Follow your nose: the computational role of olfaction in spatial memory and navigation

Abstract

Olfactory stimuli permit perception of distant objects and odors are intimately connectedto memories. The brain must integrate olfactory stimuli with the time and place that they were experienced, but the brain lacks receptors for time or place. How does the olfactory system link odors to spatial memory in order to adaptively navigate complex environments? We find that the mouse olfactory system is modulated by multiple aspects of the animal's environment as early as the olfactory bulb, the first synapse in the olfactory system. The spiking activity of olfactory bulb neurons encodes the sniffing behavior at both a subsecond, intersniff timescales as well as longer timescale breathing rhythms. Additionally, we find that olfactory bulb neurons represent an animal’s allocentric location. Through task-trained recurrent neural network simulations, we hypothesize that this olfactory-spatial interaction depends on the behavioral demands of a simulated searcher to adaptively support localization. These findings provide novel insights into the nature of olfactory perception in awake behaving animals that motivate a more integrative approach to the study of olfactory physiology.