A Novel Approach for Assessing Traumatic Brain Injury Induced Light Aversion in Mice

Abstract

Record ID: 204

Capstone Competition: 2nd Place Winner

Award(s): Excellence in Research Mentoring; Excellence in Research Communication

Category:  Sensing, Perception, & Sensoring Technology

Student Major: Neuroscience

Project Advisor: Nathan Evanson

Abstract: Up to 50% of traumatic brain injury (TBI) patients suffer from photalgia, abnormal light sensitivity, when exposed to bright light. The diffuse forces of a TBI commonly lead to tissue damage to vision-associated regions (e.g., the optic nerves and optic radiations), contributing to vison problems that arise after injury. Photalgia is also associated with cone dystrophy, the loss of retinal cones, and normal visual acuity relies on the proper function of cones at higher intensities of light to relay visual information to retinal ganglion cells (RGCs). It is, therefore, possible that if TBI leads to either photoreceptor or retinal ganglion cell dystrophy, we might be able to assess photalgia by testing visual acuity at varying light levels. We hypothesized that we could test for these cone/RGC-driven light sensitivities in the mouse via the optokinetic response (OKR). For, if this involuntary reaction to moving stimuli declines more severely after injury at higher light intensities, that could indicate photalgia. Male C57BL/6J mice experienced a closed-head, weight-drop TBI. OKR was observed two days before injury, then after injury on days 2, 3, 7, 9, 21, 23, 35, and 37. Mice were assessed under four light intensities: low (80 lux), room (400 lux), medium (1100 lux), and high (3200 lux). We expect that the optokinetic response will be triggered less when mice are exposed to high light intensities post-injury likely due to loss of cones. This study could be used as a new assay to understand light aversion in mice.