Information transmission of local circuits in the primary visual cortex revealed by juxta-cellular single-cell stimulation

详细描述大脑皮层中的局部神经回路对于理解视觉皮层如何工作是很重要的。在这里，我们建立了一种方法来刺激单个皮层神经元，并分析来自神经元的输入如何影响附近神经元的尖峰活动。采用单玻璃电极刺激猫视皮层（17区）的单细胞（并列细胞），诱发并记录了放电。同时，我们使用硅多位点电极记录相邻细胞（邻近细胞）的活动。电流（0.5~ 3 nA）重复施加（0.5sec ON和0.5sec OFF），同时向眼睛呈现各种方向的空白屏幕或正弦光栅。皮层中的单个细胞可以单独增加或减少附近细胞的放电率。有效率大多分布在± 0.2范围内。对于兴奋性连接，功效随着前神经元（并列细胞）和后神经元（附近细胞）的调谐相似性而线性增加（响应图），而抑制性连接的功效不依赖于调谐相似性。

Detailed description of local neural circuits in the cerebral cortex is important for understanding how visual cortices work. Here, we established a method to stimulate single cortical neuron and analyze how inputs from the neuron affect spiking activities of nearby neurons. Using juxtacellular recording and current stimulation with single glass electrodes we evoked and recorded spikes from single cells (juxta-cells) in the cat visual cortex (area 17). Simultaneously we recorded activities of neighboring cells (nearby-cells) using silicon multi-site electrodes. Current (0.5～3nA) was repetitively applied (0.5 sec ON and 0.5 sec OFF) while blank screen or sinusoidal gratings of various orientations were presented to the eyes. Single cells in the cortex alone can increase or decrease firing rate of nearby cells. The efficacy rate mostly distributes in the range of +/-0.2. For excitatory connection, the efficacy increases linearly (response map) with tuning similarities of pre-neurons (juxta-cells) and post neurons (nearby cells), whereas the efficacy for inhibitory connection does not depend on the tuning similarities.