Bidirectional regulation of mitochondrial gene expression during developmental neuroplasticity of visual cortex

The first several months of life are a critical period for neuronal plastic ity in the visual cortex, during which anatomical and physiological develop ment depends upon visual experience. Rearing in darkness slows the time cou rse of this critical period, such that at 5 weeks normal cats are more plas tic than dark. reared cats, while at 20 weeks dark-reared cats are more pla stic. This study reports the identification of a subset of mitochondrial ge nes that are regulated in this manner. Opponent patterns of bidirectional e xpression were found: several genes (ATPase 6, cytochrome b, NADH dehydroge nase subunits 4 and 2) showed elevation in normal cats at 5 weeks and in da rk-reared cats at 20 weeks ("Plasticity" genes); others (NADH dehydrogenase subunits 3 and 5) showed the opposite ("anti-plasticity" genes). These fin dings add a new dimension to the growing evidence that changes in mitochond rial gene expression are involved in the neuroplastic response. (C) 2001 Ac ademic Press.