Use-dependent growth of pyramidal neurons after neocortical damage

摘要: Unilateral damage to the forelimb representation area of sensorimotor cortex in adult rats increases dendritic arborization layer V pyramidal neurons contralateral homotopic cortex. Arbor size was maximum at approximately 18 d postlesion, following which there a partial elimination, or pruning, processes. These neural changes were closely associated with behavioral events. The overgrowth dendrites related time disuse (to lesion) and over-reliance on ipsilateral for postural exploratory movements. pruning return more symmetrical use forelimbs. To investigate possibility that lesion-induced asymmetries motor behavior contributed changes, movements lesion restricted during period through one-holed vests. This interfered increase arborization. In contrast, animals allowed both forelimbs, only lesion, showed expected increases. When sham-operated forced one forelimb, no significant found. Therefore, neither nor asymmetrical limb alone could account overgrowth--it depended lesion-behavior interaction. Furthermore, greater impairments found when growth blocked, suggesting and/or limb-use functional recovery from cortical damage. Finally, second experiment, immobilization impaired did not prevent elimination Thus, processes simply use. There may be early after brain marked structural can occur presence adequate demand.