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

对大脑皮层局部神经回路的详细描述对于理解视觉皮质是如何工作的很重要。在这里，我们建立了一种刺激单个皮质神经元的方法，并分析来自神经元的输入如何影响附近神经元的放电活动。采用细胞旁记录和单玻璃电极电流刺激的方法，诱发和记录猫视皮质(17区)单个细胞(旁细胞)的棘波。同时，我们使用硅多点电极记录相邻细胞(邻近细胞)的活动。重复施加电流(0.5~3nA)(开启0.5s，关闭0.5s)，同时向眼睛呈现不同方位的空白屏幕或正弦栅格。仅皮质中的单个细胞就可以增加或减少附近细胞的放电频率。有效率多分布在/-0.2范围内。对于兴奋性连接，效应随前神经元(旁细胞)和后神经元(邻近细胞)的调谐相似性而线性增加(反应图)，而对于抑制性连接的有效性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.