Undergraduate Honors Theses

Thesis Defended

Spring 2019

Document Type


Type of Thesis

Departmental Honors


Psychology & Neuroscience

First Advisor

Zoe Donaldson

Second Advisor

Heidi Day

Third Advisor

Alison Vigers


Social interactions are vital to human health, in part, due to social buffering. Social buffering is the phenomenon by which fear and anxiety are reduced by the presence of an affiliative conspecific. While studies have demonstrated the behavioral effects of social buffering, there is less known about how these effects are mediated within the brain. There is evidence that the infralimbic cortex (IL) cortex is important in processing social information, and previous work in the Donaldson lab has demonstrated that optogenetic reactivation of cells previously active during novel social interaction (socially-labeled cells) in the IL was sufficient to decrease fear and anxiety behaviors in mice. To confirm activation of the IL in response to a conspecific’s presence, this study examined c-Fos expression in the IL in response to novel or familiar social interaction. Analysis of tissue revealed significant differences in cell counts between the social conditions and the controls, but not between the novel and familiar social conditions. In addition to the IL, the lateral septum (LS) has been implicated in social cognition and anxiety. Thus, this study also examined the behavioral effects of optogenetically activating socially-labeled cells in the LS of mice. Little behavioral differences were exhibited on the real-time place preference task, elevated plus maze, open field test, and social interaction task which may suggest that the LS is not involved in social buffering. However, due to limited cell labeling, further research is warranted. Together, this study further elucidates important neuroanatomical regions involved in social processing and social buffering.