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bioRxiv · 10.1101/2025.11.24.690198

Glomerulus-specific inhomogeneity of the basal activity map in the olfactory bulb supports olfactory-driven behavior

Fink, S.·Fomin-Thunemann, N.·Tzeng, W.-Y.·Figarella, K.·Kamari, F.·Kovalchuk, Y.·Garaschuk, O.
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Abstract

Glomeruli are signal-processing units of the olfactory bulb (OB), playing a key role in many OB computations, including contrast enhancement, gain control, and odorant-selective habituation. In awake mice, we uncover an extremely stable inhomogeneous map of basal glomerulus-specific activity as a background against which olfactory signal processing is performed. This activity is strongly driven by (i) centrifugal cholinergic projections, (ii) endogenous, and (iii) airflow-evoked spiking of olfactory sensory neurons and, to a small extent, (iv) by the odor environment. Importantly, early olfactory impairment in a mouse model of Alzheimers disease is parallelled by the loss of glomerular map inhomogeneity and diminished cholinergic innervation. These results reveal an important layer in the signal-processing network of the OB, likely acting by increasing the variance in and dynamic range of the system via glomerulus-specific functional inhomogeneity. TeaserA new layer in the signal-processing network of the olfactory bulb supports olfactory-driven behavior.

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Fink, S., Fomin-Thunemann, N., Tzeng, W.-Y., Figarella, K., Kamari, F., Kovalchuk, Y., Garaschuk, O.. 2025-11-26. Glomerulus-specific inhomogeneity of the basal activity map in the olfactory bulb supports olfactory-driven behavior. https://doi.org/10.1101/2025.11.24.690198

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