Friday, June 4, 2010

Why adolescents are crazy: part 2

I've written before about how adolescent brains differ from younger and older brains and how that affects behavior. Another group of researchers has found another difference.
Our results raise the hypothesis that these risky behaviors, such as experimenting with drugs or having unsafe sex, are actually driven by over activity in the mesolimbic dopamine system, a system which appears to be the final pathway to all addictions, in the adolescent brain.
The study had people from 8 to 30 classify images into two categories and paid them when they got it right.
Researchers measured so-called positive prediction error signals in the participants' brains  (or the difference between an expected outcome of an action and the actual outcome) as the participants discovered the results of their answers and the size of their rewards.
 "Learning seems to rely on prediction error because if the world is exactly as you expected it to be, there is nothing new to learn, " Poldrack said. Previous research has shown that the dopamine system in the brain is directly responsive to prediction errors. 
In other words, teenagers had the highest spikes in prediction error signals, so they probably had the biggest  spike in dopamine.

I don't doubt that all these researchers have identified biological correlates to teenage weirdness. On principle I doubt that any has found the sole cause. Everything is more complicated than you think it is.

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