CONTRAST SENSITIVITY AND SPATIAL-FREQUENCY RESPONSE OF PRIMATE CORTICAL-NEURONS IN AND AROUND THE CYTOCHROME-OXIDASE BLOBS
CONTRAST SENSITIVITY AND SPATIAL-FREQUENCY RESPONSE OF PRIMATE CORTICAL-NEURONS IN AND AROUND THE CYTOCHROME-OXIDASE BLOBS
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DOI：
10.1016/0042-6989(94)00253-i
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发表时间：
1995-06-01
期刊：
影响因子：
1.8
通讯作者：
KAPLAN, E
中科院分区：
文献类型：
--
作者：
EDWARDS, DP;PURPURA, KP;KAPLAN, E
猕猴的纹状皮层含有大量细胞色素氧化酶（CO blobs）染色的斑块，这些斑块内和外的细胞通常被描述为属于两个不同的群体或流。为了更好地了解CO blobs的功能，我们测量了CO blobs内和周围单个神经元的对比灵敏度和空间频率响应，并使用新的定量方法评估了每个blobs的密度分布。我们发现，随着距离斑点中心的距离，CO密度逐渐下降；在一个典型的斑点中，CO密度在100 μ m范围内从75%下降到25%。记录仅限于皮质2/3层，这些层中的大多数神经元具有较差的对比灵敏度，与外侧束状核的细小细胞神经元相似，然而，在一小部分2/3层神经元中，我们发现了较高的对比灵敏度，与大细胞神经元相似，这些神经元被发现聚集在斑点中心附近。这一发现与（间接）微细胞输入均匀分布在2/3层和（间接）巨细胞输入集中在CO blobs一致。我们还测量了单个单元和多个单元活动的空间调谐曲线，与其他工作人员一致，我们发现靠近blobs中心的细胞的最佳空间频率较低（中值为2.8 c/deg），而在blobs区域的细胞的最佳空间频率分布在很宽的空间频率范围内。多单元活动的高截止空间频率随着距离斑点中心的距离而增加，我们发现空间带宽与距离斑点中心的距离没有相关性，所有测量的生理特性都随着距离CO斑点中心的距离而逐渐变化，这表明斑点细胞具有与非斑点细胞完全不同的视觉功能的观点可能需要重新评估。
The striate cortex of macaque monkeys contains an array of patches which stain heavily for the enzyme cytochrome oxidase (CO blobs), Cells inside and outside these blobs are often described as belonging to two distinct populations or streams, In order to better understand the function of the CO blobs, we measured the contrast sensitivity and spatial frequency response of single neurons in and around the CO blobs, Density profiles of each blob were assessed using a new quantitative method, and correlations of local CO density with the physiology were noted, We found that the CO density dropped off gradually with distance from blob centers: in a typical blob the CO density dropped from 75% to 25% over 100 mu m. Recordings were confined to cortical layers 2/3, Most neurons in these layers have poor contrast sensitivity, similar to that of the parvocellular neurons in the lateral geniculate nucleus, However, in a small proportion of layers 2/3 neurons we found higher contrast sensitivity, similar to that of the magnocellular neurons, These neurons were found to cluster near blob centers, This finding is consistent with (indirect) parvocellular input spread uniformly throughout layers 2/3, and (indirect) magnocellular input focused on CO blobs, We also measured spatial tuning curves for both single units and multiple unit activity, In agreement with other workers we found that the optimal spatial frequencies of cells near blob centers were low (median 2.8 c/deg), while the optimal frequencies of cells in the interblob regions were spread over a wide range of spatial frequencies, The high cut-off spatial frequency of multi-unit activity increased with distance from blob centers, We found no correlation between spatial bandwidth and distance from blob centers, All measured physiological properties varied guadually, with distance from CO blob centers, This suggests that the view of blob cells subserving visual functions which are entirely distinct from non-blob cells may have to be reevaluated.