VIP type neurons connect two brain regions involved in memory consolidation

Lisa Topolnik

Lisa Topolnik

Researchers have discovered a type of neuron that would coordinate the consolidation of memory

In an article published today in Nature Communications, researchers from Université Laval and Oxford University report having discovered a new type of neuron in the mouse brain. These neurons connect two structures associated with memory and may coordinate the consolidation of information about contextual or episodic memory.

The two structures in question are the hippocampus and the subiculum, explains the study lead, Lisa Topolnik, professor in the Department of biochemistry, microbiology and bioinformatics and researcher at the Centre de recherche du CHU de Québec – Université Laval. “The hippocampus encodes sensory information related to lived events and related context, including spatial landmarks. As for the subiculum, its functions relate to the recall of stored information. We knew that the two structures exchanged information, but we did not know how they managed to synchronize. ”

To explore the question, the researchers used a multiphoton microscope through which they studied neuronal activity in the hippocampus of awake mice. Their observations revealed the existence of a population of neurons (VIP type) that innervate the two structures. “The cell body of these neurons and a part of their axon are in the hippocampus, but their axon goes to the subiculum where it becomes very branched,” says Professor Topolnik.

This network allows the synchronized sending of information from the hippocampus to the subiculum. The data collected by the researchers indicate that the information transfer occurs mostly when the mouse is at rest and is reduced when the mouse starts moving. “Our hypothesis is that the mouse is taking advantage of break times to consolidate the information it has stored previously,” says Lisa Topolnik.

Are these neurons also present in the human brain? “Studies using transcriptomic analysis have revealed that the heterogeneity of VIP neurons is greater in humans than in mice,” says the researcher. It is therefore possible that the neurons we have discovered are also present in humans and that they are affected by certain diseases affecting memory, including Alzheimer’s. ”

The authors of the study published in Nature Communications are Ruggiero Francavilla, Vincent Villette, Xiao Luo, Einer Muñoz-Pino, Olivier Camiré and Lisa Topolnik, from the Research Center of CHU de Québec – Université Laval and the Department of Biochemistry, Microbiology and bioinformatics, Simon Chamberland, from the same department, and Kristina Wagner, Viktor Kis and Peter Somogyi, from Oxford University.

Source of text: Le Fil, Université Laval – Jean Hamann

Translation: CAN-ACN

Original research article

Francavilla R, Villette V, Luo X, Chamberland S, Muñoz-Pino E, Camiré O, Wagner K, Kis V, Somogyi P, Topolnik L. Connectivity and network state-dependent recruitment of long-range VIP-GABAergic neurons in the mouse hippocampus. Nat Commun. 2018 Nov 28;9(1):5043. doi: 10.1038/s41467-018-07162-5.