Longitudinal Assessment of Sensorimotor Function after Controlled Cortical Impact in Mice: Comparison of Beamwalk,...

Traumatic brain injury (TBI) patients are reported to experience long-term sensorimotor dysfunction, with gait deficits evident up to 2 years after the initial brain trauma. Experimental TBI including rodent models of penetrating ballistic-like brain injury and severe controlled cortical impact (CCI) can induce impairments in static and dynamic gait parameters. It is reported that the majority of deficits in gait-related parameters occur during the acute phase post-injury, as functional outcomes return toward baseline levels at chronic time points. In the present study, we carried out a longitudinal analysis of static, temporal and dynamic gait patterns following moderate-level CCI in adult male C57Bl/6J mice using the automated gait analysis apparatus, CatWalk. For comparison, we also performed longitudinal assessment of fine-motor coordination and function in CCI mice using more traditional sensorimotor behavioral tasks such as the beamwalk and accelerating rotarod tasks. We determined that longitudinal CatWalk analysis did not detect TBI-induced deficits in static, temporal, or dynamic gait parameters at acute or chronic time points. In contrast, the rotarod and beamwalk tasks showed that CCI mice had significant motor function impairments as demonstrated by deficits in balance and fine-motor coordination through 28 days post-injury. Stereological analysis confirmed that CCI produced a significant lesion in the parietal cortex at 28 days post-injury. Overall, these findings demonstrate that CatWalk analysis of gait parameters is not useful for assessment of long-term sensorimotor dysfunction after CCI, and that more traditional neurobehavioral tests should be used to quantify acute and chronic deficits in sensorimotor function.