Kubota M, Taniguchi I
Department of Neurophysiology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 101-0062, Japan.
J Neurophysiol. 1998 Aug;80(2):914-23. doi: 10.1152/jn.1998.80.2.914.
Whole cell recordings were made from zebra finch HVc neurons in slice preparations. Four distinct classes of neuron were found on the basis of their electrophysiological properties. The morphological characteristics of some of these neurons were also examined by intracellular injection of Lucifer yellow. Type I neurons (21 of 65 cells) had longer time-to-peak of an afterhyperpolarization following an action potential than the other classes. They exhibited both fast and time-dependent inward rectification and an initial high-frequency firing followed by a slower constant firing. Type I neurons had large somata and thick dendrites with many spines. The axons of some of the neurons in this class projected in the direction of area X of the parolfactory lobe. Type II neurons (30 of 65 cells) had a more negative resting membrane potential than the other classes. They exhibited fast inward rectification. Type II neurons could be divided into two subclasses by the absence (IIa; 22 cells) and the presence (IIb; 8 cells) of a low-threshold transient depolarization. Type IIa neurons had relatively small somata and thin, spiny dendrites. The axons of some of the neurons in this class projected in the direction of the robust nucleus of the archistriatum (RA). Type IIb neurons had relatively large somata and thick dendrites with many spines. Type III neurons (6 of 65 cells) had a shorter action-potential duration than the other classes. They exhibited prominent time-dependent inward rectification and a regular tonic firing with little or no accommodation. Type III neurons had beaded, aspiny dendrites. Type IV neurons (8 of 65 cells) had a longer action-potential duration, a much larger input resistance, and longer membrane time constant than the other classes. Type IV neurons had small somata and thin, short, sparsely spiny dendrites. The axons of some of the neurons in this class projected in the direction of the RA. These classes of neuron may play distinct roles in song production and representation in the HVc.
在脑片标本上对斑胸草雀HVC神经元进行全细胞记录。根据其电生理特性发现了四类不同的神经元。还通过细胞内注射荧光黄对其中一些神经元的形态特征进行了研究。I型神经元（65个细胞中的21个）在动作电位后的超极化后峰时间比其他类型的神经元长。它们表现出快速和时间依赖性内向整流，以及初始高频放电，随后是较慢的持续放电。I型神经元有大的胞体和有许多棘的粗树突。该类中的一些神经元轴突向副嗅叶X区方向投射。II型神经元（65个细胞中的30个）的静息膜电位比其他类型的神经元更负。它们表现出快速内向整流。II型神经元可根据是否存在低阈值瞬时去极化分为两个亚类（IIa；22个细胞）和存在低阈值瞬时去极化（IIb；8个细胞）。IIa型神经元有相对小的胞体和细的、有棘的树突。该类中的一些神经元轴突向古纹状体粗核（RA）方向投射。IIb型神经元有相对大的胞体和有许多棘的粗树突。III型神经元（65个细胞中的6个）的动作电位时程比其他类型的神经元短。它们表现出显著的时间依赖性内向整流和规则的紧张性放电，几乎没有或没有适应性。III型神经元有串珠状、无棘的树突。IV型神经元（65个细胞中的8个）的动作电位时程更长、输入电阻大得多、膜时间常数比其他类型的神经元长。IV型神经元有小的胞体和细的、短的、棘稀疏的树突。该类中的一些神经元轴突向RA方向投射。这些类型的神经元可能在HVC的鸣叫产生和表征中发挥不同的作用。
