Visual, saccade-related, and cognitive activation of single neurons in monkey extrastriate area V3A
Visual, saccade-related, and cognitive activation of single neurons in monkey extrastriate area V3A
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DOI：
10.1152/jn.2000.84.2.677
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发表时间：
2000-08-01
影响因子：
2.5
通讯作者：
Colby, CL
中科院分区：
文献类型：
--
作者：
Nakamura, K;Colby, CL
V3A区是纹外视区，为顶叶皮质提供主要输入。为了识别V3A神经元携带的感觉、眼跳相关和认知信号，我们记录了清醒猴子在注视和记忆引导的眼跳任务中的单个单位。我们发现，V3A区对静止刺激的视觉反应受刺激的行为相关性的影响。视觉反应的幅度在记忆引导的眼跳任务和注视任务之间有所不同。在这种任务中，猴子必须使用刺激提供的信息来指导自己的行为。对于18%(29/163)的V3A神经元，在记忆引导的眼跳任务中的反应比在注视任务中显著增强。对于8%(13/163)的V3A神经元，在记忆引导的眼跳任务中，反应幅度受到显著抑制。我们还观察到在刺激开始之前，与任务相关的活动调节。在刺激前活动在不同任务间有显著差异的V3A神经元中(37/163)，大多数(89%；33/37)在记忆引导的眼跳任务中表现出更大的刺激前活动。在记忆引导的眼跳任务中，与任务相关的刺激前活动的增加并不总是与感觉反应的增加相匹配，这表明视觉反应和刺激前活动可以独立调节。与刺激前活动相比，83%(49/59)的V3A神经元在记忆期的活动受到抑制，这两个时期之间的活动存在显著差异(59/197)。对于一些神经元，在注视任务中，记忆期活动甚至下降到基线水平以下，这表明可能存在一种活跃的抑制机制。许多V3A神经元(75%，148/197)在眼跳时期也有活动。这种活动在扫视后立即表现得最为突出。即使在完全黑暗的情况下进行测试，也能观察到眼跳后的活动，这表明这种活动至少部分地反映了视网膜外信号，而不仅仅是对视觉重新传入的反应。这些结果表明，纹外区V3A的单个神经元携带着多种信号。此外，V3A的活动受到视网膜外因素的调节，包括注意力、预期、记忆和眼跳运动。
Area V3A is an extrastriate visual area that provides a major input to parietal cortex. To identify the sensory, saccade-related, and cognitive signals carried by V3A neurons, we recorded from single units in alert monkeys during performance of fixation and memory guided saccade tasks. We found that visual responses to stationary stimuli in area V3A were affected by the behavioral relevance of the stimulus. The amplitude of the visual response differed between the memory-guided saccade task, in which the monkey had to use the information provided by the stimulus to guide its behavior, and the fixation task. For 18% (29/163) of V3A neurons, the response was significantly enhanced in the memory-guided saccade task as compared with that in the fixation task. For 8% (13/163) of V3A neurons, the amplitude of response in the memory-guided saccade task was significantly suppressed. We also observed task-related modulation of activity prior to stimulus onset. Among the V3A neurons (37/163) that showed significant differences between tasks in prestimulus activity, the majority (89%; 33/37) showed greater prestimulus activity in the memory-guided saccade task. Task-related increases in prestimulus activity in the memory-guided saccade task were not always matched by increases in the sensory response, indicating that visual responses and prestimulus activity can be modulated independently. Activity in the memory period was suppressed compared with prestimulus activity for 83% (49/59) of the V3A neurons that showed a significant difference in activity (59/197) between these two epochs. For some neurons, memory-period activity dropped even below the baseline level in the fixation task, indicating that there may be an active suppression mechanism. Many V3A neurons (75%, 148/197) also had activity in the saccade epoch. This activity was most prominent immediately after the saccade. Postsaccadic activity was observed even when testing was carried out in total darkness, indicating that this activity reflects, at least in part, extraretinal signals and is not simply a response to visual reafference. These results indicate that several kinds of signals are carried by single neurons in extrastriate area V3A. Moreover, activity in V3A is subject to modulation by extraretinal factors, including attention, anticipation, memory, and saccadic eye movements.