GABAergic control of newborn neurons in the adult dentate gyrus

SCHINDER AF

Ginebra, Suiza

Simposio; Simposio “GABA and adult neurogenesis”, FENS FORUM; 2008

Federation of European Neuroscience Societies (FENS)

It has been proposed that adult neurogenesis acts as a mechanism whereby new neurons with a unique functionality become incorporated into the preexisting hippocampal circuitry. Unique traits of adult-born neurons may arise from their intrinsic properties or from a distinctive pattern of connectivity. GABAergic interneurons of the hippocampus are highly diverse and complex, and control the activity of principal excitatory neurons. We have recently investigated whether fully mature new neurons acquire a unique pattern of GABAergic connectivity. Neurons born at different developmental stages were labeled using retroviral transduction with red and green fluorescent proteins, and their somatic, proximal and distal GABAergic inputs were compared using electrophysiological techniques and paired statistical analyses. Dentate granule cells born in the embryonic, postnatal and adult brain exhibit remarkably similar profiles of GABAergic activity. Excitatory inputs are also indistinguishable among the different neuronal populations, underscoring a tight control of afferent connectivity and inhibition-excitation balance for neurons born in different environments and developmental stages. The mechanisms underlying this delicate balance are currently under study.