RT Journal Article T1 Quantitative analysis of the GABAergic innervation of the soma and axon initial segment of pyramidal cells in the human and mouse neocortex A1 Ostos, Sandra A1 Aparicio, Guillermo A1 Fernaud Espinosa, Isabel A1 DeFelipe, Javier A1 Muñoz Céspedes, Alberto AB 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. PB Oxford University Press SN 1047-3211 YR 2022 FD 2022-09-05 LK https://hdl.handle.net/20.500.14352/125041 UL https://hdl.handle.net/20.500.14352/125041 LA eng NO Ostos, S., Aparicio, G., Fernaud-Espinosa, I., DeFelipe, J., & Muñoz, A. (2023). Quantitative analysis of the GABAergic innervation of the soma and axon initial segment of pyramidal cells in the human and mouse neocortex. Cerebral cortex (New York, N.Y. : 1991), 33(7), 3882-3909. https://doi.org/10.1093/CERCOR/BHAC314 NO This work was supported by the following entities: grants SAF 2010-18218 and PID2021-127924NB-I00 funded by MCIN/AEI/10.13039/501100011033; Centro de Investigación en Red sobre Enfermedades Neurodegenerativas (CIBERNED, CB06/05/0066); and CSIC Interdisciplinary Thematic Platform (PTI) Cajal Blue Brain (PTI-BLUEBRAIN; Spain). NO Ministerio de Ciencia e Innovación (España) NO Centro de Investigación en Red sobre Enfermedades Neurodegenerativas NO Consejo Superior de Investigaciones Científicas (España) DS Docta Complutense RD 19 oct 2025