Morphometric correlation of impulsivity in medial prefrontal cortex

Abstract

Impulsivity is a complex behaviour composed of different domains encompassing behavioural dis-inhibition, risky decision-making and delay discounting abnormalities. To investigate regional brain correlates between levels of individual impulsivity and grey matter volume, we performed voxel-based morphometric correlation analysis in 34 young, healthy subjects using impulsivity scores measured with Barratt Impulsivity Scale-11 and computerized Kirby's delay discounting task. The VBM analysis showed that impulsivity appears to be reliant on a network of cortical (medial prefrontal cortex and dorsolateral prefrontal cortex) and subcortical (ventral striatum) structures emphasizing the importance of brain networks associated with reward related decision-making in daily life as morphological biomarkers for impulsivity in a normal healthy population. While our results in healthy volunteers may not directly extend to pathological conditions, they provide an insight into the mechanisms of impulsive behaviour in patients with abnormalities in prefrontal/frontal-striatal connections, such as in drug abuse, pathological gambling, ADHD and Parkinson's disease.

Fig. 1

Positive correlation between Barratt impulsivity scale (BIS) non-planning impulsivity score and delay discounting task (DDT) ln(k) (Pearson’s correlation coefficient r = 0.35, P < 0.05)

Fig. 2

Brain regions show the positive correlation of GM volume with BIS total score (upper figure) and BIS sub-scores (lower figure)

Fig. 3

Brain regions show the positive and negative correlation of GM volume with ln(k)