August 10, 2008
Facial Expression Reactions Influenced By Gene CREB1

Reaction to different forms of facial expressions seems to be influenced by a gene which also plays a role in governing risk of suicidal thinking.

In 2001, Breiter collaborated with Daniel Kahneman, PhD, of Princeton University and Peter Shizgal, PhD, Concordia University, Montreal, to show how the brain's reward/aversion circuitry followed the principles of what is called prospect theory when responding to the anticipation and receipt of a financial reward, helping to lay the groundwork for the field now called neuroeconomics. Kahnemann was a co-recipient of the 2002 Nobel Prize in economics for his earlier development of prospect theory, which describes the different ways people evaluate positive and negative outcomes in uncertain situations.

The current report connects molecular genetics with earlier studies of choice and preference and with investigations of the brain's reward circuitry. The researchers focused on a gene called CREB1 that has been implicated in animal studies of the brain's reward/aversion function. Study lead author Roy Perlis, MD, medical director of the MGH Bipolar Program, and colleagues previously found that depressed men with a particular variation near the gene coding for CREB report greater difficulty suppressing anger. Another study of theirs associated the same variation with a threefold greater risk of suicidal thinking in major depressive disorder patients soon after beginning antidepressant therapy. The 28 participants in the current study had no evidence of any psychiatric disorder or physical disorder that might influence brain activity.

Willingness to view expressions of different emotions seems influenced by which version of CREB1 you have.

In addition to analyzing each participant's version of the CREB1 gene, the researchers conducted a set of experiments. As the participants viewed facial expressions reflecting different emotional states happy, neutral, sad, fearful and angry fMRI scans were taken to examine the activity of brain structures associated with processing pleasant or unpleasant experiences. In another test, participants viewed the same pictures and could change how long they viewed an image by the way they pressed keys on a keyboard. Many earlier studies have established the keypress experiment as a quantitative measure of preference. In the version used in this study, keypress responses reflected participants' judgment and decisions about how much or how little they preferred the facial expressions.

The fMRI study showed that, during the viewing of angry faces, the activity of a structure called the insula, involved in the response to unpleasant situations, depended on which version of the CREB1 gene a participant inherited. In the keypress experiment, responses indicating a preference against the angry expression paralleled the CREB1-affected fMRI activity seen in the insula in the first experiment and also differed depending on the CREB1 variant that had been inherited.

This one gene accounts for 20% of the differences seen in how people chose options in response to the facial expressions.

"We were surprised to see that variation in the CREB1 gene would account for more than 20 percent of the difference in how healthy participants weighed different options and expressed specific preferences," says Perlis. "Our previous studies and the work of other groups suggested that variation in this gene could be important for judgment and decision-making by the brain, but we needed to connect this to a measurable decision-making effect in both behavior and brain activity."

If more genes exist which influence how people react then future discoveries will leave even less room for free will. This process of discovery will repeat for more genes and more aspects of human behavior. These researchers are already looking into other genes which might influence thought and behavior.

Breiter adds, "This study connects quantitative measurements across three levels of observation brain activity, genomic variation and the expression of preference. We now are investigating the potential role of other genes and will go on to assess how this relationship across three levels of observation may be affected by conditions such as depression and addiction."

Update: The more our personalities are found to be determined by genes the more human nature will change once selection of genes for offspring (basically offspring genetic engineering) becomes possible. People are bound to make some decisions for offspring genes that are different than what the offspring would get naturally. If people become empowered to make decisions that change a large variety of cognitive characteristics then they will make those decisions. What decisions will they make? That is one of the biggest questions we face about the future of humanity.

If you could get into a time machine and pop out 100 years in the future would you find the personalities you meet congenial? Enjoyable to be around? Cut-throat? Amoral? Extremely pushy and aggressive? Will something resembling civil society still exist? Will humans live in enormous tension with each other? The genetic variations exist to make all these outcomes possible. Which outcomes occur (and the answer may differ by country, religion, social class, etc) will be determined by the genetic choices people make for their offspring.

Share |      Randall Parker, 2008 August 10 10:05 PM  Brain Genetics


Comments
Ramez Naam said at August 10, 2008 11:02 PM:

You remain insightful, Randall. Thanks for continuing to filter the science news and provide informed commentary.

G said at August 11, 2008 4:36 AM:

Randall, you wrote, "If more genes exist which influence how people react then future discoveries will leave even less room for free will." What is this "free will" you speak of? Seriously, just as I see proof of evolution everywhere each and every day, I also see proof of a predetermined life. I've only had one philosophy class in my life and haven't ever done any research (so maybe I'm way off base and a complete idiot) but I just don't see how we can possibly have free will. Does a cat have free will? How about a chimp? A human newborn? A human 7 year old? An 15 year old? An adult with ADHD? An adult with Down Syndrome? Any adult at all? At best, someone can argue that we have very limited free will, but I still don't buy it. Just because our entire society (religion, morals/ethics, education, punishment and on and on) is built on the idea of free will, doesn't make it so. It does, however, make me sound like a fringe crackpot!

Nonetheless, another interesting article with your usual insightful comments (which are often as good as or better than the original articles!).

Xenophon Hendrix said at August 11, 2008 11:07 AM:

I just came up with a little thought experiment:

Suppose I find I have a gene variation that makes it harder for me to suppress anger. Suppose I would just as soon not have this variation.

Next, suppose that researchers develop a drug that alleviates this anger-suppression problem.

If I decide to start taking this drug, is my decision an incidence of free will?

Vicente Cueto said at August 11, 2008 11:13 AM:

All so called free will relays in the fact that decisions of a human being are made on the base of previous experiences.
If the fact that is to be evaluated in the present is similar to some negative memory, the person shall reject that fact. So, free will would be also be more limited considering that most of our choices are based in patterns set in the brain from the past of the person.
If such neuronal circuits provoke a conduct of reaction towards something in the environment, that person shall avoid that environment.
Genes and the subconcious narrow even more the pathway of "FreeWill".
Meditation concepts: If I ease the body, then I easy the mind as Ive been told (full of thoughts that we dont control and that could be related to genes) whats remaining is the free will?

Randall Parker said at August 11, 2008 6:19 PM:

G,

It is the public at large that believes in free will. I frankly can't see how it can work either. One has to believe in the Ghost In The Machine. Most people do. Even a lot of left-liberal secularists believe a form of genetic Cartesian dualism where the mind has somehow risen above the genetic code that created it.

I write posts like this one in part to hammer home what is still a minority viewpoint about human nature.

Fringe crackpot: Yes, you and I are on the fringe. I used to be bothered by this. But I've pretty much made my peace with my fringe status as a thinker with my mental model of humanity.

Post a comment
Comments:
Name (not anon or anonymous):
Email Address:
URL:
Remember info?

                       
Go Read More Posts On FuturePundit
Site Traffic Info
The contents of this site are copyright