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The adult mammalian brain retains a remarkable capacity to produce new neurons throughout life. Adult neurogenesis is most prominent in the mammalian forebrain where neural stem cells (NSCs) located in a specialized micro-environment need to integrate multiple signals to remain quiescent or be activated to generate neuronal precursors and glia. The neuronal precursors migrate long distances to reach the olfactory bulb (OB) where they integrate into adult neuronal networks and play an important role in the odor processing.

In the first part of the talk, I will discuss some of our unpublished data aiming to determine how adult NSCs integrate and decode various microenvironmental signals that drive them to divide or to remain poised for future needs. Of the many intracellular pathways that are at play in somatic stem cells of different organs, Ca2+ signaling is emerging as a key signaling hub on which multiple extracellular cues may impinge to dynamically regulate Ca2+ fluctuations and steady-state intracellular levels, which in turn regulate somatic stem cell quiescence and activation. Using 2photon Ca2+ imaging in thin NSC processes ex vivo in brain slices followed by iterative immunostaining to identify all niche elements that are in contact with imaged cells, our data suggest that adult NSCs integrate inputs from multiple niche elements at the level of their processes by dynamically regulated spatio-temporal pattern of Ca2+ fluctuations.

In the second part of the talk, I will discuss the role of substantia innominata (SI), a small nucleus in the basal forebrain in the odor processing. Using mini-endoscopic Ca2+ imaging in freely behaving mice combined with measurements of active sniffing, our data demonstrate that neuronal activity in SI is specifically tuned to active sniffing and that these neurons project back into OB to synapse with specific type of interneurons and regulate odor processing.

This seminar will take place both in-person and online. Details in attached poster