Neural activity in primate parietal area 7a related to spatial analysis of visual mazes
Neural activity in primate parietal area 7a related to spatial analysis of visual mazes
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DOI：
10.1093/cercor/bhg088
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发表时间：
2004-01-01
期刊：
影响因子：
3.7
通讯作者：
Georgopoulos, AP
中科院分区：
文献类型：
--
作者：
Crowe, DA;Chafee, MV;Georgopoulos, AP
对人类和猴子解决视觉迷宫的认知心理学研究提供了证据，表明对迷宫的秘密分析发生在眼球扫视之间的注视阶段，或者在没有眼球运动的情况下解决迷宫时。我们通过记录迷宫解题过程中7a区单个神经元的活动，研究了这一过程在顶后皮质的神经基础。猴子被要求通过单点注视来确定通过迷宫的关键路径是到达出口还是盲目尽头。我们发现，在这个过程中，7a区大约四分之一的神经元的活动在空间上被调整到迷宫路径方向。我们得到的证据表明，路径调整并不反映隐蔽的眼跳计划，因为在迷宫解题过程中激活的大多数神经元在延迟眼跳控制任务中并不活跃，并且在两个任务中都活跃的少数神经元在两种条件下都没有表现出一致的空间调整。我们还得到证据表明，迷宫解题过程中的路径调整并不是由于视觉感受野在迷宫解的行为背景之外的位置，因为感受野中心和优先路径方向在空间上不对齐。最后，当幼稚的动物看到相同的视觉迷宫刺激但没有解决它们时，7a区不存在调整到路径方向的神经元。这些数据支持这样的假设，即顶叶皮质的路径调整不是由于迷宫刺激的较低水平的视觉特征，而是与迷宫解决方案有关，因此反映了应用于复杂视觉刺激的认知过程。
Cognitive psychological studies of humans and monkeys solving visual mazes have provided evidence that a covert analysis of the maze takes place during periods of eye fixation interspersed between saccades, or when mazes are solved without eye movements. We investigated the neural basis of this process in posterior parietal cortex by recording the activity of single neurons in area 7a during maze solution. Monkeys were required to determine from a single point of fixation whether a critical path through the maze reached an exit or a blind ending. We found that during this process the activity of approximately one in four neurons in area 7a was spatially tuned to maze path direction. We obtained evidence that path tuning did not reflect a covert saccade plan insofar as the majority of neurons active during maze solution were not active on a delayed-saccade control task, and the minority that were active on both tasks did not exhibit congruent spatial tuning in the two conditions. We also obtained evidence that path tuning during maze solution was not due to the locations of visual receptive fields mapped outside the behavioral context of maze solution, in that receptive field centers and preferred path directions were not spatially aligned. Finally, neurons tuned to path direction were not present in area 7a when a naive animal viewed the same visual maze stimuli but did not solve them. These data support the hypothesis that path tuning in parietal cortex is not due to the lower level visual features of the maze stimulus, but rather is associated with maze solution, and as such, reflects a cognitive process applied to a complex visual stimulus.