Activation of ventral striatum during anticipation of reward – A pilot study using functional magnetic resonance imaging for a future experiment about psychopathy.

2017-05-22T07:53:22Z (GMT) by Daniel Samsami
<i>Introduction: </i>Psychopathy is a problem at both the individual and societal level. The mechanisms in the brain that underlie psychopathic traits are not yet fully known. Hyperreactivity of the brain's reward system, specifically in the ventral striatum, has been identified as a possible contributing factor in previous studies. Monetary incentive delay task (MIDT) is an experimental paradigm used to examine the brain's reward system which causes increased activation of the ventral striatum during anticipation of reward. <i>Aims: </i>This pilot study aimed to set up an experimental paradigm by using MIDT and test if it led to increased activation of the ventral striatum during anticipation of reward, and to calculate the statistical power for future experiments on patients with psychopathy. <i>Materials and methods:</i> Nine healthy male volunteers were enrolled and underwent an experiment with MIDT as paradigm while they were investigated at the same time by functional magnetic resonance imaging (fMRI). <i>Results: </i>Four subjects were available for analysis. Activation of the ventral striatum during reward anticipation was estimated to be Cohen's <i>d = </i>1.02, <i>p</i> = 0.13. using a <i>t</i>-test on data extracted from fMRI images but was not statistically significant. <i>Conclusions:</i> We could replicate previous findings that anticipation of reward leads to increased blood flow into the ventral striatum, but the results are uncertain. To achieve reasonable strength in future experiments approximately 60 subjects are required in each group with a power difference of 50% between each group.