Net influx of plasma 6-[18F]fluoro-L-DOPA (FDOPA) to the ventral striatum correlates with prefrontal processing of affective stimuli

Abstract

Dopaminergic neurotransmission in the ventral and dorsal striatum interact with central processing of rewarding and reward-indicating stimuli, and may affect frontocortical-striatal-thalamic circuits regulating goal-directed behaviour. Thirteen healthy male volunteers were investigated with multimodal imaging, using the radioligand 6-[18F]fluoro-L-DOPA (FDOPA) for positron emission tomography (PET) measurements of dopamine synthesis capacity, and also functional magnetic resonance imaging (fMRI) in a cognitive activation paradigm. We calculated the correlation between FDOPA net blood-brain influx (Kinapp ml/g/min) in the ventral and associative dorsal striatum and BOLD signal changes elicited by standardized affectively positive, negative and neutral visual stimuli. The magnitude of Kinapp in the ventral striatum was positively correlated with BOLD signal increases in the left anterior cingulate cortex and right insular operculum elicited by positive vs. neutral stimuli, but not negative vs. neutral stimuli. In the dorsal striatum, the magnitude of Kinapp was positively correlated with processing of positive and negative stimuli in the left dorsolateral prefrontal cortex. These findings suggest that dopamine synthesis capacity in the ventral striatum correlates with the attentional processing of rewarding positive stimuli in the anterior cingulate cortex of healthy subjects. Dopaminergic neurotransmission in the associative dorsal striatum has been associated previously with habit learning. The observed correlation between dopamine synthesis capacity in the dorsal striatum and BOLD signal changes in the dorsolateral prefrontal cortex suggests dopaminergic modulation of processing of emotional stimuli in brain areas associated with motor planning and executive behaviour control. © The Authors (2006).