Environmental influence on gene expression and recovery from cerebral ischemia

An emerging concept in neurobiology is that the adult brain retains a capac ity for plasticity and functional reorganization throughout the life span. Experimental data from electrophysiological, morphological and behavioral s tudies have documented experience dependent plasticity in the intact and in jured adult brain. Neuroimaging clinical studies indicate altered post stro ke functional activation patterns, usually including activation of the inta ct hemisphere. However, there is some disagreement regarding their function al significance and longitudinal studies correlating outcome and activation pattern are needed to solve some controversies. Postoperative housing of rats in activity stimulating environment after lig ation of the middle cerebral artery significantly enhances outcome. Gene ex pression for brain derived neurotrophic factor and Ca2+/calmodulin-dependen t protein kinase II, two substances with potential role in brain plasticity , show different patterns in animals housed in standard and in enriched env ironment. The functional significance of altered gene expression needs to b e evaluated.