A Modified Beam-Walking Apparatus for Assessment of Anxiety in a Rodent Model of Blast Traumatic Brain Injury (P6.082)

Objective: Our study aimed to develop a novel beam-walking apparatus in addition to a novel anxiety index to simultaneously assess anxiety and motor functions in a rodent model of blast traumatic brain injury (bTBI). Background: The elevated plus maze (EPM) is commonly used to assess anxiety in rodents after brain injury. Beam-walking tasks are also routinely used to assess vestibulomotor function after brain injury in rodents. In this study, we evaluated the use of a novel modified beam-walking (MBW) apparatus containing a safe box as a surrogate indicator for anxiety using a novel model of bTBI. Methods: Wistar rats (N=39) were assessed before and at 3, 6, 24, 72, and 168h either post- bTBI (n=33) or no-injury (n=6) using both EPM and MBW apparatuses. A novel anxiety index was developed that incorporated the length of duration of peeking and full-body emergences out of the MBW safe box. Anxiety scores were compared with an anxiety index calculated from number and duration of entries into different sections of EPM. Results: Post- bTBI, rats had an increased anxiety index when measured using EPM. Similarly, they peeked or fully emerged less out of the safe box on MBW. It was found that this novel MBW anxiety index captured similar aspects of behavior when compared to the standard anxiety index obtained from EPM. Concurrently, peeking time, anxiety index, and motor function per MBW were found to be minimally multicollinear, indicating that the MBW apparatus succeeded at dissociating motor function and anxiety levels simultaneously. Over the course of 168h post-bTBI, rats gradually recovered on both EPM and MBW. Conclusions: In this study, we successfully developed a novel MBW apparatus that succeeded at capturing and dissociating two separate facets of rat behavior, motor function and anxiety, simultaneously. Disclosure: Dr. Sweis has nothing to disclose. Dr. Bachour has nothing to disclose. Dr. Safinia has nothing to disclose. Dr. Hevesi has nothing to disclose. Dr. Divani has nothing to disclose.