Prediction of Post-Concussive Behavioral Changes in a Rodent Model Based on Head Rotational Acceleration Characteristics

Quantifying injury tolerance for concussion is complicated by variability in the type, severity, and time course of post-injury physiological and behavioral changes. The current study outlined acute and chronic changes in behavioral metrics following rotational acceleration-induced concussion in rats. The Medical College of Wisconsin (MCW) rotational injury model independently controlled magnitude and duration of the rotational acceleration pulse. Increasing rotational acceleration magnitude produced longer recovery times, which were used in this study and our prior work as an assessment of acute injury severity. However, longer duration rotational accelerations produced changes in emotionality as measured using the elevated plus maze. Cognitive deficits were for the most part not apparent in the Morris water maze assessment, possibly due to the lower severity of rotational acceleration pulses incorporated in this study. Changes in emotionality evolved between acute and chronic assessments, in some cases increasing in severity and in others reversing polarity. These findings highlight the complexity of quantifying injury tolerance for concussion and demonstrate a need to incorporate rotational acceleration magnitude and duration in proposed injury tolerance metrics. Rotational velocity on its own was not a strong predictor of the magnitude or type of acute behavioral changes following concussion, although its combination with rotational acceleration magnitude using multivariate analysis was the strongest predictor for acute recovery time and some chronic emotional-type behavioral changes.