Visual, presaccadic, and cognitive activation of single neurons in monkey lateral intraparietal area
Visual, presaccadic, and cognitive activation of single neurons in monkey lateral intraparietal area
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DOI：
10.1152/jn.1996.76.5.2841
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发表时间：
1996-11-01
影响因子：
2.5
通讯作者：
Goldberg, ME
中科院分区：
文献类型：
--
作者：
Colby, CL;Duhamel, JR;Goldberg, ME
1. 后顶叶皮层包含有视觉反应的神经元，这些神经元与跳眼运动有关。我们记录了警觉的恒河猴的顶叶皮层亚区，侧顶叶内区（LIP）的单个神经元。为了更完整地描述LTP神经元反应的环境，我们使用了五个任务来测试感觉、运动和认知因素的影响。我们获得了91个神经元在多个任务中的定量数据。我们测量了中枢固定时的神经活动，以及与刺激发作和扫视发作的关系。LIP神经元对接受野中的静止刺激有视觉反应。这些视觉反应既发生在要求眼球向刺激方向运动的任务中，也发生在不允许眼球运动的任务中，这表明这种活动是感觉活动，而不是前视活动。3. 当猴子必须使用刺激提供的信息来指导其行为时，视觉反应会增强。与简单固定任务中的视觉反应幅度相比，在一个任务中，猴子对给定刺激的感觉反应幅度会增加，在这个任务中，猴子随后会向刺激发出信号的位置扫视。当猴子不看刺激时，视觉反应也会增强。这个结果表明，这种增强并不反映出眼跳准备，因为即使猴子不被允许做眼跳，反应也会增强。相反，增强反映了对感受野空间轨迹的注意分配。除了视觉反应外，许多LIP神经元还具有与眼跳相关的活动。大多数神经元的视觉反应强于与眼跳相关的激活。眼跳相关活动独立于视觉活动。在包括近期视觉刺激（记忆引导的扫视任务）和没有视觉刺激（习得性扫视任务）的试验中，也观察到类似的视前活动。我们观察到，在固定任务中，猴子可以预测到行为显著刺激的开始，活动增加。在刺激开始前，LIP神经元在注视任务中通常表现出低水平的背景放电。在外围注意和记忆引导的扫视任务中，当猴子等待与行为相关的刺激出现时，这种背景活动增加了。这几个任务的结果表明，LIP神经元在各种情况下都被激活，而不仅仅是参与感觉处理或运动计划。注意和预期对感觉反应的调节表明，认知因素在顶叶功能中起主要作用。
1. Posterior parietal cortex contains neurons that are visually responsive and active in relation to saccadic eye movements. We recorded from single neurons in a subregion of parietal cortex, the lateral intraparietal area (LIP), in alert rhesus monkeys. To characterize more completely the circumstances under which LTP neurons are responsive, we used five tasks designed to test the impact of sensory, motor, and cognitive factors. We obtained quantitative data in multiple tasks in 91 neurons. We measured neural activity during central fixation and in relation to stimulus onset and saccade onset.2. LIP neurons have visual responses to the onset of a stationary stimulus in the receptive field. These visual responses occurred both in tasks that require a subsequent eye movement toward the stimulus and in tasks in which eye movements are not permitted, indicating that this activity is sensory rather than presaccadic. 3. Visual responses were enhanced when the monkey had to use information provided by the stimulus to guide its behavior. The amplitude of the sensory response to a given stimulus was increased in a task in which the monkey would subsequently make a saccade to the location signaled by the stimulus, as compared with the amplitude of the visual response in a simple fixation task.4. The visual response was also enhanced when the monkey attended to the stimulus without looking at it. This result shows that enhancement does not reflect saccade preparation because the response is enhanced even when the monkey is not permitted to make a saccade. Instead, enhancement reflects the allocation of attention to the spatial locus of the receptive field.5. Many LIP neurons had saccade-related activity in addition to their visual responses. The visual response for most neurons was stronger than the saccade-related activation.6. Saccade-related activity was independent of visual activity. Similar presaccadic activity was observed in trials that included a recent visual stimulus (memory-guided saccade task) and in trials with no visual stimulus (learned saccade task).7. We observed increases in activity during fixation in tasks in which the monkey could anticipate the onset of a behaviorally significant stimulus. LIP neurons usually showed low levels of background firing in the fixation task during the period before stimulus onset. This background activity was increased in the peripheral attention and memory-guided saccade tasks during the period when the monkey was waiting for a behaviorally relevant stimulus to appear.8. The results from these several tasks indicate that LIP neurons are activated in a variety of circumstances and are not involved exclusively in sensory processing or motor planning. The modulation of sensory responses by attention and anticipation suggests that cognitive factors play a major role in parietal function.