July 06, 2008
More Anxious Monkeys Have More Amygdala Activity

Rhesus monkeys that are more prone to anxiety have more activity in the amygdala part of the brain even when in a secure situation.

We all know people who are tense and nervous and can't relax. They may have been wired differently since childhood.

So if you are like the character "Tweak" in South Park you probably didn't get that way by drinking coffee. You just feel more stress and feel more nervous all the time. Blame it on your amygdala.

New research done by the HealthEmotions Research Institute and Department of Psychiatry at the School of Medicine and Public Health (SMPH) indicates that the brains of those suffering from anxiety and severe shyness in social situations consistently respond more strongly to stress and show signs of being anxious even in situations that others find safe.

Ned Kalin, chair of the UW-Madison Department of Psychiatry and director of the HealthEmotions Research Institute, in collaboration with graduate student Andrew Fox and others, has published a new study on anxious brains on the Public Library of Science (PLoS One) Web site today (July 2).

The study looked at brain activity, anxious behavior and stress hormones in adolescent rhesus monkeys, which have long been used as a model to understand anxious temperament in human children. Anxious temperament is important because it is an early predictor of the later risk to develop anxiety, depression and drug abuse related to self-medicating. The researchers found that those individuals with the most anxious temperaments showed higher activity in the amygdala, a part of the brain that regulates emotion and triggers reactions to anxiety, such as the fight or flight response. These anxious monkeys had more metabolic activity in the amygdala in both secure and threatening situations.

Suppose kids with anxious temperaments can be identified when they are 5 years old. Should anti-anxiety drugs be developed that are safe for long term use by children? Look at Ritalin use for hyperactive kids. Hyperactivity was probably adaptive in our nomadic past and therefore genes that cause it were selected for. Similarly, greater tendency to anxiety might have had adaptive value even as recently as a hundred years ago. But now in a modern context a greater tendency toward anxiety is maladaptive. Should children be given drugs that adapt them to modern industrial society?

Share |      Randall Parker, 2008 July 06 08:59 PM  Brain Stress

beowulf said at July 7, 2008 6:23 AM:

Before doping more kids up, perhaps encouraging daily meditation and exercise would be a better solution...

"Researchers at University of California San Francisco Medical Centre have found the practise [of Buddhist meditation] can tame the amygdala, an area of the brain which is the hub of fear memory.

They found that experienced Buddhists, who meditate regularly, were less likely to be shocked, flustered, surprised or as angry compared to other people."

And as psychiatrist John Ratey (author of "Spark" a new book about the mental health benefits of exercise) notes,

"Exercise also has a positive effect on the limbic system, because it helps regulate the amygdala. In the context of ADHD, the amygdala blunts the hair-trigger responsiveness a lot of people experience, and evens out the reaction to a new source of stimulus, so we donít go overboard and scream at another driver in a fit of road rage, for example."

Nick G said at July 7, 2008 10:33 AM:

It seems to me that researchers are still unconsciously in the grip of the old mind-body dualism.

Why else would they be surprised to find a correlation between a physical phenomenon (activity in the amygdala) and the experience of chronic anxiety? Why would they jump to conclusions about genetic sources of such chronic anxiety, just because they've identified a physical phenomenon in the body?

It's as if they still think there's a ghost in the machine. Why are they surprised when they find brain activity that correlates with emotions??

Sonny Moonie said at July 9, 2008 3:13 AM:

"Should children be given drugs that adapt them to modern industrial society?"

If those in charge of medicine want to use those children, to make them disposable worker-consumer units, docile, weak, and addicted to a lifetime of further medicines used to control them, yes, that rationale would be ideal for that purpose.

If there is any ruling class or a class that gets a good break in this industrial society and has a future, they won't be having their children drugged to be pacified and obedient in school. They would change the curriculum or form of school, to suit their children, such as allowing them more exercise and recesses to work off their excess energy, less anxious time sitting on buses and around more aggressive children. Certainly civilized life is artificial enough that it can be made to suit different natural temperaments, if there's the will.

Randall Parker said at July 9, 2008 8:40 PM:

Sonny Moonie,

Anxiety is not fun. This isn't just about making people obedient worker units. It is about avoiding painful depression, crippling anxiety, and diseases caused by chronic stress.

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