Featured Published Manuscript of the Month: October 2017
Chosen and summarized by: William J. Denomme
Hosking, J.G., Kastman, E.K., Dorfman, H.M., Samanez-Larkin, G.R., Baskin-Sommers, A., Kiehl, K.A … Buckholtz, J.W. (2017). Disrupted prefrontal regulation of striatal subjective value signals in psychopathy. Neuron, 95, 221-231. doi: 10.1016/j.neuron.2017.06.030
Corresponding Authors: Jay G. Hosking ([email protected]), Department of Psychology, Harvard University; Joshua W. Buckholtz ([email protected]), Department of Psychology and Center for Brain Science, Harvard University
The current study utilized a multi-modal neuroimaging approach to assess the neural basis of maladaptive decision-making in psychopathic individuals. The researchers acquired resting-state scans and task-related fMRI whole-brain images from 49 male incarcerated offenders (mean age = 31, IQ > 70) who completed a delay-discounting task while placed in a fMRI scanner. Psychopathic traits were measured using the Hare Psychopathy Checklist-Revised (PCL-R). As the nucleus accumbens (NAcc) is thought to be a primary neural hub in reward processing, and the ventromedial prefrontal cortex is thought to be a mediator of this reward processing to as to use the reward information to make advantageous and rational goal-directed decisions, the authors assessed correlations between psychopathic traits and offending patterns and subjective-value processing in the NAc and the resting-state connectivity between these the NAcc and VMPFC.
A few key findings were:
· PCL-R scores, Factor 1 and Factor 2 scores were positively correlated with the subjective value-related NAcc neural activity.
· Subjective-value related NAcc activity was negatively correlated with resting-state functional connectivity between the VMPFC and NAcc, suggesting that reduced connectivity between the NAcc and VMPFC could hinder the ability for the VMPFC to regulate NAcc activity, leading to greater NAcc correlating with the subjective value of the rewards.
· PCL-R scores, Factor 1 and Factor 2 scores were negatively correlated with resting-state functional connectivity between the VMPFC and NAcc, suggesting that psychopathic traits are associated with a greater inability for the VMPFC to regulate NAcc activity and a sensitized NAcc response to the subjective value of a reward.
· Higher subjective value-related NAcc activity was positively correlated while resting-state VMPFC-NAcc was negatively correlated with the total number of convicted crimes.
Some key implications:
· This study demonstrated network-level neural abnormalities correlating with psychopathic traits that may account for decision-making impairments in psychopathy. The results of this study provide a neurological underpinning for the increased reward sensitivity, impulsive decision-making, and increased risk-taking behavior, and lack of consequence consideration in psychopathic individuals.
· The fact that both Factor 1 and Factor 2 traits were associated with these abnormal neural processing and functional connectivity patterns suggests that decision-making, risk-taking, reward sensitivity and impulse control deficits are difficult to attribute to a single factor of psychopathy, and that interpersonal, affective, lifestyle and antisocial deficits in psychopathy may promote this disruptive and harmful lifestyle to oneself and to others.
· The results of this study warrant further research on the directionality of the connectivity between the VMPFC and the NAcc in psychopathic individuals. Applying different technologies that could delineate the direction of connection between the VMPFC and NAcc in psychopathy, such as positron emission tomography and magnetic resonance spectroscopy, could reveal whether the VMPFC is demonstrating deficits in neurotransmission to the NAcc to regulate subjective value processing and goal-directed decision-making.