Phillips Anthony G, Ahn Soyon, Floresco Stan B
Department of Psychiatry and Brain Research Center, University of British Columbia, Vancouver, British Columbia, Canada, V6T 2A1.
J Neurosci. 2004 Jan 14;24(2):547-53. doi: 10.1523/JNEUROSCI.4653-03.2004.
Modulation of neural function in the prefrontal cortex (PFC) by dopamine (DA) is essential for higher cognitive processes related to attention, working memory, and planning of future behavior. The present study demonstrates that DA efflux in the PFC is increased in a phasic manner when a rat engages in search behavior for food reward on an eight arm radial maze guided by memory, independent of whether or not reward is obtained for making the correct choice. Furthermore, disruption of accurate recall of the correct pattern of arms induced by increasing the delay period from 30 min to 1 or 6 hr, is associated with attenuated DA efflux during the retrieval phase of the task. The observed increase in DA efflux in the absence of reward at a 30 min delay and the minimal increase during consumption of the same quantity of food during poor performance after an unexpected 6 hr delay, argue against a simple relationship between DA function in the PFC and reward processes. Instead, these data demonstrate a close functional relationship between the release of DA from terminals within the PFC and the retrieval of specific trial unique memories; furthermore, the magnitude of mesocortical DA efflux is predictive of the accuracy of this form of memory.
多巴胺（DA）对前额叶皮质（PFC）神经功能的调节对于与注意力、工作记忆及未来行为规划相关的高级认知过程至关重要。本研究表明，当大鼠在由记忆引导的八臂放射状迷宫中进行获取食物奖励的搜索行为时，PFC中的DA外流以阶段性方式增加，无论做出正确选择是否获得奖励。此外，将延迟期从30分钟增加到1或6小时所导致的正确臂模式准确回忆的破坏，与任务检索阶段DA外流减弱相关。在延迟30分钟且无奖励时观察到的DA外流增加，以及在意外延迟6小时后表现不佳期间消耗相同数量食物时DA外流的最小增加，均表明PFC中DA功能与奖励过程之间不存在简单关系。相反，这些数据表明PFC内终末释放的DA与特定试验独特记忆的检索之间存在密切的功能关系；此外，中皮质DA外流的幅度可预测这种记忆形式的准确性。
