Faculty Mentor(s)

Dr. Andrew Gall, Psychology

Document Type


Event Date



Herpes simplex virus 1 (HSV-1) infection is a lifelong viral infection that affects approximately half of the human population (McQuillan et al., 2018), yet little is known about its neurological effects. There is correlational evidence that infection with HSV-1 can induce cognitive decline and increased anxiety behaviors (Harris & Harris, 2015; Steel & Eslick, 2015; Tarter, Simanek, Dowd, & Aiello, 2014). In addition, HSV-1 may be associated with disruptions to circadian rhythms because HSV-1 is associated with chronic fatigue syndrome (Bond & Dinan, 2006), the time of HSV-1 infection impacts the viral replication (Edgar, 2016), and HSV impacts CLOCK machinery (Zhuang et al., 2017). Despite all of these associations of HSV-1 mediated neurological changes, a direct cause-effect relationship has yet to be established. This gap is vital to address in order to understand how viral infections impact behavior.

In the current study, we examined causal relationships between HSV-1 infection and anxiety-like behaviors, and between HSV-1 infection and circadian rhythms. To achieve these aims, 20 BALB/c mice were infected with HSV-1 or vehicle via corneal scarification. Then, in various lighting conditions, infrared sensors tracked activity in order to non-invasively measure circadian rhythms. Next, potential differences in anxiety-levels were examined through behavioral testing (i.e., open field test, elevated zero maze, light-dark box). After behavioral testing, the animals were sacrificed and brain tissue was harvested.

We hypothesized that adult mice infected with HSV-1 would exhibit increased anxiety-like behaviors and disrupted circadian rhythms as compared to control mice. Preliminary data suggest that the groups did not significantly differ in total activity during the pre-inoculation phase. There were short-term (one week post inoculation) significant decreases in activity in the HSV-1 group; however, these differences disappeared by four weeks post inoculation.

These results will have important implications for understanding viral infections, specifically HSV-1, and how these infections impact anxiety-like behaviors and circadian rhythmicity.


This project was supported by the Hope College Neuroscience Program.