A comparison of two cognitive test paradigms in a penetrating brain injury model

Abstract

A rat model of penetrating ballistic-like brain injury (PBBI) was recently established to study military-relevant severe traumatic brain injury (TBI). The purpose of this study was to conduct a side-by-side evaluation of two well-established cognitive testing paradigms: the novel object recognition (NOR) task and the Morris water maze (MWM) task. Accordingly, male Sprague-Dawley rats were subjected to PBBI and their cognitive abilities were assessed at 7 and 21 days post-PBBI. Although PBBI animals had more difficulty completing both tasks compared to sham animals, their performance on the NOR task was confounded by a high degree of within-group variability that was likely due to attention deficits produced by the injury. In contrast, PBBI produced consistent, significant spatial learning deficits in the MWM task. Overall, these results suggest that the MWM task provides a more appropriate cognitive test for the PBBI model that would be useful for testing promising neuroprotective therapeutics.