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The anterior olfactory nucleus pars medialis (mAON) provides cortical feedback to the olfactory bulb, but the behavioural relevance of these projections is unknown. Here, using opto- and chemogenetic approaches, the authors find the mAON bidirectionally modulates olfactory sensitivity and olfaction-dependent behaviours.
The lateral entorhinal cortex computes and transfers olfactory information from the olfactory bulb to the hippocampus and supports associative multimodal memories. Leitner et al. characterize the activity of odor-responsive cell types in this brain area and identify upstream and downstream brain areas to which olfactory information is conveyed.
The piriform cortex projects to multiple brain regions involved in diverse aspects of olfactory behavior but information about the organization of these outputs is lacking. Here the authors show that piriform neurons exhibit layer specific gene expression patterns that also define distinct projection targets.
In mice, the endocannabinoid system inhibits glutamatergic signalling from the olfactory cortex to the main olfactory bulb after fasting, increasing the detection of food odours and, consequently, enhancing food consumption.
Learned odor discrimination and generalization are reflected in patterns of ensemble activity in anterior piriform cortex, where learned discrimination between two odors reduces the correlation between their induced patterns.