Parietal Cortical Neuronal Activity Is Selective for Express Saccades
Parietal Cortical Neuronal Activity Is Selective for Express Saccades
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DOI：
10.1523/jneurosci.2675-12.2013
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发表时间：
2013-01-09
影响因子：
5.3
通讯作者：
Zhang, Mingsha
中科院分区：
文献类型：
--
作者：
Chen, Mo;Liu, Yu;Zhang, Mingsha
眼跳运动是灵长类动物行为的核心，有助于将眼睛移动到感兴趣的视觉物体上。与常规眼跳不同，快速眼跳的反应时间非常短，这是目标导向行为中快速反应所必需的行为。先前的研究表明，在注视点偏移和扫视目标开始之间引入空白间隔（间隙）会导致快速扫视次数的增加，并且上丘在快速扫视的产生中起着至关重要的作用。一个长期存在的假设认为，快速眼跳主要是由皮层下回路介导的，绕过了纹状体外视觉皮层。另一种“后通路”假说提出了后顶叶皮层的参与。在本研究中，我们使用间隙扫视任务，研究了非人类灵长类动物的外侧顶内皮层（LIP）在快速扫视生成中的作用。我们发现大约一半记录的 LIP 神经元在间隙间隔期间受到调节。此外，一组在记忆引导扫视任务中具有持续活动的神经元在快速扫视期间的活动相对于常规扫视期间的活动有所增强。通过增加潜在目标位置来降低目标的确定性后，神经元活动在快速扫视期间保持在相似的水平，但在常规扫视期间显着减少，这与常规扫视中扫视反应时间的增加相关。我们的结果表明 LIP 区域直接参与快速模式下眼跳的产生。
Saccadic eye movements are central to primate behavior and serve to move the eyes to visual objects of interest. Express saccades, unlike regular saccades, occur with very short reaction times, a behavior necessary for speeded reactions in goal-directed behavior. Previous studies have shown that introduction of a blank interval (gap) between the fixation point offset and the saccadic target onset leads to an increase in the number of express saccades and that the superior colliculus plays a crucial role in the generation of express saccades. A longstanding hypothesis asserted that express saccades are mediated largely by a subcortical circuit, circumventing extrastriate visual cortex. An alternative "posterior pathway" hypothesis proposed the involvement of posterior parietal cortex. In the present study, using a gap saccade task, we investigated the role of nonhuman primate's lateral intraparietal cortex (LIP) in generation of express saccades. We show that roughly half of recorded LIP neurons were modulated during the gap interval. Moreover, a group of neurons with persistent activity in a memory-guided saccade task enhanced their activity during express saccades relative to that during regular saccades. After reducing the target's certainty by increasing the potential target locations, neuronal activity remained in the similar level during express saccades but markedly reduced during regular saccades that correlated with the increase of saccadic reaction time in the regular saccade. Our results suggest that area LIP is directly involved in generating saccades in express mode.