Enriched environment improves the cognitive effects from traumatic brain injury in mice.

To date, there is yet no established effective treatment (medication or cognitive intervention) for post-traumatic brain injury (TBI) patients with chronic sequelae. Enriched environment (EE) has been recognized of importance in brain regulation, behaviour and physiology. Rodents reared in, or pre-exposed to EE, recovered better from brain insults. Using the concussive head trauma model of minimal TBI in mice, we evaluated the effect of transition to EE following a weight-drop (30g or 50g) induced mTBI on behavioural and cognitive parameters in mice in the Novel Object Recognition task, the Y- and the Elevated Plus mazes. In all assays, both mTBI groups (30g, 50g) housed in normal conditions were equally and significantly impaired 6 weeks post injury in comparison with the no-mTBI (p<0.001 and p<0.03, respectively) and the mTBI+EE groups (p<0.001 for the 30g, and p<0.017 for the 50g). No differences were found between the control and the EE mice. Two separate finding emerge: (1) the significantly positive effects of the placement in EE following mTBI, on the rehabilitative process of the tested behaviours in the affected mice; (2) the lack of difference between the groups of mice affected by 30g or by 50g. Further studies are needed in order to characterize the exact pathways involved in the positive effects of the EE on mice recovery from mTBI. Possible clinical implications indicate the importance of adapting correlates of EE to humans, i.e., prolonged and intensive physical activity - possibly combined with juggling training and intensive cognitive stimulation.