If an individual receives more or less reward than expected or more or less punishment than expected,
this generates a prediction error; the greater the difference between prediction and reality, the greater the prediction error. Prediction errors are critical for reinforcement-based learning. The greater the prediction error, the faster the system will attempt to learn the new value of the Inhibitors,research,lifescience,medical stimulus or action.52 However, this third impairment will not be considered in any further detail here as the data supporting its existence is obtained with youth with psychopathic traits.53 The relevant studies have yet to be done in adults with psychopathy. Psychopathy: the neural profile Inhibitors,research,lifescience,medical Both structural and functional magnetic
resonance imaging studies can inform an account of psychopathy. We will briefly consider the current state of the literature regarding these studies. Note though that only studies where groups were matched for IQ will be considered. The importance of appropriate matching can be seen from the data presented in a recent sMRI study.54 This study reported a 30% reduction across much of cortex in adults with psychopathy relative to healthy Inhibitors,research,lifescience,medical comparison individuals.54 However, these results were only seen when comparing individuals with psychopathy with healthy comparison individuals. The IQ and, for that matter, the substance dependence rates of these comparison individuals, Inhibitors,research,lifescience,medical was not reported but it is likely, given their job descriptions (students, hospital staff, and skilled workers), that their average IQ was significantly higher and their average substance dependence rate was significantly lower than those of the patients. These confounds may have driven the findings. This suggestion is supported from the authors’ data on only the patients. Groups of patients with high psychopathy vs low psychopathy scores, matched for IQ, showed very minimal differences in cortical volume.54 sMRI studies A series of findings, reported across labs where appropriate IQ comparisons have been made, are worth noting. Not all studies have reported reduced Inhibitors,research,lifescience,medical volumes in these regions in psychopathy but none (at least involving IQ matched
samples) have reported increased volumes in these regions. Thus, three studies have reported reduced amygdala volumes in adults with psychopathy55-57including the largest structural imaging study of this population to date (N=296).55 Similarly, four studies have check reported reductions in temporal PD98059 mw pole55,58-60 and two in STS.58,61 Three studies have reported reductions in orbitofrontal cortex.55,58,61 Moreover, and interestingly given the extensive connections between the amygdala and orbitofrontal cortex though the uncinate fasciculus white matter tract, all three DTI studies examining the structural integrity of this tract in individuals with psychopathy have reported reduced structural integrity relative to comparison individuals.