Eysel U T, Shevelev I A
Department of Neurophysiology, Ruhr-Universität Bochum, Germany.
Neuroreport. 1994 Oct 27;5(16):2033-6. doi: 10.1097/00001756-199410270-00011.
A prominent feature of visual cortical neurones is orientation specificity. The underlying mechanisms and the possible contributions of intracortical inhibition are continuously the subject of intense debate. We analysed orientation tuning in relation to time after stimulus onset and the effects of blockade of GABAergic inhibition with microiontophoretically applied bicuculline in single cells in area 17. The majority of the cells had sharp and temporally stable orientation specificity; however, changes of receptive field structure, widening of orientation tuning and changes in preferred orientation were observed between 30 and 150 ms after stimulus onset when inhibition was blocked. This indicates that under normal conditions in most in most striate cortical cells intracortical inhibition sculptures receptive field structure and keeps orientation tuning narrow and constant in time.
视觉皮层神经元的一个显著特征是方向特异性。其潜在机制以及皮质内抑制可能发挥的作用一直是激烈争论的焦点。我们分析了与刺激开始后的时间相关的方向调谐，以及在第17区的单细胞中通过微量离子电泳施加荷包牡丹碱阻断GABA能抑制的效果。大多数细胞具有尖锐且时间上稳定的方向特异性；然而，在刺激开始后30至150毫秒之间，当抑制被阻断时，观察到感受野结构的变化、方向调谐的拓宽以及偏好方向的改变。这表明，在大多数纹状皮层细胞的正常条件下，皮质内抑制塑造了感受野结构，并使方向调谐在时间上保持狭窄且恒定。
