While the hippocampus is a crucial brain region for social memory, the memory of conspecific interactions, the precise mechanisms underlying the integration of social sensory cues with contextual information for the formation of episodic social memories are still unclear. This seminar examines the mechanisms of social sensory information processing by the hippocampus and presents a series of experiments using high-resolution imaging of populations of hippocampal neurons in awake mice exposed to social and non-social odors. These experiments show for the first time specific and robust social olfactory responses to individual conspecifics by neurons in a small subregion of the hippocampus called CA2. Statistical analysis shows that these responses are flexibly modulated during associative learning with social odor and reward, and optogenetic experiments show that CA2 activity is important for this learning. Finally, the experiments show that the CA2 neuronal activity space contains a higher-order structure that allows generalization along the categories of reward and social relevance, a feature that we find to be critically altered in a genetic mouse model of neuropsychiatric disease. This finding positions the genetic mouse model as well as the experimental paradigm as a promising avenue to investigate innovative therapeutic modalities targeting abnormalities in social cognition associated with neuropsychiatric disorders.
Further information: https://www.uni-bremen.de/mindtalks