Interaction among excitatory and inhibitory circuits in the hippocampus and its modulation during adult neurogenesis

LUIS MORELI; DIEGO ARRIBAS; GUILLERMO LANUZA; MORA B. OGANDO; ANTONIA MARIN-BURGIN; LUCIANO BRUM

Congreso; SAN 2017; 2017

Neurogenesis in the adulthood continuously provides the dentate gyrus (DG) of the hippocampus with pools of granule cells (GC) which integrate into the preexisting network.The maturation process of this newborn neurons is well characterized and is similar to the maturation of GC during development. It has been shown that newly born GC are necessary for many types of memory but how these neurons contribute to the hippocampal function is under intense investigation.As inputs arrive to DG, they activate both excitatory and inhibitory neurons, and the excitation to inhibition (E/I) balance results in a pattern of population activity. Immature 4 week old GC have specific processing features, as they exhibit a higher E/I balance compared to mature GC. Thus, even though this population of neurons represents only 3-6 % of the total GC, their contribution to processing could be important due to their higher activity, their higher spiking rate and their higher plasticity. Neuromodulatory circuits projecting to the DG could modulate E/I balance in GC, providing a new level of plasticity for information processing of afferent stimulation.