Azouz R, Gray C M, Nowak L G, McCormick D A
Center for Neuroscience, University of California, Davis 95616, USA.
Cereb Cortex. 1997 Sep;7(6):534-45. doi: 10.1093/cercor/7.6.534.
Physiological and morphological properties of identified interneurons in the striate cortex of the cat were studied in vivo by intracellular recording and staining with biocytin. In conformity with in vitro studies, these non-pyramidal fast spiking cells have very brief action potentials associated with a high rate of fall, and a large hyperpolarizing afterpotential. These cells show high discharge rates, little or no spike frequency adaptation in response to depolarizing current injection, as well as a diverse range of firing patterns. Three of the cells were labeled and were found to be aspiny or sparsely spiny basket cells, with bitufted or radial dendritic arrangements, in layers II-IV. Their axonal arborizations were more dense near their somata and extended horizontally or vertically. Of 13 visually responsive cells tested, the receptive field properties of six cells and the orientation and direction preferences of eight cells were determined. Five of the successfully mapped cells had simple receptive fields while one had a complex receptive field type. The orientation and direction tuning properties of the overlapping set of eight cells showed a broad spectrum ranging from unselective to tightly tuned. The majority exhibited a clear preference for orientation and none of the cells were clearly direction selective. Quantitative analysis of the temporal properties of the spike trains during visual stimulation and spontaneous activity revealed that these cells do not exhibit any significant periodic activity, and fired at rates that were well below their maximum in response to depolarizing current pulses.
通过细胞内记录和生物胞素染色，在活体猫的纹状皮层中研究了已识别中间神经元的生理和形态特性。与体外研究一致，这些非锥体快速放电细胞具有非常短暂的动作电位，下降速率高，且有较大的超极化后电位。这些细胞放电频率高，对去极化电流注入的响应几乎没有或没有放电频率适应性，并且具有多种放电模式。其中三个细胞被标记，发现是无棘或稀疏有棘的篮状细胞，位于II-IV层，具有双簇状或放射状树突排列。它们的轴突分支在胞体附近更密集，并水平或垂直延伸。在测试的13个视觉反应细胞中，确定了6个细胞的感受野特性以及8个细胞的方向和方向偏好。成功绘制图谱的细胞中有5个具有简单感受野，而1个具有复杂感受野类型。8个细胞重叠组的方向和方向调谐特性显示出从非选择性到紧密调谐的广泛范围。大多数细胞对方向有明显偏好，并且没有细胞具有明显的方向选择性。对视觉刺激和自发活动期间的脉冲序列的时间特性进行定量分析表明，这些细胞没有表现出任何显著的周期性活动，并且在对去极化电流脉冲的响应中，其放电速率远低于其最大值。
