3D ultrastructural study of synapses using FIB/SEM of deep layers from the human Entorhinal Cortex (v1)

We used Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) to perform a 3D analysis of the synapses in the neuropil in the deep layers of the medial Entorhinal Cortex (EC). 3 human brain autopsies cases have been used to achieve a total of 27 FIB/SEM valid images stacks. Specifically, we studied synaptic structural characteristics, which were fully reconstructed in 3D. We analyzed the synaptic density, 3D spatial distribution, and type (excitatory and inhibitory), as well as the shape and size of each synaptic junction. Moreover, their postsynaptic targets were determined. The present study has been performed in the same human samples already analyzed, using the same techniques, to describe the synaptic organization in the upper layers of the EC, which was previously released as “3D ultrastructural study of synapses using FIB/SEM of the human Entorhinal Cortex”. Present data on deep layers are intended to complete a detailed description of the synaptic organization of the human EC, to better understand the functional organization of the cortex in both health and disease.