Insular dopamine D2 receptors and novelty seeking personality in Parkinson's disease.

Novelty seeking is a temperament trait characterized by impulsiveness and exploratory behavior. Dopamine has been suggested to be the primary neurotransmitter modulator of novelty seeking, and in young healthy subjects, a correlation between increased novelty seeking and decreased insular cortical dopamine D2 receptor availability has been reported. The proposed link between dopamine deficiency and reduction in novelty seeking in Parkinson's disease is controversial. The present study examined whether a link between insular D2 receptor availability and novelty seeking can be replicated in Parkinson's disease patients. [11C]FLB 457 positron emission tomography imaging was carried out in 28 patients with Parkinson's disease, and the data were analyzed using voxel-based statistical analysis. The results demonstrated a negative correlation between the novelty seeking score and the dopamine D2 availability bilaterally in the insular cortex (corrected P=0.001; r=-0.74 [right hemisphere]; r=-0.66 [left hemisphere]). The results provide further support for a relationship between novelty seeking and insular D2 receptors. They indicate that the association is cross-cultural, independent of age, and unaffected by dopaminergic degeneration.