Presentation Details
| Chemosensory ERPs Suggest Peripherally Driven Olfactory–Trigeminal Interactions in Older Adults Sarah Brosse1, Olivier Fortier-Lebel2, Emilie Hudon2, Keven Lapointe1, Johannes Frasnelli1, 3, 4. 1Department of Anatomie, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.2Department of Psychology, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.3Research Center, Sacré Coeur Hospital, Montréal, QC, Canada.4Research Center, Institut universitaire de gériatrie de Montréal, Montréal, QC, Canada |
Abstract
The olfactory and intranasal trigeminal systems are closely connected and can mutually suppress and/or enhance each other, yet the mechanisms underlying their interaction remain poorly understood and have mostly been examined in young adults, despite age-related changes in both systems. To address this gap, we investigated olfactory–trigeminal interactions in 44 healthy older adults (66.3 ± 4.6 years; 29 women) using chemosensory event-related potentials (CSERPs) and the trigeminal localization task. Phenylethanol (PEA, 45%) and CO₂ (40%) were delivered with an olfactometer under four conditions: pure trigeminal (PT; CO₂), pure olfactory (PO; PEA), ipsilateral co-stimulation (IOT; PEA+CO₂ in the same nostril), and contralateral co-stimulation (COT; PEA+CO₂ in opposite nostrils). Brain responses were recorded with a 64-channel EEG system. LPC amplitudes were larger for all three trigeminal-containing conditions than for the PO condition (all p <0.001), with IOT exceeding PT (p = 0.028). Further, for trigeminal-containing conditions, LPC amplitudes positively correlated with performance on the trigeminal localization test. Together, these results highlight the prominent role of trigeminal input in chemosensory cortical processing and suggest that olfactory-trigeminal interactions are driven primarily by peripheral rather than central mechanisms. This study also provides normative CSERP data for healthy older adults.
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