Sherk H
Department of Biological Structure, University of Washington, Seattle 98195.
J Neurosci. 1990 Aug;10(8):2780-90. doi: 10.1523/JNEUROSCI.10-08-02780.1990.
In the cat, areas 17 and 18 have 2 main cortical targets: area 19 and a large region of suprasylvian cortex, referred to here as the Clare-Bishop area (Hubel and Wiesel, 1969). The functional organization of the latter area is not well understood. It seems likely that its organization reflects, in part, the organization of its inputs from areas 17 and 18, and I therefore studied the functional organization of these inputs. Responses were recorded directly from afferents terminating in the Clare-Bishop area after silencing its cells by local injections of kainic acid. Afferents were precisely ordered according to preferred orientation in a fashion resembling the columnar organization of area 17. Preferred direction was also an important organizing parameter. Within sizable regions of cortex, directional preference changed gradually or not at all, while at these regions' boundaries, preferred direction reversed by 180 degrees. Except for a loose grouping according to eye dominance, afferents were not ordered according to other response properties. It is possible that the afferent array is also compartmentalized according to the area of origin of each afferent. Inputs from areas 17 and 18, for example, might end in separate territories in the Clare-Bishop area. However, physiological recording, as well as anatomical experiments, failed to show a clear segregation. This study provides the first direct demonstration that a cortico-cortical pathway can be organized according to particular response properties. While the existence of an organization according to preferred orientation was not surprising, the high degree of order was unexpected. It is also interesting that afferents were well ordered according to 1 parameter, directional preference, that is weakly organized, at best, in area 17.
在猫中，17区和18区有两个主要的皮质靶区：19区和一个大面积的上薛氏回皮质区域，此处称为克莱尔 - 毕晓普区（休伯尔和威塞尔，1969年）。后一个区域的功能组织尚未得到很好的理解。其组织似乎部分反映了来自17区和18区的输入组织，因此我研究了这些输入的功能组织。在通过局部注射 kainic 酸使克莱尔 - 毕晓普区的细胞沉默后，直接从终止于该区的传入纤维记录反应。传入纤维根据最佳方向精确排列，其方式类似于17区的柱状组织。最佳方向也是一个重要的组织参数。在相当大的皮质区域内，方向偏好逐渐变化或根本不变，而在这些区域的边界处，最佳方向反转180度。除了根据眼优势进行松散分组外，传入纤维没有根据其他反应特性进行排列。有可能传入纤维阵列也根据每个传入纤维的起源区域进行分隔。例如，来自17区和18区的输入可能终止于克莱尔 - 毕晓普区的不同区域。然而，生理学记录以及解剖学实验均未显示出明显的分隔。这项研究首次直接证明了皮质 - 皮质通路可以根据特定的反应特性进行组织。虽然根据最佳方向存在组织并不令人惊讶，但高度的有序性却出乎意料。同样有趣的是，传入纤维根据一个参数——方向偏好——排列良好，而方向偏好在17区充其量只是组织较弱。
