Effects of environment on enhancing functional plasticity following cerebral ischemia.

Given the brain's capacity to recover from injury, plasticity may be enhanced following cerebral ischemia through environmental manipulation. Thus, the purpose of this study was to (1) determine the effects of early exposure to an enriched environment following ischemia on functional plasticity and (2) examine the relationship between morphological and behavioral plasticity. Adult female rats (n = 38) were divided into ischemia and control groups. Each group was further randomized to either standard (SC) or enriched conditions (EC). After 4 days of environmental exposure, rats were tested for 6 days in the water maze. Control and ischemia rats exposed to EC have increased total dendritic length (P < 0.05) as well as increased number of dendritic segments in the apical (P < 0.05) region of the hippocampal area compared to those housed in SC; furthermore, increased dendritic spine density in the apical (P < 0.05) region was also seen. Behavioral testing showed that ischemia rats exposed to SC have longer swim latencies (P < 0.05) and greater directional heading errors (P < 0.05) than ischemic rats exposed to EC; the latter group performed similar to controls. It is concluded that EC may be a potentially useful therapy in the recovery of spatial memory impairments seen after ischemia.