The olfactory cortex can learn to encode the subject’s spatial location as accurately as the hippocampus

The hippocampal-entorhinal network has an essential role in spatial cognition. Surprisingly, other brain regions not involved in this canonical spatial encoding network have been recently shown to modulate their neuronal activity according to the subject’s spatial location. This includes the remarkable discovery of spatial information encoded in the primary piriform olfactory cortex (PCx) of both rats and mice. Indeed, in a previous study and in work from our lab, rodents were trained in a task to associate olfactory and spatial cues to obtain a reward, and machine learning classifiers were applied to PCx activity to successfully classify the spatial context of each trial. This has been interpreted as spatial maps encoded in the olfactory cortex. However, can the animal’s spatial location across time be precisely decoded from PCx activity? Here, we study PCx and hippocampal neuronal activity of mice in different learning stages of this olfactory-spatial association task, and perform a series of spatial location decoding analyses. Our results indicate that the spatial location of the animal is encoded in the PCx once animals learn the task, but not before. Moreover the spatial encoding precision increases around behaviorally relevant locations, and decoding performances in the PCx and the hippocampus are comparable. We discuss how these results could contribute to our understanding of the role of the olfactory cortex in olfactory-cued spatial learning.