RAPID COMMUNICATION Increase of Extracellular Dopamine in Primate Prefrontal Cortex During a Working Memory Task

Watanabe, Masataka, Tohru Kodama, and Kazuo Hikosaka. the animal needs to maintain a representation of the position Increase of extracellular dopamine in primate prefrontal cortex of the next key press in working memory during almost all during a working memory task. J. Neurophysiol. 78: 2795–2798, periods of task performance except for the time of the re1997. The dopamine innervation of the prefrontal cortex is involved sponse. Thus working memory is engaged during a much importantly in cognitive processes, such as tested in working memlonger period than in the delayed response task. This also ory tasks. However, there have been no studies directly investigatis reflected in prolonged memory-related neuronal activity ing prefrontal dopamine levels in relation to cognitive processes. during delayed alternation (Kubota and Niki 1971). We measured frontal extracellular dopamine concentration using