Although the hippocampus is well known to play a central role in declarative memory, its importance for motivated behaviors, including social aggression, remains relatively unexplored. I will report that hippocampal CA2 pyramidal neurons, previously implicated in social memory storage, promote social aggression through output to a lateral septal circuit that disinhibits neurons in the ventral medial hypothalamus, which triggers attack on a conspecific. In vivo fiber-photometry revealed enhanced CA2 activity during social encounters, with a selective increase in CA2 output to LS preceding attacks. The social hormone arginine-vasopressin enhanced social aggression by acting on arginine-vasopressin receptors 1b on CA2 presynaptic terminals in lateral septum that enhance excitatory synaptic transmission. In this manner, vasopressin release in lateral septum may serve as a gate driven by an animal’s internal state that enables a single brain region to either store declarative memory of a social encounter or promote motivated social aggression.
Friday, January 12 at 4:00pm to 5:00pm
Icahn School of Medicine at Mount Sinai, Hess Seminar Room B
One Gustave L. Levy Place New York, NY 10029-6574