We show a behavioral advantage for the phylogenetically ancestral Val/Val genotype in an instrumental reversal learning task that requires rapid and flexible adaptation of decisions to changing reward contingencies in a dynamic environment...we discovered that a higher and more flexible learning rate underlies the advantage of the Val/Val genotype. Model-based fMRI analysis revealed that greater and more differentiated striatal fMRI responses to prediction errors reflect this advantage on the neurobiological level. Learning rate-dependent changes in effective connectivity between the striatum and prefrontal cortex were greater in the Val/Val than Met/Met genotype, suggesting that the advantage results from a downstream effect of the prefrontal cortex that is presumably mediated by differences in dopamine metabolism. These results show a critical role of dopamine in processing the weight a particular prediction error has on the expectation updating for the next decision.
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Monday, November 09, 2009
Genes that influence our adaptability to changing rewards
Krugel et al show that a genetic change that leads to replacement of the amino acid valine with methionine in an enzyme regulating brain dopamine levels alters the flexible adaptation of reward based learning.
Posted by Deric Bownds at 4:25 AM
Blog Categories: acting/choosing, memory/learning, motivation/reward
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