Vidyasagar T R, Mueller A
Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
Exp Brain Res. 1994;98(1):31-8. doi: 10.1007/BF00229106.
Responses of simple and complex cells in cat striate cortex were studied with moving sine-wave gratings before and during application of the GABAA receptor antagonist bicuculline methiodide. Both simple and complex cells exhibited a broadening of their spatial frequency tuning functions under bicuculline. This was especially evident at spatial frequencies lower than the ones the cell was responding to before the drug administration. The effects cannot be explained by response saturation and could be reversed by cessation of the iontophoresis. The results indicate that the band-pass response characteristics of the spatial frequency response functions of striate cells derive largely from intracortical inhibition. The findings have implications also for the orientation selectivity of cortical cells. Since many geniculate cells are tuned for stimulus orientation at higher spatial frequencies, suppression of the low-spatial-frequency component would remove some of the orientation non-specific response in striate cortical cells and contribute to their orientation selectivity.
在应用GABAA受体拮抗剂甲基荷包牡丹碱之前和期间，用移动的正弦波光栅研究了猫纹状皮层中简单细胞和复杂细胞的反应。在荷包牡丹碱作用下，简单细胞和复杂细胞的空间频率调谐功能均出现展宽。这在低于给药前细胞所响应的空间频率时尤为明显。这些效应不能用反应饱和来解释，并且可以通过停止离子电渗疗法而逆转。结果表明，纹状细胞空间频率反应函数的带通反应特性很大程度上源于皮质内抑制。这些发现对皮质细胞的方向选择性也有影响。由于许多膝状细胞在较高空间频率下对刺激方向进行调谐，低空间频率成分的抑制将消除纹状皮层细胞中一些方向非特异性反应，并有助于其方向选择性。
