Prieto J J, Peterson B A, Winer J A
Department of Molecular and Cell Biology, University of California, Berkeley 94720-2097.
J Comp Neurol. 1994 Jun 15;344(3):349-82. doi: 10.1002/cne.903440304.
This is a survey of the distribution, form, and proportion of neurons immunoreactive for gamma-aminobutyric acid (GABA) or glutamic acid decarboxylase (GAD) in cat primary auditory cortex (AI). The cells were studied in adult animals and were classified with respect to their somatic size, shape, and laminar location, and with regard to the origins and branching pattern of their dendrites. These attributes were used to relate each of the GAD-positive neuronal types to their counterparts in Golgi preparations. Each layer had a particular set of GABAergic cell types that is unique to it. There were 10 different GABAergic cell types in AI. Some were specific to one layer, such as the horizontal cells in layer I or the extraverted multipolar cells in layer II, while other types, such as the small and medium-sized multipolar cells, were found in every layer. The number and proportion of GABAergic cells were determined by using postembedding immunocytochemistry. The proportion of GABAergic neurons was 24.6%. This was slightly higher than the values reported elsewhere in the neocortex. The laminar differences in density and proportion of GABAergic and non-GABAergic neurons were also comparable (though somewhat higher) to those found in other cortical areas: thus, 94% of layer I cells were GABAergic, while the values in other layers ranged from 27% (layer V) to 16% (layer VI). Layer VI had the most heterogeneous population of GABAergic neurons. The proportion of these cells across different regions within AI was studied. Since some receptive field properties such as sharpness of tuning and aurality are distributed non-uniformly across AI, these might be reflected by regional differences across the cerebral cortex. There were significantly more GABAergic somata in layers III and IV in the central part of AI, along the dorsoventral axis, where physiological studies report that the neurons are tuned most sharply (Schreiner and Mendelson [1990] J. Neurophysiol. 64:1442-1459). Thus, there may be a structural basis for certain aspects of local inhibitory neuronal organization.
这是一项关于猫初级听觉皮层（AI）中对γ-氨基丁酸（GABA）或谷氨酸脱羧酶（GAD）免疫反应阳性的神经元的分布、形态和比例的研究。这些细胞取自成年动物，并根据其胞体大小、形状、层位位置以及树突的起源和分支模式进行分类。利用这些特征将每种GAD阳性神经元类型与其在高尔基染色标本中的对应类型进行关联。每一层都有一组特定的GABA能细胞类型，且这些类型是该层所特有的。AI中有10种不同的GABA能细胞类型。有些类型仅存在于某一层，如第I层的水平细胞或第II层的外向多极细胞，而其他类型，如中小型多极细胞，则存在于每一层。通过包埋后免疫细胞化学方法确定GABA能细胞的数量和比例。GABA能神经元的比例为24.6%。这略高于新皮层其他部位报道的值。GABA能和非GABA能神经元在密度和比例上的层间差异与其他皮层区域的情况相当（尽管略高）：因此，第I层94%的细胞是GABA能的，而其他层的值在27%（第V层）至16%（第VI层）之间。第VI层的GABA能神经元群体最为多样。研究了AI不同区域中这些细胞的比例。由于某些感受野特性，如调谐锐度和听觉性，在AI中分布不均匀，这些特性可能会通过大脑皮层的区域差异反映出来。在AI中央部分的第III层和第IV层，沿背腹轴方向，GABA能胞体显著更多，生理学研究表明该区域的神经元调谐最为尖锐（施赖纳和门德尔松[1990]《神经生理学杂志》64:1442 - 1459）。因此，局部抑制性神经元组织的某些方面可能存在结构基础。
