Matia, Allison C.. Interactions between odorants in the activity of olfactory sensory neurons and periglomerular interneurons in the mouse olfactory bulb. Retrieved from https://doi.org/doi:10.7282/t3-p6j6-5d88
DescriptionSensory stimuli are never encountered in isolation. Our senses are barraged by many stimuli at once, and these stimuli can interact with each other. The olfactory system may be particularly subject to these stimulus-stimulus interactions because of the overlapping selectivity profiles of odor receptors. Simultaneous presentation of multiple odorants can produce perceptions that differ radically from the odorants individually, a phenomenon known as “mixture interactions.” However, the biological explanation for these interactions has been elusive. Modern optical neurophysiology technologies offer a novel opportunity to visualize neural representations of olfactory stimuli and thus permit the direct observation of neural interactions between odorants. These interactions are typically presumed to occur at the periphery, where odorants compete for olfactory receptor binding sites. However, these interactions could potentially also occur within the brain’s olfactory bulb, where complex local circuitry and centrifugal inputs from olfactory cortices appear positioned to shape odorant-evoked activity based on specific odorant conjunctions. The established, putatively odor receptor-dependent mixture interaction between isoamyl acetate and whiskey lactone was investigated in olfactory sensory neurons in vivo, but a compelling peripheral interaction between these odors was not observed. Circuit-level mixture interactions within the olfactory bulb between lemon-like odors were also explored. Sublinear summation and co-inhibition of these odors was observed in GABAergic periglomerular interneurons. Our findings shed light on odorant mixture interactions both at the periphery and within the central nervous system.