Even if aging does not influence neuronal death, physiological stimuli can still be used to increase survival in senescent animals. In particular, living in an enriched environment that provides access to social and inanimate stimuli, such as toys, proved to be the strongest physiological condition increasing the survival of neurons in young and aged mice [36,144] suggesting that the aged brain retains a certain level of neuroplasticity. Similar results were obtained after long-term exposure to enriched environment indicating an overall increase in the neuronal survival baseline rather than an acute response to new stimuli [37]. Importantly, increased neuronal survival in old animals positively correlated with a better performance in spatial memory tests [36,37] end even if the molecular mechanism underlying this correlation is largely unknown, recent studies suggest a role of steroid hormone receptors [82].
http://impactaging.com/papers/v4/n3/full/100446.html
