Coding of Social Novelty in the Hippocampal Cornu Ammonis 2 Region (CA2) and Its Disruption and Rescue in a Mouse Model of Schizophrenia
The hippocampus is a brain structure known for its role in declarative memory- our ability to consciously recall facts and events. The hippocampus is a highly heterogeneous brain structure, and the small subregion CA2 has been shown to be necessary for the formation of social memories, the ability of an animal to recognize previously encountered conspecifics. Changes in excitatory/inhibitory balance have been observed in CA2 in humans with schizophrenia and in mouse models of schizophrenia, suggesting that these alterations may lead to some of the social dysfunction seen in schizophrenia. Although the hippocampal CA2 region has been implicated in social memory and neuropsychiatric disorders, little is known about how CA2 neural activity may encode social interactions and how this coding may be altered in disease. To see if and how CA2 codes for social interactions, I recorded extracellularly from CA2 pyramidal neurons as mice engage in a three-chamber social interaction task where the mice interact with the following task dimensions: space, novel objects, familiar social stimuli, novel social stimuli, and the passage of time.