19 - The Preclinical Behavior and Modeling Core (PBMC) at Uniformed Services University of the Health Sciences (USUHS) introduces Mousewalker: Gait analysis in mice following traumatic brain injury.

Abstract Text: The Preclinical Behavior and Modeling Core (PBMC) offers facilities and expertise in traumatic brain injury (TBI) modeling and rodent behavioral testing to the Uniformed Services University of the Health Sciences community and beyond. Currently there are over 30 behavioral tests available for both mice and rats, and motor testing is a popular domain for evaluating functional deficits following TBI. Analysis of gait, the pattern of walking or sequence of foot movements during locomotion, has become increasingly included in behavioral protocols as it may reveal more subtle changes in motor coordination following insults. The mouse behavior division of the PBMC has recently acquired a Mousewalker device, allowing for detailed analysis of gait during voluntary locomotion in a narrow walkway. The apparatus has no moving parts and works on the concept of frustrated total internal reflection, resulting in the mouse’s footprints “glowing” on an acrylic surface. Computerized, automated analysis of recorded footprints results in output containing multiple measurements including walking speed, step distances, footprint clustering, multiple stance (time the foot is in contact with the ground) and swing (time the foot is not in contact with the ground) measures, body stability, gait symmetry, step frequency, stance width, leg-support index, duty factor and others. To determine if Mousewalker could detect gait deficits following a single mild TBI, data were collected in male mice one day following mild TBI inflicted by the Closed-Head Injury Model of Engineered Rotational Acceleration (CHIMERA; 0.6 J) device or sham procedures. Injured and sham-treated mice walked at similar speeds, and were equivalent on many measures including body stability, stepping frequency, stance and swing durations, duty factor, footprint clustering and gait symmetry. However, sham-treated mice had longer step distances than brain injured mice and were less likely to employ a three-legged stance support during walking. This data set demonstrates the comparability of Mousewalker to other more commonly-known gait analysis systems, as well as its utility in detecting subtle changes in gait following a single mild TBI.

Keywords: CHIMERA, blast, motor deficits, gait, behavior