October 31, 2004
Electric Current To Scalp Improves Speed Of Word Recall

Meenakshi Iyer, Ph.D. of the US National Institute of Neurological Disorders and Stroke Brain Stimulation Unit has found that a two thousandths of an ampere applied to scalps using electrodes increases the speed of word recall.

A current of two thousandths of an ampere (a fraction of that needed to power a digital watch) applied for 20 minutes is enough to produce a significant improvement, according to data presented this week at the annual meeting of the Society for Neuroscience, held in San Diego.


The volunteers were asked to name as many words as possible beginning with a particular letter. Given around 90 seconds, most people get around 20 words. But when Iyer administered the current, her volunteers were able to name around 20% more words than controls, who had the electrodes attached but no current delivered. A smaller current of one thousandth of an amp had no effect.

This result is not a strong case for using electric currents to improve your brain's performance. First of all, I'm not convinced that this is entirely harmless. The current flows are causing events in the brain that otherwise would not occur. Are all the effects transitory? We do not know.

Also, the improvement in performance in one kind of test may very well decrease performance in other kinds of tests. There are precedents for this. For example, caffeine helps the brain stay on a chain of thought but does so at the expense of reducing word recall on unrelated subjects. Well, the ability to stay on a chain of thought is obviously useful in a lot of situations and so the trade-off is often worth it. But what is the trade-off from having the ability to recall more words that start with the same letter? Iyer's work needs to be repeated with a larger assortment of tests of cognitive function to see if there is any decay in the ability to perform other types of mental tasks.

Also, a wider range of cognitive tests run on people who take this treatment might turn up other benefits of this treatment. Perhaps the ability to recall more words improves the ability to find words to use to write better prose. People who do a lot of writing such as reporters, book authors, and Hollywood script writers might benefit from a little bit of electric juice. But another question that needs to be answered is just how long does the effect last?

My advice is to go jogging if you have hit a mental writing block. Exercise will increase brain performance while fat and table sugar will probably decrease brain performance.

Update: My point above about there often being trade-offs for improving cognitive enhancement is driven home by a new report out of Ohio State University that stress increases memory recall but decreases problem solving ability.

Researchers at Ohio State University gave a battery of simple cognitive tests to 19 first-year medical students one to two days before a regular classroom exam a period when they would be highly stressed. Students were also given a similar battery of tests a week after the exam, when things were less hectic.

While pre-exam stress helped students accurately recall a list of memorized numbers, they did less well on the tests that required them to consider many possibilities in order to come up with a reasonable answer. A week after the exam, the opposite was true.

"Other studies have suggested that elevated stress levels can actually improve some aspects of cognition, particularly working memory," said Jessa Alexander, a study co-author and a research assistant in neurology at Ohio State. "The results of the two problem-solving tests we administered suggested a decline in problem solving abilities that required flexible thinking."

She conducted the study with David Beversdorf, an assistant professor of neurology at Ohio State. The two presented their findings on October 25 in San Diego at the annual Society for Neuroscience conference.

Share |      Randall Parker, 2004 October 31 12:17 PM  Brain Enhancement

Jussi said at November 1, 2004 12:27 AM:

Why are they using electric current instead of TMS, which i would asume to be much more effective and less painful?

Engineer-Poet said at November 1, 2004 5:44 AM:

TMS, which requires a time-varying magnetic field, cannot apply a direct-current stimulus.

This goes back to Faraday's law of induction: del cross E = -dB/dt

Phil said at November 1, 2004 7:28 PM:

"A current of two thousandths of an ampere (a fraction of that needed to power a digital watch). . . ". Actually, 2 milliamps is a lot more than a digital watch requires to operate. I wonder if they mean 2 microamperes?

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