Some functional recovery and behavioral sparing occurs independent of task-specific practice after injury to the rat's sensorimotor cortex.

These experiments on rats evaluated whether recovery of competence in certain motor tests could be enhanced by practice begun soon after traumatic brain injury (TBI). Before TBI, rats were pre-trained to cross a flat and a pegged beam. Anesthetized animals received a right sensorimotor cortex TBI. One group began task-specific testing (flat and pegged beams) on day 1 after injury and repeated 13 times in 35 days by which time functional recovery occurred. Paw preference was evaluated eight times during the 35 day period, beginning the third day after injury. A second group of injured rats remained in their home cage without any testing for 35 days after injury. From day 35 they were tested 13 times over the next 35 days on both beam tests and eight times on the paw preference test. At day 35 those rats that remained in their home cage without testing (task-specific practice) performed as well on the flat beam as the rats that began testing 1 day after injury. By day 37, their third test day, the untested rats performed as well as the tested rats on the pegged beam. Paw preference was the same in both groups of rats. These results were compared to sham-operated controls. Post-injury performance as measured by these tests indicated that most of the recovery occurred without task-specific practice. However, task-specific practice was necessary to achieve optimum performance on both beam tests. This implies that neural reorganization occurred independent of any practice. Task specific practice served to 'fine tune' the rat's performance after 35 days.