Differences of horizontal collateralizations in commissure and association neurons

在细胞内记录2/3层锥体神经元对声刺激的反应。在轻度戊巴比妥麻醉下，在单耳和/或双耳条件下，将纯音、咔哒声、白色噪声和具有规定带宽的噪声施加到猫的外耳道。在许多神经元中，记录后注射生物胞素以追踪记录的神经元的轴突路线，以最佳或接近最佳的频率诱发兴奋性突触后电位（EPSP）。EPSP，往往与动作电位，其次是超极化偏转的膜电位（IPSP），这是更明显的第3层神经元比第2层神经元。在某些神经元中，如果声音强度增加，IPSP偏转增加，同时动作电位数目减少，显示非单调反应特性。在一些深层3神经元，双耳刺激与最佳或接近最佳的频率或噪声引起的尖峰比单耳刺激的任一耳朵，揭示了EI响应特性。然后，更强的IPSP与双耳刺激比单耳刺激，似乎减少双耳诱发spikes的数量。为了比较有IPSP和没有IPSP的神经元的轴突轨迹，一些记录，然后biocytin-injected neurons已经reconstructed.These结果和一些相关的数据已发表在摘要形式和/或全文。

Responses of layer 2/3 pyramidal neurons to sound stimuli were recorded intracellularly. Under a light Nembutal anaesthesia, pure tones, clicks, white noises, and noises with a defined band width were applied to cats' external meatus under monaural and/or binaural conditions. In many neurons, biocytin was injected after the recording to trace the courses of axons of the recorted neurons.Excitatory postsynaptic potentials (EPSPs) were induced with best or nearbest frequencies. EPSPs, often associated with action potentials, were followed by hyperpolarizing deflection of the membrane potential (IPSP), which was more conspicous in layer 3 neurons than in layer 2 neurons. In some neurons, if sound intensity was increased, IPSP deflection was increased together with the decreased number of action potentials, revealing the non-monotonic response properties. In some deep layer 3 neurons, binaural stimulation with the best or near-best frequencies or with noise induced less spikes than monaural stimulation of either ear, revealing the EI response properties. Then stronger IPSPs were associated with the binaural stimulation than monaural stimulaiton, and seem to reduce the number of binaurally-induced spikes.In order to compare axonal trajectories of the neurons with IPSP and without IPSP, some of the recorded and then biocytin-injected neurons have been reconstructed.These results and some related data have been published in abstract forms and/or in full papers.