TOPOGRAPHIC ORGANIZATION OF THE ORIENTATION COLUMN SYSTEM IN THE STRIATE CORTEX OF THE TREE SHREW (TUPAIA-GLIS) .1. MICROELECTRODE RECORDING
TOPOGRAPHIC ORGANIZATION OF THE ORIENTATION COLUMN SYSTEM IN THE STRIATE CORTEX OF THE TREE SHREW (TUPAIA-GLIS) .1. MICROELECTRODE RECORDING
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DOI：
10.1002/cne.901920311
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发表时间：
1980-01-01
影响因子：
2.5
通讯作者：
NORTON, TT
中科院分区：
文献类型：
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作者：
HUMPHREY, AL;NORTON, TT
在树鼩纹状皮层的双眼部分进行微电极记录，以确定方向选择性细胞在区域 17 中的地形分布情况。在采样的细胞中，75% 被拉长的视觉刺激很好地激活，并且对刺激方向具有相当的选择性。在方向选择性细胞中，95% 的方向调整范围在 .+- 之间。 5.度。和.+-。 40度。从他们的最佳方向。具有相同或相似最佳方向的方向选择性细胞以柱状方式分布在皮层中，这是从几乎垂直于皮层表面的电极穿透确定的。平行于皮层表面的穿透揭示了最佳刺激方向的高度有序表示，通常以电极在纹状皮层上移动时最佳方向的顺序变化为特征。根据电极穿过皮层的移动方向，在这些穿透上的方向移动的速率和模式中观察到相对一致的差异。平行于 17-18 边界的穿透产生中等到高的方向变化率（平均斜率 = 434°/mm），变化通常通过 180° 的完整顺时针或逆时针循环进行。在取向转变方向发生重大逆转之前或更多。垂直于边界的渗透产生低至中等的坡度（平均坡度 = 239°/mm）。在这些穿透上，由于方向偏移方向的频繁反转，通常会遇到更有限的最佳方向范围（< 180°）。在这些穿透中观察到恒定最佳方向的扩展区域（100-200μm长）。在横穿纹状皮层的这些正交穿透上发现的不同方向变化模式表明，该物种的方向柱系统相对于 17-18 边界是各向异性组织的。在垂直于17-18边界的穿透上经常遇到的恒定最佳取向区域表明，各向异性是由近似垂直于17-18边界布置的等取向细长区域系统所促进的。
Microelectrode recordings were made in the binocular portion of the tree shrew striate cortex to determine how orientation selective cells are distributed topographically in area 17. Of the cells sampled, 75% were well activated by elongated visual stimuli and were quite selective for stimulus orientation. Of the orientation-selective cells, 95% had orientation tuning ranges between .+-. 5.degree. and .+-. 40.degree. from their optimal orientation. Orientation-selective cells with the same or similar optimal orientations were distributed in cortex in a columnar manner, as determined from electrode penetrations nearly normal to the cortical surface. Penetrations parallel to the cortical surface revealed a highly ordered representation of optimal stimulus orientation, generally characterized by sequential changes in optimal orientation with electrode movement across the striate cortex. Relatively consistent differences were observed in the rates and patterns of orientation shift on these penetrations depending on the direction of electrode movement across the cortex. Penetrations parallel to the 17-18 border yielded moderate-to-high rates of orientation change (mean slope = 434.degree./mm), with the changes generally progressing through a complete clockwise or counterclockwise cycle of 180.degree. or more before a major reversal in the direction of orientation shift was encountered. Penetrations perpendicular to the border yielded low-to-moderate slopes (mean slope = 239.degree./mm). On these penetrations a more limited range of optimal orientations (< 180.degree.) was usually encountered, due to frequent reversals in the direction of orientation shift. Extended regions (100-200 .mu.m long) of constant optimal orientation were observed in these penetrations. The different patterns of orientation change found on these orthogonal penetrations across the striate cortex indicate that the orientation column system in this species is anisotropically organized with respect to the 17-18 border. The regions of constant optimal orientation frequently encountered on penetrations perpendicular to the 17-18 border suggest that the anisotropy is subserved by a system of elongated zones of iso-orientation arranged approximately perpendicular to the 17-18 border.