LONG-RANGE HORIZONTAL CONNECTIONS AND THEIR ROLE IN CORTICAL REORGANIZATION REVEALED BY OPTICAL-RECORDING OF CAT PRIMARY VISUAL-CORTEX
LONG-RANGE HORIZONTAL CONNECTIONS AND THEIR ROLE IN CORTICAL REORGANIZATION REVEALED BY OPTICAL-RECORDING OF CAT PRIMARY VISUAL-CORTEX
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DOI：
10.1038/375780a0
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发表时间：
1995-06-29
期刊：
影响因子：
64.8
通讯作者：
GILBERT, CD
中科院分区：
文献类型：
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作者：
DAS, A;GILBERT, CD
皮层“点扩散”（PS）是由最小视觉刺激激活的皮层区域（1）。在这里，我们使用PS探索功能的作用，在正常猫初级视皮层（V1）的横向连接和参与地形重组的皮层视网膜病变。我们比较了与光学记录，这反映了尖峰和阈下活动，与细胞外电极，揭示尖峰活动单独测量的PS的分布。尖峰PS仅代表光学PS中所示的激活面积的5%，表明剩余的95%可能是由阈下激活产生的。阈下激活的模式的方向依赖性及其与方向列的密切匹配表明，从尖峰活动的轨迹辐射的长距离水平连接负责所观察到的激活。尖峰PS表现出各向异性和不均匀性，相关的方向列的模式，并表示在皮层表面上的视觉空间的表示失真。在重组皮层的尖峰PS扩大，近似的程度，在正常皮层中看到的光学PS，并建议重组介导的正常阈下激活阈上水平的揭露。重组皮层的方向图显示出与放置损伤前获得的方向图非常匹配，尽管地形图发生了很大的变化，这支持了内在水平连接负责重新映射的观点。
THE cortical 'point spread' (PS) is the area of cortex activated by a minimal visual stimulus(1). Here we use the PS to explore the functional role of lateral connectivity in normal cat primary visual cortex (V1) and its involvement in topographic reorganization of cortex following retinal lesions. We compared the distributions of PSs measured with optical recording, which reflects both spiking and subthreshold activity, with those measured with extracellular electrodes, which reveal spiking activity alone. The spiking PS represented only 5% of the area of activation shown in the optical PS, indicating that the remaining 95% was probably generated by subthreshold activation. The orientation dependence of the pattern of the subthreshold activation and its close match with orientation columns suggests that long-range horizontal connections radiating from the locus of spiking activity were responsible for the observed activation. The spike PS showed anisotropies and inhomogeneities that were related to the pattern of orientation columns and indicated distortions in the representation of visual space on the cortical surface. In the reorganized cortex the spike PS expanded, approximating the extent of the optical PS seen in normal cortex, and suggesting that reorganization was mediated by an unmasking of normally subthreshold activation to suprathreshold levels. The orientation map of the reorganized cortex showed a close match to that obtained before placing the lesion, despite the large shift in topography, supporting the idea that intrinsic horizontal connections were responsible for the remapping.