Date of Award

12-2021

Document Type

Honors Thesis

Degree Name

Bachelor of Science

Department

Biological Science

Advisor/Committee Chair

Corey J. Frank

Major

Biology

Committee Member

Ewan C. McNay

Committee Member

Annalisa Scimemi

Abstract

Appropriate design and control of testing conditions during assessment of animal behavior is critical to maximize generalizability, replicability, and translational relevance. Some sensory stimuli are often controlled: for instance, during rodent behavioral testing, efforts are commonly made to reduce or eliminate olfactory and auditory distractions. However, less attention is paid to the ambient light level intensity (lux), which may vary even between rooms in the same facility. We sought to explore whether behavior is influenced by the standard illumination intensity in one of our behavioral testing rooms. To this end, we measured anxiety-like behaviors, exploration, and spatial memory performance in 7-month-old, male, Sprague-Dawley rats under conditions of either the standard bright light of the testing room (618 lux) or dim light (10 lux). During the open- field and novel object location tasks (OFT and NOL, respectively), rats in the bright light condition froze more often and spent more time frozen than rats in the dim condition. In addition, in the OFT with bright illumination, rats spent more time in the corners of the apparatus. No differences were detected in overall mobility or total time spent in the center of the OFT and in object preference or mobility in the NOL with varying levels of illumination. We conclude that in these rats, bright light increases freezing behaviors without altering overall mobility or spatial working memory performance. Our data confirm the importance of measuring, reporting, and controlling lux in experiments measuring rodent behavior.

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