Striatal dopamine release during performance of executive functions:: A [11C] raclopride PET study

To date, while the contribution of the striatum in executive processes is well documented, the role played by striatal dopamine during tasks requiring executive functions is still unknown. We used D2-dopamine receptor ligand [C-11] raclopride PET in healthy subjects while performing the Montreal Card Sorting Task (MCST). We observed a striatal reduction in [C-11] raclopride binding potential during planning of a set-shift when compared with matching according to an ongoing rule. These findings suggest that striatal dopamine neurotransmission increases significantly during the performance of specific executive processes confirming previous evidence of striatal activation during FMRI studies. The present observation may provide some insights on the origin of cognitive deficits underlying certain neurological disorders associated with dopamine dysfunction, such as Parkinson's disease. (c) 2006 Elsevier Inc. All rights reserved.