Abstract
2010
Objectives Impulsivity is a multifactorial personality trait, described as the tendency to respond to stimuli recklessly without forethought, planning, or regard for the consequences. Previous findings suggest a link between dopamine (DA) neurotransmission and impulsivity, with disruptions in both being associated with psychiatric disorders and drug dependence. Recent studies have reported correlations between various measurements of impulsivity and DA D2 receptor availability, measured as binding potential (BPND) in mesolimbic and cortical brain regions. The goal of this study was to examine associations between subscale scores on the Impulsiveness-Venturesomeness-Empathy questionnaire in 15 non-smoking healthy males and DA D2 receptor availability, in subcortical brain regions using [18F]fallypride and PET.
Methods Image processing and volume-of-interest analyses were performed using a reference-region model, FSL FIRST and PMOD 3.1. Separate 2-group MANOVAs (Hotelling T-Square) were performed, comparing low (L) and high (H) scorers on the impulsiveness (7L, 8H), venturesomeness (6L, 9H) and empathy (6L, 9H) subscales. DA D2 receptor availability in the globus pallidus (GP), putamen (PU), caudate nucleus (CN), thalamus (TH), ventral tegmental area (VTA) and nucleus accumbens (NA) were the dependent variables; SPSS 20 was used.
Results There were no significant differences between the groups in age, education, injected dose or specific activities. We found a significant effect of group (L vs H groups) with venturesomeness but not with the other subscale scores. Scores on the venturesomeness subscale were correlated positively with DA D2 receptor availability in the GP and TH (p’s≤ 0.01), PU, VTA and NA (p’s ≤ 0.05). There were no other significant correlations.
Conclusions Our findings suggest that greater subcortical DA D2 receptor availability is associated with thrill-seeking and venturesomeness (a facet of impulsivity).
Research Support R03AA20190-01 NIAA
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