Neuronal Response Gain Enhancement prior to Microsaccades
Neuronal Response Gain Enhancement prior to Microsaccades
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DOI：
10.1016/j.cub.2015.06.022
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发表时间：
2015-08-17
期刊：
影响因子：
9.2
通讯作者：
Hafed, Ziad M.
中科院分区：
文献类型：
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作者：
Chen, Chih-Yang;Ignashchenkova, Alla;Hafed, Ziad M.
神经元反应增益增强是无需眼球运动的隐蔽视觉注意力分配的经典特征。然而，在注视期间，微眼跳会持续发生。因为这些微小的眼球运动在被触发之前就已经出现了运动准备信号，所以即使没有注意提示，这些信号的必然结果也可能会导致增强。在六只不同的猕猴和两个先前与隐蔽视觉注意有关的不同大脑区域（上丘和额眼区域）中，我们显示出对微跳视之前立即出现的外周刺激的神经元反应增益增强。这种增强既发生在行为无关的周围刺激的简单注视期间，也发生在刺激与随后的隐蔽视觉注意分配相关时。此外，这种增强发生在纯视觉神经元和视觉运动神经元中，并且被微扫视后立即出现的刺激的抑制所取代。我们的结果表明，微眼跳的发生和外周选择性处理之间可能存在必然的联系，尽管微眼跳可能比外周刺激的偏心率小几个数量级。由于微扫视在注视过程中以重复的方式发生，并且由于这些眼球运动每次发生时都会重置神经生理节律，因此我们的结果强调了一种可能的机制，通过该机制，动眼事件可以帮助对视觉环境进行定期采样，以利于感知，即使在凝视被阻止明显转移的情况下也是如此。这种周期性采样的功能性后果之一可能是外围隐蔽视觉注意力的节律波动的放大。
Neuronal response gain enhancement is a classic signature of the allocation of covert visual attention without eye movements. However, microsaccades continuously occur during gaze fixation. Because these tiny eye movements are preceded by motor preparatory signals well before they are triggered, it may be the case that a corollary of such signals may cause enhancement, even without attentional cueing. In six different macaque monkeys and two different brain areas previously implicated in covert visual attention (superior colliculus and frontal eye fields), we show neuronal response gain enhancement for peripheral stimuli appearing immediately before microsaccades. This enhancement occurs both during simple fixation with behaviorally irrelevant peripheral stimuli and when the stimuli are relevant for the subsequent allocation of covert visual attention. Moreover, this enhancement occurs in both purely visual neurons and visual-motor neurons, and it is replaced by suppression for stimuli appearing immediately after microsaccades. Our results suggest that there may be an obligatory link between microsaccade occurrence and peripheral selective processing, even though microsaccades can be orders of magnitude smaller than the eccentricities of peripheral stimuli. Because microsaccades occur in a repetitive manner during fixation, and because these eye movements reset neurophysiological rhythms every time they occur, our results highlight a possible mechanism through which oculomotor events may aid periodic sampling of the visual environment for the benefit of perception, even when gaze is prevented from overtly shifting. One functional consequence of such periodic sampling could be the magnification of rhythmic fluctuations of peripheral covert visual attention.