A Lateral View of the Sense of Smell
– September 2019 issue of PLOS | Biology
The mammalian olfactory bulb plays an essential role in odor processing during the perception of smell, but most studies have focused on the dorsal olfactory bulb, which contains only a quarter of all glomeruli. Here, Keeley Baker, Justus Verhagen and co-authors use imaging of the lateral olfactory bulb to reveal new properties in smell processing.
Lateral glomeruli became active in a dorso-ventral (D-V) sequence upon odor inhalation, unlike the anterio-posterior (A-P) activity wave typical of the dorsal glomeruli.
Across the entire D-L bulb, the spatial organization of these dynamics can be explained neither by the purely mechanosensitive dynamics (to breathing clean air) nor by the response amplitudes across glomeruli.
These dynamics can be explained by a combination of zonal receptor distributions, associated OB projections, and air flow paths across the epithelium upon inhalation. Remarkably, they also found that a subset of OSN glomeruli in the venrtral lOB was highly sensitive to extranasal air pressure changes, a response type that has not been reported in dorsal glomeruli.