A team of HBP scientists in Madrid have published detailed 3D-maps of around 25,000 synapses in the Human Hippocampus. This part of the brain is known for its involvement in memory, learning and spatial orientation, and for being affected early in Alzheimers disease. Synapses are tiny contact points through which signals pass from one neuron to the other. The study provides the first detailed description of synaptic structure in this part of the brain.

The team of Prof. Javier DeFelipe at the Laboratorio Cajal de Circuitos Corticales (Centro de Tecnología Biomédica; UPM/CSIC, Madrid) and their collaborators led by Lidia Blázquez-Llorca used Electron Microscopy to image and reconstruct synapses from thin sections of donated brain tissue. The analysis revealed remarkable differences, with synapses more densely packed in some layers of the hippocampus than in others. The more precise picture could contribute to a better understanding of changes in disease and advance computational models of the brain. The ultrahigh-res datasets are made available through the Human Brain Project’s EBRAINS Knowledge Graph.

Connections between neurons in the human hippocampus in 3D. Excitatory synapses are shown in green and inhibitory synapses are shown in red. Image credit: Montero-Crespo et al. (CC BY 4.0)

Read more in the eLife digest article “Honing in on the hippocampus”

Contact:

Javier DeFelipe
Laboratorio Cajal de Circuitos Corticales
defelipe@cajal.csic.es

Original Publication:

Three-dimensional synaptic organization of the human hippocampal CA1 field
https://elifesciences.org/articles/57013

The datasets are published through the EBRAINS Knowledge Graph

EBRAINS
M Domínguez-ÁlvaroM Montero-CrespoL Alonso-NanclaresR RodriguezJ DeFelipe (2020)
Densities and 3D distributions of synapses using FIB/SEM imaging in the human Hippocampus (CA1) - Extension with additional subregions.
https://doi.org/10.25493/NRFB-7N5

EBRAINS

M Dominguez-AlvaroM Montero-CrespoL Alonso-NanclaresR RodriguezJ DeFelipe (2020)
Densities and 3D distributions of synapses using FIB/SEM imaging in the human hippocampus (CA1).
https://doi.org/10.25493/6HRE-F2Y

See also:

EBRAINS now a recommended data sharing service for Nature Scientific Data
Read more

HBP researchers in Spain identify neurons coordinating functional networks in the brain
Read more

Dendrite Activity May Boost Brain Processing Power
Read more

The hippocampus as never seen before
Read more