146 | Hippocampal encoding of odor-spatial associative memory

Cognition, Behavior, and Memory

Author: Maria Sol Ramos | Email: m_sol_ramos@hotmail.com

Maria Sol Ramos , Antonia Marin-Burgin , Sebastian Romano , Julieta Campi , Noel Federman


The ability to store new information through a process of learning and retrieve it over time is an essential property of the brain. While navigating an environment, animals form an internal representation of space through the integration of diverse internal and external cues. This process depends on a specific brain region: the hippocampus. Information reaches the hippocampus via the dentate gyrus (DG) as the initial stage of the trysinaptic circuit and then propagates through CA3 and CA1. In our research, we are conducting experiments training mice in a virtual reality environment to perform a discrimination task. Under head-fixed conditions, water restricted mice learn to drink water or not, depending on distinct cues presented in a virtual corridor. Employing in-vivo electrophysiology recordings, we compared the response of DG and CA3 neurons in expert and naïve animals. Our aim is to decipher how these neurons encode and adjust their response to various task variables throughout the learning process. Furthermore, we want to understand the involvement of distinct DG neural populations in this task. We used c-fos GFP and Ascl1 mice to label engram neurons and adult-generated granule cells. Focusing in expert animals, we analyzed neural activation using confocal microscopy. Finally, we performed ex-vivo electrophysiology to record miniature postsynaptic currents. This allowed us to study potential differences in synaptic connectivity between engram and non-engram cells.