title: The effect of acute tryptophan depletion on the BOLD response during performance monitoring and response inhibition in healthy male volunteers.
abstract: BACKGROUND
  Serotonin (5-HT) was implicated in both clinical and experimental studies in flexible, goal-directed behavior. However, the way in which 5-HT manipulations affect brain activation patterns underlying different subprocesses of cognitive flexibility remains largely unknown.
  
  
  OBJECTIVE
  The aim of this study was to investigate the effect of a transient lowering of 5-HT on brain activation during performance monitoring and response inhibition.
  
  
  METHODS
  We used acute tryptophan depletion (ATD), a well-known method to reduce central 5-HT, to investigate the effect of a transient lowering of 5-HT on the blood-oxygen-level dependent (BOLD) response in an event-related functional MRI study. Thirteen healthy male volunteers performed a modified Go/NoGo task in a counterbalanced, placebo-controlled, within-subject design.
  
  
  RESULTS
  ATD significantly lowered plasma tryptophan but did not affect mood and cognitive performance. ATD decreased the BOLD response in the dorsomedial prefrontal cortex (BA 8) during performance monitoring. ATD did not affect the BOLD response during response inhibition.
  
  
  CONCLUSIONS
  This study provides more evidence for the suggested role of 5-HT in performance monitoring. Because ATD studies have revealed inconsistent effects of ATD on performance and on brain activation, it was suggested that gender and personality traits are important variables to take into account for future research.
authors.affiliation: Department of Psychiatry and Neuropsychology (DRT 10), Brain and Behavior Institute, Maastricht University, P.O. Box 616, 6200 MD Maastricht, Netherlands. l.evers@np.unimaas.nl
authors.forename: Elisabeth A T
authors.initials: EA
authors.lastname: Evers
authors.forename: Frederik M
authors.initials: FM
authors.lastname: van der Veen
authors.forename: Jeroen A
authors.initials: JA
authors.lastname: van Deursen
authors.forename: Jeroen A J
authors.initials: JA
authors.lastname: Schmitt
authors.forename: Nicolaas E P
authors.initials: NE
authors.lastname: Deutz
authors.forename: Jelle
authors.initials: J
authors.lastname: Jolles
mesh_terms: D000328:Adult; D000339:Affect / Q000502:physiology; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D018592:Cross-Over Studies; D004193:Discrimination Learning / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology; D004311:Double-Blind Method; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011340:Problem Solving / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012701:Serotonin / Q000502:physiology*; D014364:Tryptophan / Q000172:deficiency*
chemical_list: D012701:Serotonin; D014364:Tryptophan; D010100:Oxygen