Reconciling the Role of Serotonin in Behavioral Inhibition and Aversion: Acute Tryptophan Depletion Abolishes Punishment-Induced Inhibition in Humans

• DOI: 10.1523/jneurosci.2513-09.2009
• Publication Date: 2009-09-23T17:30:28Z
• Authors: Molly J. Crockett; Luke Clark; Trevor W. Robbins
• Keywords: Punishment (psychology); Aversive Stimulus; Escape response; Behavioral inhibition

The neuromodulator serotonin has been implicated in a large number of affective and executive functions, but its precise contribution to motivation remains unclear. One influential hypothesis aversive processing; another proposed more general role for behavioral inhibition. Because inhibition is prepotent reaction outcomes, it challenge reconcile these two accounts. Here, we show that critical punishment-induced not overall motor response or reporting outcomes. We used acute tryptophan depletion temporarily lower brain healthy human volunteers as they completed novel task designed obtain separate measures inhibition, sensitivity After placebo treatment, participants were slower respond under punishment conditions compared with reward conditions. Tryptophan abolished this without affecting the ability adjust bias line contingencies. magnitude reduction depended on degree which reduced plasma levels. These findings extend clarify previous research processing fit current theorizing involvement predicting