Granule cells born in middle-aged mice present high levels of plasticity

BUTTNER KA; SULKES JN; SCHINDER AF; TRINCHERO MF

Buenos Aires

Congreso; FALAN; 2016

Society for Research in Neuroscience

Adult hippocampal neurogenesis generates new excitatorygranule cells (GCs) in the dentate gyrus throughout life.Adult neurogenesis decreases with age. However, theeffects of aging on the quality and functional capacity ofnew GCs remain unclear. To address this question, we useda GFP-expressing retrovirus to label neural progenitor cellsin aging mice and performed a morphological analysisat different times post-injection. We observed that thematuration rate decreases substantially as mice get older. Wehypothesized that enhancing hippocampal activity mightact as a positive modulator of GC development under agingconditions. To test this idea, we first evaluated the effectof voluntary exercise (running wheel) in young adult mice(two months old) and middle-aged mice (8 months old).Exercise in middle-aged mice accelerated maturation ofdeveloping GCs to a remarkable extent. Spatial explorationin an enriched environment (EE), which is also a behaviorthat promotes activation of hippocampal circuits, renderedsimilar effects in developing GCs of aging mice to thoseof voluntary exercise. In particular, running and EE bothpromoted dendritic growth and increased spine density,highlighting an enhancement in functional connectivity.Our results suggest that, contrary to most predictions, newGCs born in aging mice bear a large potential for plasticity.Future experiments will shed light on the mechanismsunderlying this phenomenon.