title: Intermittent Theta Burst Stimulation Increases Reward Responsiveness in Individuals with Higher Hedonic Capacity.
abstract: BACKGROUND
  Repetitive transcranial magnetic stimulation over the left dorsolateral prefrontal cortex (DLPFC) has been documented to influence striatal and orbitofrontal dopaminergic activity implicated in reward processing. However, the exact neuropsychological mechanisms of how DLPFC stimulation may affect the reward system and how trait hedonic capacity may interact with the effects remains to be elucidated.
  
  
  OBJECTIVE
  In this sham-controlled study in healthy individuals, we investigated the effects of a single session of neuronavigated intermittent theta burst stimulation (iTBS) on reward responsiveness, as well as the influence of trait hedonic capacity.
  
  
  METHODS
  We used a randomized crossover single session iTBS design with an interval of 1 week. We assessed reward responsiveness using a rewarded probabilistic learning task and measured individual trait hedonic capacity (the ability to experience pleasure) with the temporal experience of pleasure scale questionnaire.
  
  
  RESULTS
  As expected, the participants developed a response bias toward the most rewarded stimulus (rich stimulus). Reaction time and accuracy for the rich stimulus were respectively shorter and higher as compared to the less rewarded stimulus (lean stimulus). Active or sham stimulation did not seem to influence the outcome. However, when taking into account individual trait hedonic capacity, we found an early significant increase in the response bias only after active iTBS. The higher the individual's trait hedonic capacity, the more the response bias toward the rich stimulus increased after the active stimulation.
  
  
  CONCLUSIONS
  When taking into account trait hedonic capacity, one active iTBS session over the left DLPFC improved reward responsiveness in healthy male participants with higher hedonic capacity. This suggests that individual differences in hedonic capacity may influence the effects of iTBS on the reward system.
authors.affiliation: Department of Psychiatry and Medical Psychology, Ghent UniversityGhent, Belgium; Department of Psychiatry and Experimental Psychology, Ghent Experimental Psychiatry Lab, University of GhentGhent, Belgium.
authors.forename: Romain
authors.initials: R
authors.lastname: Duprat
authors.affiliation: Department of Experimental Clinical and Health Psychology, Ghent University Ghent, Belgium.
authors.forename: Rudi
authors.initials: R
authors.lastname: De Raedt
authors.affiliation: Department of Psychiatry and Medical Psychology, Ghent University Ghent, Belgium.
authors.forename: Guo-Rong
authors.initials: GR
authors.lastname: Wu
authors.affiliation: Department of Psychiatry and Medical Psychology, Ghent UniversityGhent, Belgium; Department of Experimental Clinical and Health Psychology, Ghent UniversityGhent, Belgium; Department of Psychiatry, University HospitalBrussels, Belgium.
authors.forename: Chris
authors.initials: C
authors.lastname: Baeken
keywords: anhedonia; dorsolateral prefrontal cortex; iTBS; probabilistic learning; reward processing; reward sensitivity; theta burst stimulation