A food-sensitive olfactory circuit drives anticipatory satiety
1 Max Planck Institute for Metabolism Research, Cologne, Germany
2 Francis Crick Institute, London, UK
Food sensory perception has emerged as a potent regulator of specialized feeding circuits; yet, the consequences on feeding behaviour and the underlying neuronal basis remain poorly understood. Here, we reveal a sensory pathway that coordinately integrates food odours to control forthcoming nutrient intake. Unbiased whole-brain mapping of food odours-induced brain activity revealed a potent activation of the medial septum (MS), where food odours selectively activate MS glutamatergic neurons (MSVGLUT2). Characterization of the activity dynamics of MSVGLUT2 neurons uncovered a biphasic modulation of their neuronal activity with a transient activation upon detection of food odours and a long-lasting inhibition following food ingestion, independent of the caloric value and identity of the food. MSVGLUT2 neurons receive direct projections from the olfactory bulb (OB) and acute optogenetic stimulation of OB –>MS projections exclusively before the dark phase decreased feeding in lean mice. However, OB–>MS optogenetic stimulation in diet-induced obese mice failed to reduce feeding, suggesting the involvement of this pathway in calorie-rich diet-induced hyperphagia and obesity development. Altogether, our study uncovered a novel sensory circuit by which the organism integrates olfactory food cues to prime satiety at the outset of a meal.