Inhibitory mechanisms influencing complex cell orientation selectivity and their modification at high resting discharge levels.

作者：Adam Murdin Sillito · 发表于：The Journal of Physiology · 年份：1979 · DOI：10.1113/jphysiol.1979.sp012723 · 被引用次数：311 · 研究领域：Neural dynamics and brain function、Neuroscience and Neuropharmacology Research、Visual perception and processing mechanisms

1. These experiments have investigated the contribution made by GABA-mediated inhibitory processes to the orientation tuning of complex cells in the cat's striate cortex. The GABA antagonist bicuculline has been ionophoretically applied to individual complex cells and the modifications produced in their orientation tuning documented. 2. In terms of the type of change produced in orientation tuning by the application of bicuculline, it seems that there are two categories of complex cells. 3. In one of these categories the orientation selectivity was eliminated during bicuculline application. The excitatory input to these cells would therefore appear to be non-orientation specific. Their orientation selectivity is presumably generated by a GABA-mediated inhibitory input. 4. In the other category of complex cells, although the orientation selectivity was decreased during bicuculline application, the cells retained a preference for a range of orientations that was generally centred around the original optimal orientation. It is suggested that for these cells the inhibitory input enhances the orientation tuning of an excitatory input that is already broadly orientation tuned. 5. Comparison of normal orientation tuning curves with those observed during the application of bicuculline provides a basis for estimating the orientation tuning of the GABA-mediated inhibitory input. In all cases, it is clear that at normal resting discharge levels, orientations either side of the optimal, ...