Ostos Sandra, Aparicio Guillermo, Fernaud-Espinosa Isabel, DeFelipe Javier, Muñoz Alberto
Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal (CSIC), Avenida Doctor Arce 37, 28002, Madrid, Spain.
Laboratorio Cajal de Circuitos Corticales (CTB), Universidad Politécnica de Madrid, Campus de Montegancedo, 28223, Pozuelo de Alarcón, Madrid, Spain.
Cereb Cortex. 2023 Mar 21;33(7):3882-3909. doi: 10.1093/cercor/bhac314.
Perisomatic GABAergic innervation in the cerebral cortex is carried out mostly by basket and chandelier cells, which differentially participate in the control of pyramidal cell action potential output and synchronization. These cells establish multiple synapses with the cell body (and proximal dendrites) and the axon initial segment (AIS) of pyramidal neurons, respectively. Using multiple immunofluorescence, confocal microscopy and 3D quantification techniques, we have estimated the number and density of GABAergic boutons on the cell body and AIS of pyramidal neurons located through cortical layers of the human and mouse neocortex. The results revealed, in both species, that there is clear variability across layers regarding the density and number of perisomatic GABAergic boutons. We found a positive linear correlation between the surface area of the soma, or the AIS, and the number of GABAergic terminals in apposition to these 2 neuronal domains. Furthermore, the density of perisomatic GABAergic boutons was higher in the human cortex than in the mouse. These results suggest a selectivity for the GABAergic innervation of the cell body and AIS that might be related to the different functional attributes of the microcircuits in which neurons from different layers are involved in both human and mouse.
大脑皮层中围绕胞体的GABA能神经支配主要由篮状细胞和吊灯细胞完成，它们分别以不同方式参与锥体细胞动作电位输出和同步的控制。这些细胞分别与锥体细胞的胞体（和近端树突）以及轴突起始段（AIS）建立多个突触。利用多重免疫荧光、共聚焦显微镜和三维定量技术，我们估算了位于人类和小鼠新皮层各皮质层的锥体细胞胞体和AIS上GABA能终扣的数量和密度。结果显示，在这两个物种中，围绕胞体的GABA能终扣的密度和数量在各层之间均存在明显差异。我们发现胞体或AIS的表面积与这两个神经元区域相邻的GABA能终末数量之间存在正线性相关。此外，人类皮层中围绕胞体的GABA能终扣密度高于小鼠。这些结果表明，对胞体和AIS的GABA能神经支配具有选择性，这可能与人类和小鼠中不同层神经元所参与的微回路的不同功能特性有关。
