Neuromodulators in the processing of afferent inputs in the dentate gyrus

MORA B. OGANDO; DANIELA DI BELLA; ANTONIA MARIN BURGIN

Mar del Plata

Congreso; Sociedad Argentina de Neurociencias; 2015

Neuromodulators in the processing of afferent inputs in the dentate gyrusNeurogenesis 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 widely 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 balance between excitation and inhibition results in a pattern of population activity. Immature 4 week old GC have specific processing features, as they exhibit a higher excitation to inhibition 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 excitation to inhibition balance in GC, providing a new level of plasticity for information processing.Using electrophysiological techniques, we evaluated the effect of serotonin and acetylcholine in the DG input processing, both during adult neurogenesis and during development. Our results suggest that neuromodulators can selectively affect one population of GC in the DG, modifying their relative contribution to the output signal towards CA3.