleep-wake cycles. Analyses of those signals revealed "reverberations" of distinctive brain wave patterns across all the areas being monitored for up to 48 hours after the novel experience.

According to Ribeiro, "We found that the activity of the brain when the animal is in a familiar environment does not 'stick' -- that is, the brain keeps moving from one state to another. In contrast, when the animal is exploring a novel environment, that novelty imposes a certain pattern of activity, which lingers in all the areas we studied. Also, we found that this pattern was much more prevalent in slow-wave sleep than in REM sleep."

Conversely, previous studies by Ribeiro and his colleagues demonstrated that the activation of genes able to effect memory consolidation occurs during REM sleep, not slow-wave sleep.

"Based on all these results, we're proposing that the two stages play separate and complementary roles in memory consolidation," he said. "Periods of slow-wave sleep are very long and produce a recall and probably amplification of memory traces. Ensuing episodes of REM sleep, which are very short, trigger the expression of genes to store what was processed during slow-wave sleep." In principle, this model explains studies such as those by Robert Stickgold and his colleagues at Harvard University, showing that both slow-wave and REM sleep have beneficial effects on memory consolidation, he said. According to Nicolelis, the new experiments remedy shortcomings of previous studies.

Of course what we all want is to be able to more easily store selected memories. Suppose more sophisticated sleeping drugs are developed that can selectively cause humans to spend more time in slow-wave and REM sleep. Will that boost memory formation? Suppose it did. I think one would want to exercise restraint in the use of such drugs. Do you want to remember the most boring details of your most boring days? I think not. It might even make sense to crowd your most important learning-intense activities into particular days so that you can remember new knowledge from those days in special intense memory formation sleeping sessions.

The genes identified that are up-regulated by the REM stage of memory storage are a point of particular interest. Another approach that might boost memory formation would be induce the expression of genes involved in memory formation. The problem, though is that a drug that upregulated their expression might be too broad in its effects causing the genes to be expressed all the time rather than just in the phase of REM sleep when memories are normally consolidated.

Drugs capable of inducing specific sleeping states and drugs capable of turning on genes used in particular sleeping states hold out the potential of creating states of the mind that would be hybrid states that are between sleeping and waking states. Whether those hybrid mental states would end up being useful in practice remains to be seen. Perhaps it will eventually be possible to use sleep state regulating drugs in the following way: One could study a subject really intensely for an hour or two and then hook oneself up to an automatic drug dispensing device (which might even be an embedded device) that would release drugs that would throw one very quickly and successively into slow-wave and REM sleep states to consolidate the memories of what one was studying. Then the drugs would be stopped and another drug would bring you back awake with the last couple of hours of memories consolidated. Using this approach one might be able to then cycle through several cycles of learning and sleeping states in a single day. This would allow humans to escape from some of the limits caused by the evolutionary legacy of our ancestors being exposed the 24 hour cycle of light and dark caused by the period of rotation of the Earth back before Edison's invention of the electric light bulb.

The full text of the article is available free on-line in the journal Public Library of Science Biology (PLoS Biology) in three formats. First, a synopsis of the work:

Brain Activity during Slow-Wave Sleep Points to Mechanism for Memory
Full-text | Print PDF (2607K) | Screen PDF (326K)

The research paper for the work:

Long-Lasting Novelty-Induced Neuronal Reverberation during Slow-Wave Sleep in Multiple Forebrain Areas
Sidarta Ribeiro, Damien Gervasoni, Ernesto S. Soares, Yi Zhou, Shih-Chieh Lin, Janaina Pantoja, Michael Lavine, Miguel A. L. Nicolelis
Full-text | Figures | Print PDF (11762K) | Screen PDF (732K)

PloS Biology even has a list of news articles reporting on this paper here.

By Randall Parker    2004 January 21 07:11 PM   Entry Permalink | Comments (3)
2004 January 09 Friday
Stanford Researchers Find Evidence Of Memory Supression Mechanism

Using functional magnetic resonance imaging (fMRI) researchers at Stanford University have found additional evidence that the brain has biological mechanisms for making specific memories harder to access.

Anderson first revealed the existence of such a suppression mechanism in the brain in a 2001 paper published in Nature titled "Suppressing Unwanted Memories by Executive Control." He took the research a step further at Stanford by using brain imaging scans to identify the neural systems involved in actively suppressing memory. The core findings showed that controlling unwanted memories was associated with increased activation of the left and right frontal cortex (the part of the brain used to repress memory), which in turn led to reduced activation of the hippocampus (the part of the brain used to remember experiences). In addition, the researchers found that the more subjects activated their frontal cortex during the experiment, the better they were at suppressing unwanted memories.

"For the first time we see some mechanism that could play a role in active forgetting," Gabrieli said. "That's where the greatest interest is in terms of practical applications regarding emotionally disturbing and traumatic experiences, and the toxic effect of repressing memory." The Freudian idea is that even though someone is able to block an unpleasant memory, Gabrieli said, "it's lurking in them somewhere, and it has consequences even though they don't know why in terms of their attitudes and relationships."

The experiment

Twenty-four people, aged 19 to 31, volunteered for the experiment. Participants were given 36 pairs of unrelated nouns, such as "ordeal-roach," "steam-train" and "jaw-gum," and asked to remember them at 5-second intervals. The subjects were tested on memorizing the word pairs until they got about three-quarters of them right -- a process that took one or two tries, Anderson said.

The participants then were tested while having their brains scanned using functional magnetic resonance imaging (fMRI) at Stanford's Lucas Center for Magnetic Resonance Spectroscopy. The researchers randomly divided the 36 word pairs into three sets of 12. In the first set, volunteers were asked to look at the first word in the pair (presented by itself) and recall and think about the second word. In the second set, volunteers were asked to look at the first word of the pair and not recall or think of the second word. The third set of 12 word pairs served as a baseline and was not used during the brain scanning part of the experiment. The subjects were given four seconds to look at the first word of each pair 16 times during a 30-minute period.

After the scanning finished, the subjects were retested on all 36 word pairs. The researchers found that the participants remembered fewer of the word pairs they had actively tried to not think of than the baseline pairs, even though they had not been exposed to the baseline group for a half-hour.

"People's memory gets worse the more they try to avoid thinking about it," Anderson said. "If you consistently expose people to a reminder of a memory that they don't want to think about, and they try not to think about it, they actually don't remember it as well as memories where they were not presented with any reminders at all."

While the unlocking of repressed memories has been viewed by Freudians as a worthwhile goal of therapy it is not obvious that this should be the case. If someone can clearly recall a painful memory then the recall is bound to cause many of the same painful emotional reactions that the original incident caused. Well, why put oneself through the same experience again? Isn't there a lot of advantage to making painful memories hard to access in order to reduce the likelihood of being reminded of them?

Debriefing after a traumatic event has been called into question as a useful method for counseling the victims of traumatic experiences. It may well be that debriefing doesn't work because it causes the mind to go over the traumatic events and therefore it may strengthen memory formation and later painful recall.

Perhaps what is needed is the ability to place removable blocks on memories. I'm thinking of something along the line of the ability to recall past memories when it becomes critical to do so. If any of you have read Roger Zelazny's Today We Choose Faces then imagine the ability to recall past memories of past clones without having to die in order to do so. One could even place tags on memories explaining why one might want to peer into them. For instance, a person thinking of remarrying might want to gain better access to memories of what went wrong in a previous marriage. Or on an anniversary date of the death of a loved one one might want to make the memories of time spent with that person more accessible.

The Stanford researchers were working with very new memories. But in rats the protein synthesis inhibitor anisomycin has been successfully used to erase 45 day old memories See the previous post Consolidated Memories Are Erasable In Rats.

By Randall Parker    2004 January 09 04:58 PM   Entry Permalink | Comments (1)
2003 November 10 Monday
False Versus Real Memory Recall Looks Different In MRI Brain Scan

Functional Magnetic Resonance Imaging (fMRI) can detect differences in brain patterns when brains correctly and incorrectly think they have seen an image before.

Neuroimaging techniques can help determine if the neural processes driving this retrieval of inaccurate memories are different from those that drive the retrieval of accurate memories. Several research groups are using functional magnetic resonance imaging (fMRI) to address this question. The hope is that neuroimaging can help determine the various potential sources of false memories.

Daniel Schacter, PhD, and his colleagues at Harvard University have looked at neural activity associated with the creation of false memories. Previous studies had focused on neural activity associated with the retrieval of false memories.

Relying upon earlier work that showed the right fusiform cortex is involved in encoding the exact visual details of objects and the left fusiform cortex is involved in more general processing, Schacter’s group designed an experiment to test the role of the right fusiform area in avoiding the formation of false memories for objects similar to those seen previously but not exactly the same.

In the study, led by graduate student Rachel Garoff, participants underwent brain scans using fMRI as they made judgments about the size of various objects. A surprise memory test was then given when the patients were outside the MRI scanner. During the test, patients saw objects identical to those seen earlier, objects similar to those they had seen earlier, and new objects they had not seen at all.

Although the study is still in progress, results to date indicate that the right fusiform area was more active in these individuals during the encoding of objects participants later labeled the “same” as objects they had seen before. The right fusiform area was less active when patients incorrectly labeled objects the same when they were only similar, or when they labeled objects similar when they were actually the same.

“This preliminary finding supports the idea that the right fusiform area is tied to the encoding of specific visual details,” Schacter said. “It also suggests that false memories of objects can be reduced through additional activity of the right fusiform area during encoding.”

In another study, Schacter’s group showed that visual processing regions of the brain were reactivated during true memory but not during false memory.

Scott Slotnick and Schacter constructed “prototype” shapes by adjoining four curves into various shapes, then they distorted these prototypes to form “exemplar” shapes. The twelve individuals who have taken part in the study thus far were instructed to remember each shape and whether it appeared to the left or the right on a screen. “True memory” was defined as recognizing a shape that was seen previously, and “false memory” referred to mistakenly recognizing a shape that resembled a shape seen earlier but that was not actually seen. In the next step, fMRI was used to determine which areas of the brain were associated with true and false memory.

“We found that participants gave the same response regarding whether an object was “new” or “old” during true and false memory, which leads you to expect that the associated brain activity might be indistinguishable,” Schacter said. “But fMRI revealed there is a different activation of brain regions involved in visual processing during true versus false memory. What we need to do now is understand the meaning of this difference.”

This is not as impressive as it first sounds. The researchers can not say in each instance whether the memory being recalled is true or false. They only see a difference on average over many experimental runs.

However, Schacter points out that their work currently averages brain activity over many trials, so detecting the accuracy of a single memory is not yet possible.

Still, these experiments suggest that it might be possible to train people to be more aware of the strength of their own memory recall. If there are differences in brain activity when recalling accurate and inaccurate matches between viewed images and memory it might be possible to develop a training regime to let people know when they are making fake matches between memories and viewed objects. By getting that immediate feedback people might be able to calibrate their own sense of certainty and develop a better sense of just how strong the feeling of seeing a match has to be in order for it to be likely to be accurate.

By Randall Parker    2003 November 10 02:49 PM   Entry Permalink | Comments (3)
2003 July 28 Monday
Music Instrument Training Improves Verbal, Not Visual Memory

Musical training might be a form of exercise for the left brain.

Students with musical training recalled significantly more words than the untrained students, and they generally learned more words with each subsequent trial of three. After 30-minute delays, the trained boys also retained more words than the control group. There were no such differences for visual memory. What's more, verbal learning performance rose in proportion to the duration of musical training.

We need to better organize our left brains.

The researchers, led by Dr Agnes Chan, said giving music lessons to children "somehow contributes to the reorganization [and] better development of the left temporal lobe in musicians, which in turn facilitates cognitive processing mediated by that specific brain area, that is, verbal memory."

But the study did not randomly assign its subjects.

But Nora Newcombe, a psychology professor at Temple University in Philadelphia, says there are two major flaws in the new study. The students were not randomized to the music and non-music groups, they were "self-selected," she points out. And, she adds, "It shows nothing [in a study] when you self-select."

Still, the fact that the same people experienced a change in only one type of memory is strongly suggestive that a real effect was found. This is likely to lead to even more attempts by parents to get their kids to take music lessons. But would it help an adult to first take up music lessons in adulthood?

By Randall Parker    2003 July 28 10:22 AM   Entry Permalink | Comments (0)
2003 July 13 Sunday
Learning Blocked In Mice Deprived Of Sleep For 5 Hours

You have to sleep to learn.

PHILADELPHIA -- Scientists at the University of Pennsylvania have found new support for the age-old advice to "sleep on it." Mice allowed to sleep after being trained remembered what they had learned far better than those deprived of sleep for several hours afterward.

The researchers also determined that the five hours following learning are crucial for memory consolidation; mice deprived of sleep five to 10 hours after learning a task showed no memory impairment. The results are reported in the May/June issue of the journal Learning & Memory.

"Memory consolidation happens over a period of hours after training for a task, and certain cellular processes have to occur at precise times," said senior author Ted Abel, assistant professor of biology at Penn. "We set out to pinpoint the specific window of time and area of the brain that are sensitive to sleep deprivation after learning."

Abel and his colleagues found that sleep deprivation zero to five hours after learning appeared to impair spatial orientation and recognition of physical surroundings, known as contextual memory. Recollection of specific facts or events, known as cued memory, was not affected. Because the brain's hippocampus is key to contextual memory but not cued memory, the findings provide new evidence that sleep helps regulate neuronal function in the hippocampus

What conclusions can be drawn from this aside from that it is wise to get a full night of sleep? One possibility is that if you can choose when to study then it might help more to study in the evening in the last 5 waking hours before you go to bed. Best to have freshly learned information in your mind before going to sleep.

One problem with this advice is that schools typically teach classes during the day. If you really want to get radical in your approach to learning one possibility to consider is to wake up and go to bed much earlier. One could learn during the day and then immediately go to sleep for the evening hours. Then wake up in the early hours of the new day to start your day's activities. This isn't practical for most people. But if you are going to work your way thru college it might make more sense to have a job that starts at midnite and then stay awake at work until it is time for your morning classes. Then go to school and then come home and go to sleep.

A much less radical approach which would allow one to keep regular hours would be to do all the non-study activities (chores, errands, jobs, etc) before evening time and reserve all evening hours for studying.

An afternoon siesta might well help the learning process as well.

By Randall Parker    2003 July 13 05:20 PM   Entry Permalink | Comments (4)
2003 January 27 Monday
Neurofeedback Trains Minds To Improve Memory

If you don't want to look at gory pictures as a way to improve your memory there is a less disturbing technique available.

Scientists believe they may have found a way to improve our memory by as much as 10%.

Researchers at Imperial College London have used a technique called neurofeedback to train people to remember more clearly.

It works by showing people their own brainwaves on a computer screen, and teaching them how to control them.

By Randall Parker    2003 January 27 10:10 AM   Entry Permalink | Comments (2)
2003 January 04 Saturday
Consolidated Memories Are Erasable In Rats

45 day old memories in rats were called up by an environmental stimulus and then erased.

In the Neuron article, Dr. Nader and his colleague from New York University extended this work to the part of the memory system that contributes to mediating conscious or declarative memories, called the hippocampus. They conditioned rats to fear the environment in which they were (i.e. a small box) by inducing a light electric shock on their paws.

This paradigm engaged the hippocampus to process information about the context that can be used to predict shock. The hippocampal contributions to this paradigm are thought to engage similar processes as declarative memories in humans. "According to the cellular theory of memory, new memories require new protein synthesis to be stored," explains Dr Nader.

"The hippocampus also has a second level of consolidation called systems consolidation theory. This posits that the hippocampus has a time-limited role in memory storage, after which the memory is independent of the hippocampus. This is why amnesiacs such as H.M. (the patient of neuropsychologist Brenda Milner) who have damage to their hippocampus can remember events that happened a few years ago but can't remember recent events."

Before testing cellular reconsolidation in the hippocampus, professors Nader and Ledoux showed that intra-hippocampal infusions of the protein synthesis inhibitor anisomycin caused amnesia for a consolidated hippocampal-dependant contextual fear memory, but only if the memory was reactivated prior to infusion. "This demonstrated that memories stored in the hippocampus can undergo cellular reconsolidation or restorage," said Dr. Nader. "Surprisingly, the effect occurred even if reactivation was delayed for 45 days after training, a time when declarative memory is independent of the hippocampus. In fact, we found that if you lesion the hippocampus 45 days after conditioning, there is no effect. Therefore the memory of the context has to be independent of the hippocampus. However, if the memory is now reactivated immediately prior to lesions, there is a large effect. Thus, mature old memories stored in our cortex return to being dependent on the hippocampus after they are reactivated, an instance of systems reconsolidation."

Consider the implications if this can be made to work for humans. Traumatic memories could be erased. Is that good or bad? It seems a scary prospect. But also memories of crime could be erased and a perpetrator could claim in all honesty to have no memory of having committed a particular act. Even more nefarious uses of such a technique could be imagined. A criminal or a government could force someone to recall a memory that they don't want a person to have and then erase it.

By Randall Parker    2003 January 04 02:08 PM   Entry Permalink | Comments (1)
2002 November 10 Sunday
Gory Pictures Improve Memory Retention

This result suggests that college students should sit and watch parts of slasher movies interleaved with reading textbooks and class notes:

Nielson asked 32 people to memorize a list of words, such as fire, queen and butterfly. Half of them then watched a film of a full dental extraction, complete with blood and screeching drill. "It was nasty - it made you crawl," she says.

24 hours later, the traumatized subjects' word memory was around 10% better than that of those who'd sat through a dull video on tooth brushing. Emotion helps us remember, concludes Nielson, "but it doesn't have to be [personally] meaningful".

The next obvious round of experiments would be to use hormones such as adrenaline to try to see if the same mental state caused by watching the dental extraction can be invoked pharmacologically. The explanation for this might be that excitement increases the release of some hormones or neurotransmitters than, in turn, stimulate the division of neural stem cells in the hippocampus.

By Randall Parker    2002 November 10 12:35 PM   Entry Permalink | Comments (9)
2002 November 05 Tuesday
Modafinil Boosts Human Mental Abilities

Modafinil improves the mental functioning of healthly volunteers:

Danielle Turner, from the Department of Psychiatry at the University of Cambridge, says modafinil could revolutionise current understanding of the way we form and retain memories. It seems to have a unique mechanism of action in the brain.

"In the study, the volunteers given modafinil performed significantly better at neuropsychological tests involving short-term memory and showed less impulsive responding and an increased tendency to reflect on the tasks they were given," she said.

Modafinil provided this benefit without the side effects seen with amphetamines and other drugs:

Sixty healthy young men were tested using touch-sensitive computer screens and easy-to-understand computer games after they were given either a dummy tablet or modafinil.

The ones on modafinil showed improved ability in planning complex problems, recalling longer strings of numbers and remembering abstract patterns.

Modafinil is available as Provigil and is used to treat narcolepsy (uncontrollable sleepiness). Read more about modafinil here and here and also here as Provigil. You can also read an ABC News article on modafinil as well this article which includes mention of military uses for modafinil.

By Randall Parker    2002 November 05 12:35 PM   Entry Permalink | Comments (1)
2002 October 31 Thursday
Development Of Memory In Human Babies

When humans are born their brains are not capable of forming recallable memories. The sequence of the development of mental capabilities is being studied more closely:

Six-month-olds have a memory span of no more than about 24 hours, which gradually expands to up to a month by 9 months. In the new study, 13-month-old babies could not remember events they had witnessed and mimicked four months earlier -- a task that came easily to their elders, ages 21 months and 28 months.

The findings support the view that at 9 months, two key areas of the brain involved in learning and memory are not yet fully mature. These are the hippocampus, a region where memories are first processed before being transferred to the cerebral cortex for permanent storage, and the frontal cortex. This large anterior area of the brain is involved in reasoning, planning, abstract thought and other complex cognitive processes in addition to motor functions, such as speech, handwriting, drawing, walking, reaching and grasping.

By Randall Parker    2002 October 31 09:49 PM   Entry Permalink
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