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 D-2 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 D-2 receptor availability and novelty seeking can be replicated in Parkinson's disease patients. [C-11]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 D-2 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 D-2 receptors. They indicate that the association is crosscultural, independent of age, and unaffected by dopaminergic degeneration. (C) 2004 Movement Disorder Society.