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Olfactory-trigeminal Integration in the Primary Olfactory Cortex

Overview
Journal Hum Brain Mapp
Publisher Wiley
Specialty Neurology
Date 2024 Jul 4
PMID 38962966
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Abstract

Humans naturally integrate signals from the olfactory and intranasal trigeminal systems. A tight interplay has been demonstrated between these two systems, and yet the neural circuitry mediating olfactory-trigeminal (OT) integration remains poorly understood. Using functional magnetic resonance imaging (fMRI), combined with psychophysics, this study investigated the neural mechanisms underlying OT integration. Fifteen participants with normal olfactory function performed a localization task with air-puff stimuli, phenylethyl alcohol (PEA; rose odor), or a combination thereof while being scanned. The ability to localize PEA to either nostril was at chance. Yet, its presence significantly improved the localization accuracy of weak, but not strong, air-puffs, when both stimuli were delivered concurrently to the same nostril, but not when different nostrils received the two stimuli. This enhancement in localization accuracy, exemplifying the principles of spatial coincidence and inverse effectiveness in multisensory integration, was associated with multisensory integrative activity in the primary olfactory (POC), orbitofrontal (OFC), superior temporal (STC), inferior parietal (IPC) and cingulate cortices, and in the cerebellum. Multisensory enhancement in most of these regions correlated with behavioral multisensory enhancement, as did increases in connectivity between some of these regions. We interpret these findings as indicating that the POC is part of a distributed brain network mediating integration between the olfactory and trigeminal systems. PRACTITIONER POINTS: Psychophysical and neuroimaging study of olfactory-trigeminal (OT) integration. Behavior, cortical activity, and network connectivity show OT integration. OT integration obeys principles of inverse effectiveness and spatial coincidence. Behavioral and neural measures of OT integration are correlated.

References
1.
Karunanayaka P, Lu J, Yang Q, Sathian K . Olfactory Costimulation Influences Intranasal Somatosensory Perception. Multisens Res. 2021; 33(7):723-736. DOI: 10.1163/22134808-bja10008. View

2.
Tremblay C, Frasnelli J . Olfactory-Trigeminal Interactions in Patients with Parkinson's Disease. Chem Senses. 2021; 46. PMC: 8244988. DOI: 10.1093/chemse/bjab018. View

3.
Beauchamp M . See me, hear me, touch me: multisensory integration in lateral occipital-temporal cortex. Curr Opin Neurobiol. 2005; 15(2):145-53. DOI: 10.1016/j.conb.2005.03.011. View

4.
Courtiol E, Wilson D . The Olfactory Mosaic: Bringing an Olfactory Network Together for Odor Perception. Perception. 2016; 46(3-4):320-332. PMC: 5362339. DOI: 10.1177/0301006616663216. View

5.
Isaacson J . Odor representations in mammalian cortical circuits. Curr Opin Neurobiol. 2010; 20(3):328-31. PMC: 2896888. DOI: 10.1016/j.conb.2010.02.004. View