Increase of extracellular dopamine in primate prefrontal cortex during a working memory task. Masataka Watanabe, Tohru Kodama, Kazuo Hikosaka. Department of Psychology, Tokyo Metropolitan Institute for Neuroscience, Musashidai 2-6, Fuchu, Tokyo 183 JAPAN.
APStracts 4:195N, 1997.
ABSTRACT
The dopamine innervation of the prefrontal cortex is importantly involved in cognitive processes, such as tested in working memory tasks. However, there have been no studies directly investigating prefrontal dopamine levels in relation to cognitive processes. We measured frontal extracellular dopamine concentration using in vivo microdialysis in monkeys performing in a delayed alternation task as a typical working memory paradigm and in a sensory-guided control task. We observed a significant increase in dopamine level in the delayed alternation task, as compared both to the sensory-guided control task and the basal resting level. The increase was seen in the dorsolateral prefrontal, but not in the arcuate or orbitofrontal areas. The increase appeared to reflect the working memory component of the task, and was observed mainly in the lip areas of principal sulcus. While there was no significant difference in dopamine level between delayed alternation and sensory-guided control tasks in the premotor area, significant increases in dopamine concentration were observed during both tasks as compared to the basal resting level, indicating the importance of premotor dopamine for the motor response itself. 

Received 29 May 1997; accepted in final form 12 August 1997.
APS Manuscript Number J444-7.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 28 August 1997