Presentation Details
| Olfactory input modulates peripheral trigeminal responses during mixed stimulation. Keven Lapointe1, Johannes Frasnelli1, 2, 3. 1Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.2Research Center, Hôpital du Sacré-Coeur de Montréal, Montréal, QC, Canada.3Research Center, Institut universitaire de gériatrie de Montréal, Montréal, QC, Canada |
Abstract
The trigeminal system, alongside smell and taste, constitutes a third chemosensory modality. It is responsible for sensations such as warmth, cooling, and tingling. The olfactory and trigeminal systems interact at multiple levels to modulate odor perception, from the nasal mucosa to central structures. More specifically, olfaction appears to amplify trigeminal perception, whereas trigeminal activation tends to reduce olfactory perception. However, the mechanisms underlying this interaction remain poorly characterized, particularly at the peripheral level. A better understanding could clarify alterations observed in olfactory disorders and advance our knowledge of human chemoperception. We used negative mucosal potentials (NMP) to record peripheral trigeminal activity with custom-made Ag/AgCl electrodes placed in the respiratory epithelium. Four experimental conditions were tested: pure olfactory (2-phenylethanol, PEA), pure trigeminal (CO₂), ipsilateral olfactory-trigeminal (PEA+CO₂ in the same nostril; IOT), and contralateral olfactory-trigeminal (PEA and CO₂ in opposite nostrils; COT). Repeated measures ANOVA revealed a significant effect of stimuli (Pillai’s V = .70, F2,7 = 8.13, p = .015, η2p = .70). Bonferroni post-hoc comparisons indicated that the IOT condition elicited significantly higher amplitudes than CO₂ alone (p = .023) but not COT (p = .108), while the COT condition also did not produce higher amplitudes than CO₂ alone (p = .105). Together, these findings suggest that peripheral trigeminal responses are modulated by olfactory co-stimulation, highlighting a peripheral mechanism by which odor perception could also be shaped. In conclusion, this supports the existence of an early peripheral interaction preceding central integration between the olfactory and trigeminal systems.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.
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