title: Levodopa administration modulates striatal processing of punishment-associated items in healthy participants.
abstract: BACKGROUND
  Appetitive and aversive processes share a number of features such as their relevance for action and learning. On a neural level, reward and its predictors are associated with increased firing of dopaminergic neurons, whereas punishment processing has been linked to the serotonergic system and to decreases in dopamine transmission. Recent data indicate, however, that the dopaminergic system also responds to aversive stimuli and associated actions.
  
  
  OBJECTIVE
  In this pharmacological functional magnetic resonance imaging study, we investigated the contribution of the dopaminergic system to reward and punishment processing in humans.
  
  
  METHODS
  Two groups of participants received either placebo or the dopamine precursor levodopa and were scanned during alternating reward and punishment anticipation blocks.
  
  
  RESULTS
  Levodopa administration increased striatal activations for cues presented in punishment blocks. In an interaction with individual personality scores, levodopa also enhanced striatal activation for punishment-predictive compared with neutral cues in participants scoring higher on the novelty-seeking dimension.
  
  
  CONCLUSIONS
  These data support recent indications that dopamine contributes to punishment processing and suggest that the novelty-seeking trait is a measure of susceptibility to drug effects on motivation. These findings are also consistent with the possibility of an inverted U-shaped response function of dopamine in the striatum, suggesting an optimal level of dopamine release for motivational processing.
authors.affiliation: Helen Wills Neuroscience Institute, University of California, Berkeley, CA, 94720, USA, bianca.wittmann@psychol.uni-giessen.de.
authors.forename: Bianca C
authors.initials: BC
authors.lastname: Wittmann
authors.forename: Mark
authors.initials: M
authors.lastname: D'Esposito
mesh_terms: D000328:Adult; D004298:Dopamine / Q000378:metabolism; D004311:Double-Blind Method; D005260:Female; D064368:Healthy Volunteers / Q000523:psychology*; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009042:Motivation / Q000187:drug effects / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011678:Punishment / Q000523:psychology*; D012201:Reward; D066328:Ventral Striatum / Q000187:drug effects* / Q000378:metabolism*; D055815:Young Adult
chemical_list: D007980:Levodopa; D004298:Dopamine