Opening Lecture, Paul Broca Conference

SCHINDER AF

Congreso; 12th Colloque of the French Society for Neuroscience, Montpellier, Francia,; 2015

The role of adult neurogenesis in information processing in the hippocampusAmong cortical structures, the dentate gyrus of the hippocampus presents a unique degree of plasticity conferred by the continuous production of new principal neurons, the adult-born dentate granule cells (GCs). Thousands of new GCs are added every day, generating millions of new connections that remodel the existing dentate circuits. Why this particular brain region presents such unique type of plasticity is a puzzling and fascinating problem. In recent years, evidence has accumulated indicating that manipulations that decrease adult neurogenesis can impair spatial discrimination, suggesting that new neurons are relevant for this process. However, how new GCs precisely impinge in the dentate network to improve discrimination in a manner that impacts on animal behavior is a question that has remained unclear. Adult-born GCs require almost two months before reaching a mature phenotype. Over several years, we and other colleagues have built a spatio-temporal map of input/output connectivity of developing neurons, revealing that new GCs go through discrete functional profiles that emerge from the combination of intrinsic and network properties. We are now converging towards the notion that adult neurogenesis serves as a mechanism for the continuous generation of new cohorts of young and highly plastic neurons that integrate in the network in a manner that is shaped by ongoing experience. In my talk, I will focus on recent experimental data on how local microcircuits change by adult neurogenesis, discuss its implications in hippocampal function, and propose a model on how newborn GCs may contribute to memory encoding.