Discussion
Conspecifics constitute emotionally salient stimuli. Furthermore,
socio-sexual reward and aggressive- dominant aversion are largely
independent of homeostatic states such as hunger and thirst, rendering
them more amenable to experimental study than the physical stimuli of
food and water. In the present study of male mice, we demonstrate that:
(1) The intermediate-to-posterior BA contains a relatively high
number/density of glutamate neurons projecting to intermediate NAc
core/shell. (2) Approximately 15% of int-BA-NAc neurons are activated
by interaction with a (pro-)estrous female and 17% by interaction with
an aggressive-dominant male, whereas for post-BA-NAc neurons it is 8%
and 13%, respectively. (3) Using TRAPing, successive SR-SA or SA-SR
exposure identified that the majority of int-BA-NAc neurons activated by
SR are not activated by SA, and vice versa, i.e. the majority of
int-BA-NAc neurons are monovalent with respect to the social stimuli
investigated. (4) Using GCaMP6 fibre photometry of an int-BA-NAc
neuronal population, it could be demonstrated that they are engaged
during both distal and proximal interactions with SR. These findings
advance current understanding of how emotional stimulus processing by
BA-NAc glutamate neurons is organized in the mouse.