EVIDENCE FOR STRIATAL DOPAMINE RELEASE DURING A VIDEO GAME

Dopaminergic neurotransmission may be involved in learning, reinforcem ent of behaviour, attention, and sensorimotor integration(1,2). Bindin g of the radioligand C-11-labelled raclopride to dopamine D-2 receptor s is sensitive to levels of endogenous dopamine, which can be released by pharmacological challenge(3-8). Here we use C-11-labelled raclopri de and positron emission tomography scans to provide evidence that end ogenous dopamine is released in the human striatum during a goal-direc ted motor task, namely a video game. Binding of raclopride to dopamine receptors in the striatum was significantly reduced during the video game compared with baseline levels of binding, consistent with increas ed release and binding of dopamine to its receptors. The reduction in binding of raclopride in the striatum positively correlated with the p erformance level during the task and was greatest in the ventral stria tum. These results show, to our knowledge for the first time, behaviou ral conditions under which dopamine is released in humans, and illustr ate the ability of positron emission tomography to detect neurotransmi tter fluxes in vivo during manipulations of behaviour.