Deficits and recovery of body stabilization during acrobatic locomotion after focal lesion to the somatosensory cortex: a kinematic analysis combined with cortical mapping

摘要

Numerous studies have investigated functional changes after the induction of large neocortical lesions. By contrast, there are fewer reports of sensorimotor dysfunction after focal neocortical injury. In a previous report, we documented the effects of a restricted unilateral injury to the hand representational zone of area 3b in the primary somatosensory (SI) cortex of monkeys trained on a manual dexterity task (XERRI et al, 1998). We found that this lesion induced transient purely tactile deficits, but enduring sensorimotor impairment. In the early postoperative period, deficits in the precision of ballistic movement, inaccurate hand positioning, disruption of grip formation and inability to execute independent and precisely coordinated finger movements were observed. These sensorimotor deficits subsided and manual dexterity gradually improved over a period of several weeks, until complete recovery was achieved. In addition, we reported correlative changes in the organization of electrophysiological maps in peri-lesion zones of area 3b, as well as in areas 1 and 3a interconnected with the region of the direct damage. This cortical map remodelling was clearly related to rehabilitative effects of training on the dexterity task, presumably through experience-dependent mechanisms of neuroplasticity.