The role of feedback in shaping neural representations in cat visual cortex
The role of feedback in shaping neural representations in cat visual cortex
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DOI：
10.1073/pnas.242399199
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发表时间：
2002-12-24
影响因子：
11.1
通讯作者：
Payne, BR
中科院分区：
文献类型：
--
作者：
Galuske, RAW;Schmidt, KE;Payne, BR
在初级视皮层，具有相似反应偏好的神经元被分成不同的区域，形成刺激方向和运动方向的连续地图。这些特性被广泛认为是视觉系统上升和横向相互作用的结果。我们通过研究失活从视顶叶皮质下来的反馈信号对猫区18区这些反应特性和表征的出现的影响来检验这一观点。我们热失活了视顶叶皮质的主要运动处理区域，并使用光学和电生理方法来评估通过运动栅格和相干移动的随机分布的点场刺激在18区诱发的神经活动。反馈去激活降低了方向图和方向图中的信号强度，实际上取消了方向图的整体布局，而方向图的基本结构得到了保留，这些发现可以通过选择性地沉默高方向选择性神经元和选择性较低选择性神经元的偏好重定向来解释。我们的数据表明，从视顶叶皮质反馈的信号强烈地促进了早期视觉区域方向选择性的出现。因此，我们认为，当皮层较高的区域出现在较低的区域时，它们对神经元的基本特性有显著的影响。
In the primary visual cortex, neurons with similar response preferences are grouped into domains forming continuous maps of stimulus orientation and direction of movement. These properties are widely believed to result from the combination of ascending and lateral interactions in the visual system. We have tested this view by examining the influence of deactivating feedback signals descending from the visuoparietal cortex on the emergence of these response properties and representations in cat area 18. We thermally deactivated the dominant motion-processing region of the visuoparietal cortex and used optical and electrophysiological methods to assay neural activity evoked in area 18 by stimulation with moving gratings and fields of coherently moving randomly distributed dots. Feedback deactivation decreased signal strength in both orientation and direction maps and virtually abolished the global layout of direction maps, whereas the basic structure of the orientation maps was preserved, These findings could be accounted for by a selective silencing of highly direction-selective neurons and by the redirection of preferences of less selective neurons. Our data suggest that signals fed back from the visuoparietal cortex strongly contribute to the emergence of direction selectivity in early visual areas. Thus we propose that higher cortical areas have significant influence over fundamental neuronal properties as they emerge in lower areas.