Article

Environmental enrichment (EE) enhances motor and cognitive
performance after traumatic brain injury (TBI). However, whether the EE-mediated
benefits are time dependent and task specific is unclear.
A preliminary study, in
which only half of the possible temporal manipulations were evaluated, revealed
that the beneficial effects of enrichment were only observed when provided
concurrently with specific training (ie, motor or cognitive), suggesting
task-specific dependence. OBJECTIVE: To further assess the effects of time of
initiation and duration of EE on neurobehavioral recovery after TBI by evaluating
and directly comparing all the temporal permutations. METHODS: Anesthetized adult
male rats received either a cortical impact or sham injury and were then randomly
assigned to 8 groups receiving continuous or early and delayed EE with either 1
or 2 weeks of exposure. Functional outcome was assessed with established motor
(beam-balance/walk) and cognitive (Morris water maze) tests on postinjury days 1
to 5 and 14 to 18, respectively. RESULTS: Motor ability was enhanced in the TBI
groups that received early EE (ie, during testing) versus standard housing. In
contrast, acquisition of spatial learning was facilitated in the groups receiving
delayed EE (ie, during training). CONCLUSIONS: These data support the conclusion
from the previous study that EE-mediated functional improvement after TBI is
contingent on task-specific neurobehavioral experience and extends those
preliminary findings by demonstrating that the duration of enriched exposure is
also important for functional recovery.

Langue : ANGLAIS