Centre for Cognition and Neuroimaging, Brunel University, Uxbridge, UK.
J Neurophysiol. 2010 Oct;104(4):2169-77. doi: 10.1152/jn.00713.2009. Epub 2010 Aug 18.
Neurons that signal eye position are thought to make a vital contribution to distinguishing real world motion from retinal motion caused by eye movements, but relatively little is known about such neurons in the human brain. Here we present data from functional MRI experiments that are consistent with the existence of neurons sensitive to eye position in darkness in the human posterior parietal cortex. We used the enhanced sensitivity of multivoxel pattern analysis (MVPA) techniques, combined with a searchlight paradigm, to isolate brain regions sensitive to direction of gaze. During data acquisition, participants were cued to direct their gaze to the left or right for sustained periods as part of a block-design paradigm. Following the exclusion of saccade-related activity from the data, the multivariate analysis showed sensitivity to tonic eye position in two localized posterior parietal regions, namely the dorsal precuneus and, more weakly, the posterior aspect of the intraparietal sulcus. Sensitivity to eye position was also seen in anterior portions of the occipital cortex. The observed sensitivity of visual cortical neurons to eye position, even in the total absence of visual stimulation, is possibly a result of feedback from posterior parietal regions that receive eye position signals and explicitly encode direction of gaze.
据认为，传递眼球位置信号的神经元对于区分真实世界运动和由眼球运动引起的视网膜运动至关重要，但人类大脑中此类神经元的相关信息相对较少。在这里，我们呈现了功能磁共振成像实验的数据，这些数据与人类顶后皮质中存在对黑暗中眼球位置敏感的神经元的假设一致。我们使用多体素模式分析（MVPA）技术的增强灵敏度，结合搜索灯范式，来分离对注视方向敏感的脑区。在数据采集过程中，参与者被提示长时间将视线向左或向右，这是块设计范式的一部分。在将眼跳相关活动从数据中排除后，多元分析显示在两个局部顶后皮质区域（即背侧楔前叶和强度较弱的顶内沟后部）对眼位置具有敏感性。眼球位置的敏感性也可见于枕叶皮质的前部。即使在完全没有视觉刺激的情况下，视觉皮层神经元对眼球位置的敏感性可能是来自接收眼球位置信号并明确编码注视方向的顶后区域的反馈的结果。
