EXPERIENCE-DEPENDENT NETWORK EXCITABILITY IN DORSAL CA2 DURING TERRITORIAL AGGRESSION

Territorial behaviour is the process by which animals create and defend familiar space, often through aggression towards intruding members of the same species. These processes are thought to involve brain circuitry that incorporates social experience and memory, in which the hippocampus is thought to play a key role. The current study investigated the changes in neuronal activity in the dorsal CA2 (dCA2) hippocampal region during the development of territorial aggression using the resident-intruder model.
In vivo calcium imaging was performed in dCA2, with multiple recording sessions across 41 days. Mice were housed under resident conditions for several weeks to establish territorial familiarity. After intruder exposure, aggressive behavior was found to rise progressively in the following days in both experimental paradigms. The progression in aggression was found to correlate with the rise in the number of active dCA2 neurons, signifying the development of long-term excitability. The rise in the number of active neurons was found to persist across sessions, and it correlated with the onset of aggressive behavior. We hypothesize that dCA2 plasticity might underlie the development of representations of aggression.
These studies suggest that dCA2 is a locus of experience-dependent network plasticity related to territorial aggression.