A local feedback circuit mediates integration of adult-born dentate granule cells promoted by experience

DIEGO D. ALVAREZ *; DAMIANA GIACOMINI *; SUNG M. YANG; MARIELA TRINCHERO; ALEJANDRO F. SCHINDER

Mar del Plata

Congreso; XXX Congreso de la Sociedad Argentina de Neurociencias (SAN); 2015

Adult-born dentate granule cells (GCs) develop and integrate into the local networks in a process that lasts several weeks. It has been shown that network activity modulates maturation of adult-born neurons. Here we show that developing GCs display a critical period previous to the onset of glutamatergic synaptogenesis whereby they are prone to modulation by activity. A brief (48 h) exposure to enriched environment within this critical period is sufficient to accelerate maturation and functional integration of new GCs. Accelerated integration was also found upon brief direct activation of new GCs during the critical period using the synthetic G-coupled receptor hM3Dq. In addition, mature GCs were activated by means of the hM3Dq receptor to test the influence of local circuits on developing GCs. Indeed, activation of mature GCs by the synthetic ligand accelerated GC integration. In agreement with recent works we propose that parvalbumin-expressing GABA interneurons (PV) are responsible of controlling neuronal maturation. Interestingly, ex-vivo activation of PV interneurons induced a postsynaptic response in developing neurons. Our results suggest that during cognitive tasks, GCs activate PV interneurons, which, in turn, promote functional recruitment of new cohorts of developing GCs.