Dayan, P and Huys, QJM (2008) Serotonin, inhibition, and negative mood. PLOS COMPUT BIOL , 4 (2) , Article e4. 10.1371/journal.pcbi.0040004.
Pavlovian predictions of future aversive outcomes lead to behavioral inhibition, suppression, and withdrawal. There is considerable evidence for the involvement of serotonin in both the learning of these predictions and the inhibitory consequences that ensue, although less for a causal relationship between the two. In the context of a highly simplified model of chains of affectively charged thoughts, we interpret the combined effects of serotonin in terms of pruning a tree of possible decisions, (i.e., eliminating those choices that have low or negative expected outcomes). We show how a drop in behavioral inhibition, putatively resulting from an experimentally or psychiatrically influenced drop in serotonin, could result in unexpectedly large negative prediction errors and a significant aversive shift in reinforcement statistics. We suggest an interpretation of this finding that helps dissolve the apparent contradiction between the fact that inhibition of serotonin reuptake is the first-line treatment of depression, although serotonin itself is most strongly linked with aversive rather than appetitive outcomes and predictions.
|Title:||Serotonin, inhibition, and negative mood|
|Open access status:||An open access publication|
|Publisher version:||http://www.ncbi.nlm.nih.gov/pmc/ articles/PMC2222921/?tool=pubmed|
|Keywords:||ACUTE TRYPTOPHAN DEPLETION, CENTRAL 5-HYDROXYTRYPTAMINE DEPLETION, GOAL-DIRECTED BEHAVIOR, NUCLEUS-ACCUMBENS, HEALTHY-VOLUNTEERS, CONDITIONED REWARD, TRANSPORTER GENE, DOPAMINERGIC ACTIVITY, ANTIDEPRESSANT ACTION, LEARNED HELPLESSNESS|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Life Sciences > Gatsby Computational Neuroscience Unit|
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