Modulation of olfactory-driven behavior by nutritional state: role of the olfactory cortex

Olfaction is one of the major sensory modalities that regulate food consumption. Conversely, feeding states modulate olfactory sensitivity. Fasting increases olfactory sensitivity, whereas satiety decreases the ability to detect odors. Moreover, metabolic disorders and body weight also modify the physiological response to odors. An increasing body of evidence indicates that this interplay is mediated by a direct action of metabolic peptides and hormones on the olfactory system specifically the olfactory mucosa and the olfactory bulb, the first two steps of olfactory perception. However, nutritional modulation of olfactory cortices and higher olfactory processing, such as odor discrimination and memory, has been only scantily explored.

In this study, we combined behavioral assessments, immunohistochemistry, intracerebral microinjections and electrophysiology to demonstrate that feeding states can modulate complex olfactory behavior by an action of metabolic hormones on the olfactory cortex.