Transition of target-location signaling in activity of macaque lateral intraparietal neurons during delayed-response visual search
Transition of target-location signaling in activity of macaque lateral intraparietal neurons during delayed-response visual search
复制标题
延迟反应视觉搜索过程中猕猴侧顶内神经元活动中目标位置信号的转变
DOI：
10.1152/jn.00262.2014
复制
发表时间：
2015
影响因子：
2.5
通讯作者：
& Ogawa T
中科院分区：
文献类型：
--
作者：
Nishida S*;Tanaka T;& Ogawa T
外侧顶叶区 (LIP) 的神经元在视觉辨别和工作记忆维持过程中参与发出行为相关物体位置的信号。尽管之前的研究已经分别研究了这些认知过程，但它们在现实生活中通常表现为不可分割的连续过程。当执行任务持续需要两个认知过程时，人们对目标位置的神经表征如何改变知之甚少。我们通过记录执行延迟反应视觉搜索任务的猴子的 LIP 的单单元活动来研究这个问题，其中要求它们在刺激期间将目标与干扰物区分开来，记住在延迟期间呈现消失的目标的位置，并在反应期间向该位置进行扫视。根据目标位置是在感受野内部还是在感受野对面，使用响应调制来评估目标位置信号。尽管群体平均反应调制是一致的，并且在试验期间仅发生轻微变化，但由于 LIP 神经元子集的反应调制同时发生变化，反应调制的跨神经元模式在刺激抵消后 170 毫秒左右显示出显着且突然的变化，这表现出任务期间活动变化的异质模式。我们的研究结果表明，在持续需要视觉辨别和工作记忆来执行单一行为任务的条件下，刺激消失后，LIP 活动的跨神经元模式的目标位置信号会离散地变化。
Neurons in the lateral intraparietal area (LIP) are involved in signaling the location of behaviorally relevant objects during visual discrimination and working memory maintenance. Although previous studies have examined these cognitive processes separately, they often appear as inseparable sequential processes in real-life situations. Little is known about how the neural representation of the target location is altered when both cognitive processes are continuously required for executing a task. We investigated this issue by recording single-unit activity from LIP of monkeys performing a delayed-response visual search task in which they were required to discriminate the target from distractors in the stimulus period, remember the location at which the extinguished target had been presented in the delay period, and make a saccade to that location in the response period. Target-location signaling was assessed using response modulations contingent on whether the target location was inside or opposite the receptive field. Although the population-averaged response modulation was consistent and changed only slightly during a trial, the across-neuron pattern of response modulations showed a marked and abrupt change around 170 ms after stimulus offset due to concurrent changes in the response modulations of a subset of LIP neurons, which manifested heterogeneous patterns of activity changes during the task. Our findings suggest that target-location signaling by the across-neuron pattern of LIP activity discretely changes after the stimulus disappearance under conditions that continuously require visual discrimination and working memory to perform a single behavioral task.