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

Abstract

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 [ 11 C] raclopride PET in healthy subjects while performing the Montreal Card Sorting Task (MCST). We observed a striatal reduction in [ 11 C] 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.

Neuroimaging in Parkinson's Disease

“…In contrast, [ 11 C]raclopride has a lower affinity, and its binding is accordingly affected by changes in the availability of synaptic DA [45,46]. This can be used to advantage to estimate DA release in response to a variety of pharmacological [47,48], physical [49][50][51], or behavioral [52][53][54] C-labeled PHNO [64] may be used to estimate changes in synaptic DA. Because of its relative selectivity, PHNO may also be useful for visualizing dopamine D3 receptors.…”

The Neural Circuitry of Executive Functions in Healthy Subjects and Parkinson's Disease

“…Changes in [ 11 C]raclopride-binding potential (BP) provide a reasonable estimate of synaptic dopamine (DA) release in the striatum (Farde et al, 1986). This method has been widely used for investigation of the striatal dopaminergic transmission during various cognitive tasks (Goerendt et al, 2003;Ko et al, 2008a;Monchi et al, 2006a;Ouchi et al, 2002;Zald et al, 2004). To investigate the contribution of striatal DA during set shifting, Monchi et al (2006a) tested young healthy subjects using PET during retrieval with and without shift on a variant of the WCST, the MCST.…”

“…This method has been widely used for investigation of the striatal dopaminergic transmission during various cognitive tasks (Goerendt et al, 2003;Ko et al, 2008a;Monchi et al, 2006a;Ouchi et al, 2002;Zald et al, 2004). To investigate the contribution of striatal DA during set shifting, Monchi et al (2006a) tested young healthy subjects using PET during retrieval with and without shift on a variant of the WCST, the MCST. In this card sorting task, the subject had to match a test card to one of four reference cards by comparing the test card to a previously shown cue card held in memory to find the classification rule.…”

“…These findings suggest that striatal DA neurotransmission increases significantly during the performance of specific executive processes. Although [ 11 C]raclopride may offer important insights in striatal DA neurotransmission during executive functions (Ko et al, 2008a;Monchi et al, 2006a), its low affinity limits its application to extrastriatal regions such as the PFC .…”

News and views on in-vivo imaging of neurotransmission using PET and MRI

“…Striatal dopamine has also been found to be involved in the cognitive planning of a novel action and during the performance of executive processes. Using a Montreal card sorting task, a reduction by up to 13% in [ 11 C]raclopride binding potentials was found in subregions of the caudate and putamen 69 .…”