Sensorimotor impairment and recovery of function in brain-damaged rats: reappearance of symptoms during old age.

Following unilateral lesions in the posterior-lateral hypothalamic area, rats displayed impaired orienting behavior to tactile stimuli placed on the contralateral side of the body, whereas sham-operated animals showed no sensorimotor impairment. Recovery from this impairment occurred during the first postoperative month. As the animals became senescent, there was a reinstatement of contralateral sensorimotor impairment in the brain-damaged animals. Although preliminary, these data may have important implications for the study of aging-dependent neurological and psychiatric disorders.