Submission
| Title: | Out of Sight, Out of Mind: Using visual perception to probe subtle effects of mild traumatic brain injury on cortical physiology. |
| Presenter: | Elizabeth Frazier |
| Institution: | Frazier |
| Authors: | Elizabeth Frazier, Purdue University; Anne Sereno, Purdue University; Maria Dadarlat, Purdue University |
Abstract
| Background/Significance/Rationale: | Approximately 75% of traumatic brain injuries are mild (mTBI). mTBIs often cause protracted cognitive and behavioral symptoms without discernible cortical damage, posing diagnostic and monitoring challenges. Previous work has shown that mTBIs frequently lead to visual deficits and changes in cortical physiology but has failed to relate the two. Our objective is to use a murine mTBI model to study how post-mTBI changes in visualperception relate to physiological dysfunction and long-term deficits. |
| Methods: | We trained head-fixed C57BL/6 mice on a two-alternative forced choice (2AFC) task involving wheel-turn responses to indicate global motion perception in random dot kinematograms (RDK). We modulated task difficulty by varying RDK coherence. Once mice achieve proficiency, we will acutely record cortical activity using microelectrode arrays during 2AFC task performance. Finally, we validated parameters for inducing mTBI via a controlled cortical impact (CCI). We assessed injury severity through observations of skull cracking and cortical hematoma. Future steps will administer mTBI to trained mice and subsequently replicate the electrophysiology protocol. |
| Results/Findings: | A pilot group of mice (n = 3) demonstrated rapid learning in the 2AFC task, exceeding chance within five sessions. Mice achieved greater accuracy on higher global motion coherence trials but showed no significant reaction time differences. Selected CCI parameters (3 m/s speed, 0.5 mm depth, and 180 ms dwell time) produced the desired mild injury without anatomical damage. Further behavior testing will validate injury severity. |
| Conclusions/Discussion: | Preliminary psychometric data suggests mice can quickly and accurately learn to report their global motion perception. Further, upon integration of this task with electrophysiology, we can obtain concurrent evaluations of behavior and cortical physiology. |
| Translational/Human Health Impact: | Linking neural circuit dysfunction and visual acuity after mTBI allows estimation of human physiological damage via simple behavioral tasks. Success would provide an accessible, cost-effective tool to improve diagnosis and rehabilitation of patients with conventionally undetectable cortical injuries. |
