Neural Circuits and Systems Neuroscience
Author: Azul Silva | email: asilva@fmed.uba.ar
Azul Silva 1°, Pedro Bekinschtein 2°, Mariano Belluscio 1°
1° Grupo de Neurociencia de Sistemas, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO-Houssay), UBA-CONICET
2° Instituto de Neurociencia Cognitiva y Traslacional, Fundación INECO, CONICET
Place cells (PC) are hippocampal neurons with location-specific firing which generally change their firing when the context changes (remapping). As a population, PCs are thought to form a cognitive map of events, providing the spatial dimension of episodic memory. PC can also encode other aspects of an experience, such as object identity, reward valence, or time, suggesting that they can map non-spatial information. Several studies had shown PC remapping as a consequence of environmental changes. However, it is unclear if remapping is directly related to the expression of different episodic memories. This project aims to understand the role of PC activity in the retrieval of overlapping contextual memories. To this aim, we performed electrophysiological recordings in CA3 and CA1 (two hippocampal regions) while animals were executing a spontaneous object recognition task. This task allows discriminating if animals recognize a context as new or familiar based on object exploration. We recorded 326 CA3 PC and 318 CA1 PC. In both regions, we found different patterns of PC activity only when animals discriminate between contexts and similar patterns when animals recognize the context as familiar, regardless of changes in available contextual cues. These results suggest that PC are encoding animal internal representations of contexts instead of purely environmental differences.