Functions of the Cortical Amygdala in social behavior - Project Summary
Aggression is an evolutionarily conserved behavior that controls social hierarchies and protects valuable
resources like mates, food, and territory. In most cases, aggression is a necessary, adaptive component of
social behavior. In humans, however, some forms of aggression are considered pathological when they
threaten lives, increase the risk of psychiatric impairment in victims, and incur economic burdens on society.
Considerable evidence indicates that aggression is associated with aberrant facial perception in humans.
Physically aggressive individuals have a tendency to identify ambiguous faces as threatening or angry. This
suggests that these individuals have a perceptual bias which impairs the ability of the individual to interpret the
level of threat correctly. There is ample evidence in human and non-human primates that the amygdala plays a
key role in social perception. Studies with human and non-human primates examining the amygdala's role in
social perception have focused on the lateral and basolateral amygdala given their extensive connections with
the visual system and because they are a highly dependent on vision. Conversely, rodents are more reliant on
olfaction, and thus, we need a deeper understanding of amygdala interactions with olfactory structures during
social encounters. The posterior cortical amygdala (COAp) is one such region which receives input from
olfactory structures. Our preliminary data suggest that activation of ESR-1 cells in the COAp are necessary for
aggressive behavior to occur in males but not females. Furthermore, these cells show an increase in activity
during attack behavior in males. In addition to the expected input from the main olfactory bulb, we discovered
that this cell population also receives input from the ventral striatopallidal system, which is involved in
motivational processes. For the K99 phase of this proposal, I will test the hypothesis that the ventral
striatopallidal system affects the motivation to attack by modulating preparatory activity in the COAp. Over the
R00 phase, I will build a research program to test the hypothesis that the COAp mediates state-dependent
responses to social olfactory stimuli. In order to induce an “aggressive state” in mice we will use the social
instigation model. The results from this proposal will increase the field's understanding of how non-sensory
variables affect what are traditionally known as sensory regions. In addition, the proposed training will allow me
to develop a future research program geared towards identifying mechanisms underlying the effects of altered
behavioral states on perceptual processes.