Cortical synapses of the world's smallest mammal: An FIB/SEM study in the Etruscan shrew

The main aim of the present study was to determine if synapses from the exceptionally small brain of the Etruscan shrew show any peculiarities compared to the much larger human brain. We analyzed the cortical synaptic density and a variety of structural characteristics of 7,239 3D reconstructed syna...

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Detalles Bibliográficos
Autores: Alonso-Nanclares, Lidia, Rodríguez Sánchez, José Rodrigo, Merchán-Pérez, Ángel, González-Soriano, Juncal, Plaza-Alonso, Sergio, Cano-Astorga, Nicolás, Naumann, Robert K., Brecht, Michael, DeFelipe, Javier
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2023
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/343098
Acceso en línea:http://hdl.handle.net/10261/343098
Access Level:acceso abierto
Palabra clave:FIB-SEM
brain
cerebral cortex
Electron microscopy
synaptic junction
ultrastructure.
Descripción
Sumario:The main aim of the present study was to determine if synapses from the exceptionally small brain of the Etruscan shrew show any peculiarities compared to the much larger human brain. We analyzed the cortical synaptic density and a variety of structural characteristics of 7,239 3D reconstructed synapses, using using Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM). We found that some of the general synaptic characteristics are remarkably similar to those found in the human cerebral cortex. However, the cortical volume of the human brain is about 50,000 times larger than the cortical volume of the Etruscan shrew, while the total number of cortical synapses in human is only 20,000 times the number of synapses in the shrew, and synaptic junctions are 35% smaller in the Etruscan shrew. Thus, the differences in the number and size of synapses cannot be attributed to a brain size scaling effect but rather to adaptations of synaptic circuits to particular functions.