Bullier J, McCourt M E, Henry G H
Department of Physiology, John Curtin School of Medical Research, Canberra City, A.C.T., Australia.
Exp Brain Res. 1988;70(1):90-8. doi: 10.1007/BF00271851.
The functional characteristics of the feedback connections from areas 18 and 19 to area 17 in the cat have been examined with electrophysiological techniques. The experiments involved single unit recording in laminae 2 and 3 of area 17 while stimulating electrically a small region of area 18 or 19. It was found that a precise retinotopic correspondence between the sites of recording and stimulation was necessary before neurons of area 17 could be activated by electrical stimulation in extrastriate areas. Latencies were long compared to those obtained after stimulation of the optic radiation. The mean latency for orthodromic drive from area 19 was 10.4 ms and 6.1 ms from area 18, suggesting that the conduction velocities in these pathways are of the order of 1 m/s. The jitter of the latency after repeated orthodromic stimulation was often shorter than 0.3 ms, indicating that a large number of the sampled neurons received a direct drive from area 18 or from area 19. The functional properties of neurons driven from area 19 were different from those of cells driven from area 18. Thus, most striate neurons orthodromically driven from area 19 were of the SH and S type whereas the cells activated by area 18 stimulation belonged to the C and B categories.
利用电生理技术研究了猫的18区和19区到17区的反馈连接的功能特性。实验包括在17区第2和第3层进行单单位记录，同时电刺激18区或19区的一个小区域。结果发现，在17区的神经元能够被纹外区域的电刺激激活之前，记录位点和刺激位点之间必须存在精确的视网膜拓扑对应关系。与刺激视辐射后获得的潜伏期相比，潜伏期较长。来自19区的顺行驱动的平均潜伏期为10.4毫秒，来自18区的为6.1毫秒，这表明这些通路中的传导速度约为1米/秒。重复顺行刺激后潜伏期的抖动通常短于0.3毫秒，这表明大量被采样的神经元接受了来自18区或19区的直接驱动。由19区驱动的神经元的功能特性与由18区驱动的细胞的功能特性不同。因此，大多数由19区顺行驱动的纹状神经元属于SH型和S型，而由18区刺激激活的细胞属于C类和B类。
