Smith P H, Rhode W S
Department of Neurophysiology, University of Wisconsin, Madison 53706.
J Comp Neurol. 1987 Dec 15;266(3):360-75. doi: 10.1002/cne.902660305.
We report on the anatomical and physiological features of globular bushy cells in the posterior division of the anteroventral cochlear nucleus based on the characteristics of 20 cells from this population. Each of these cells was recorded from and characterized intracellularly and/or extracellularly, injected with horseradish peroxidase, and studied at the light and/or electron microscopic level. Intracellular records from the vicinity of the globular bushy cell body displayed large, fast synaptic potentials, and in some instances a larger presumed action potential both in silence and during short tone stimulation. Intraaxonal recordings displayed large action potentials in addition to small, fast potentials, which evidence indicates may be the decrementally conducted subthreshold synaptic potentials. Both recording situations indicated that these auditory nerve inputs need not be suprathreshold. Bushy cells with high characteristic frequencies (CFs greater than 3 kHz) typically showed primary-like-with-notch responses to short tones at CF or on-type L responses if the sustained level of discharge after the notch was not as robust. Low-CF bushy cells phase-locked after a well-timed onset spike. Light microscopic anatomy revealed a typically oval cell body giving rise to one or two primary dendrites that branched profusely and an axon that gave off no collaterals within the cochlear nucleus before entering the trapezoid body. Electron microscopic analysis showed a high concentration of large, round, vesicle-containing terminals on the cell body and primary dendrite while the population of terminals on the initial segment and sparsely covered distal dendrites was made up mostly of flat and pleomorphic vesicle-containing terminals.
我们基于来自该群体的20个细胞的特征，报告了前腹侧蜗神经核后部分球状浓密细胞的解剖学和生理学特征。对这些细胞中的每一个都进行了细胞内和/或细胞外记录、特征描述，注射辣根过氧化物酶，并在光镜和/或电镜水平进行研究。在球状浓密细胞体附近的细胞内记录显示出大的、快速的突触电位，在某些情况下，在静息和短音刺激期间还显示出更大的推测动作电位。轴突内记录除了小的、快速的电位外还显示出大的动作电位，有证据表明这些小的、快速的电位可能是递减传导的阈下突触电位。两种记录情况都表明这些听神经输入不一定是阈上的。具有高特征频率（CF大于3kHz）的浓密细胞通常对CF频率的短音表现出类似初级的带凹口反应，或者如果凹口后的持续放电水平不那么强烈，则表现为开型L反应。低CF浓密细胞在适时的起始尖峰后锁相。光镜解剖显示，典型的椭圆形细胞体发出一或两个大量分支的初级树突，以及一条在进入梯形体之前在蜗神经核内不发出侧支的轴突。电镜分析显示，细胞体和初级树突上有大量含大的圆形囊泡的终末高度集中，而起始段和稀疏覆盖的远端树突上的终末群体主要由含扁平囊泡和多形囊泡的终末组成。
