Peterhans E, Bishop P O, Camarda R M
Exp Brain Res. 1985;57(3):512-22. doi: 10.1007/BF00237838.
Quantitative estimates of the direction selectivities of 118 simple cells in response to moving light bars were expressed as a percentage calculated from the ratio of the response peaks: (preferred minus nonpreferred)/preferred. Virtually all simple cells were direction selective to some degree (mean direction selectivity 73.6%). Static-field plots to a stationary flashing bar were prepared from 74 of the 118 cells. Particular attention was given to the 42 cells with only two subregions in their static-field plot, one subregion responding at light on and the other at light off. It was concluded that interactive effects between subregions, whether synergistic or antagonistic, have little if any influence on the direction selective mechanism when the stimulus is a narrow light bar. Eighty two of the 118 cells were also tested with moving light and dark edges and of these 53 had response profiles with only two response peaks, one to the light edge and the other to the dark edge. Forty one of the 53 cells were each not only direction selective for both a light edge and a dark edge but also had a preferred direction for both edges that was the same as that for a light bar. Only two cells had preferred directions for both light and dark edges that were opposite to the direction preferred by the light bar. With one possible exception, every cell with two response static-field plot showed a one-to-one correspondence between the ordinal sequence of the response peaks and the ordinal sequence of the subregions. Depending upon the polarity of the moving edge and the ordinal sequence of the subregions, the mean level of the direction selectivity to a moving edge was significantly below that to a narrow moving light bar. This reduction in the degree of the direction selectivity appears to be due to an interaction between the subregions leading to a reduction in the amplitude of the response in the preferred direction rather than a suppression of the direction selective mechanism that operates in the nonpreferred direction. Moving edges cause a weak interactive effect between the subregions that seems always to reduce the degree of the direction selectivity, never increasing it.
对118个简单细胞对移动光条的方向选择性进行定量估计，以响应峰值之比计算的百分比表示：(偏好方向减去非偏好方向)/偏好方向。几乎所有简单细胞在某种程度上都具有方向选择性（平均方向选择性为73.6%）。从118个细胞中的74个细胞制备了对静止闪烁光条的静态场图。特别关注了静态场图中只有两个子区域的42个细胞，一个子区域在光照时响应，另一个子区域在光灭时响应。得出的结论是，当刺激是窄光条时，子区域之间的相互作用，无论是协同的还是拮抗的，对方向选择机制几乎没有影响。118个细胞中的82个也用移动的亮暗边缘进行了测试，其中53个细胞的响应曲线只有两个响应峰值，一个对应亮边缘，另一个对应暗边缘。53个细胞中的41个不仅对亮边缘和暗边缘都具有方向选择性，而且对两个边缘的偏好方向都与对光条的偏好方向相同。只有两个细胞对亮边缘和暗边缘的偏好方向与光条偏好的方向相反。除了一个可能的例外，每个具有两个响应静态场图的细胞在响应峰值的顺序序列和子区域的顺序序列之间都表现出一一对应关系。根据移动边缘的极性和子区域的顺序序列，对移动边缘的方向选择性平均水平明显低于对窄移动光条的方向选择性平均水平。方向选择性程度的这种降低似乎是由于子区域之间的相互作用导致偏好方向上响应幅度的降低，而不是对非偏好方向上起作用的方向选择机制的抑制。移动边缘会导致子区域之间产生微弱的相互作用，这种相互作用似乎总是会降低方向选择性程度，而不会增加它。
