Motor Cortex Response to Pleasant Odor Perception and Imagery: The Differential Role of Personality Dimensions and Imagery Ability

Abstract

BackgroundNeuroimaging studies have shown a complex pattern of brain activation during perception of a pleasant odor and during its olfactory imagery. To date, little is known regarding changes in motor cortex excitability during these tasks. Bergamot essential oil (BEO) is extensively used in perfumes and cosmetics for its pleasantness. Therefore, to further our understanding of the human sense of smell, this study aimed to investigate the effect of perception and imagery of a pleasant odor (BEO) on motor cortex using Transcranial magnetic stimulation (TMS).Materials and MethodsWe examined the primary motor cortex (M1) excitability during perception of a pleasant odor (BEO) or perception of odorless saline (experiment 1). Furthermore, we tested the effect of olfactory imagery (OI) of BEO on corticospinal excitability (experiment 2). The increase in motor evoked potential (MEP) amplitude was correlated with personality dimensions scores, pleasantness, vividness, and general imagery ability.ResultsThe results indicate that the corticospinal excitability changed after both perception and imagery of a pleasant odor (BEO). The correlation analysis shows an association with neuroticism personality trait (experiment 1) and with general olfactory imagery ability (experiment 2).ConclusionBoth perception of a pleasant odor and its olfactory imagery modulate motor cortex excitability. The enhanced brain activation is affected by specific individual characteristics. Overall, our findings provide physiological evidence for a complex interaction between the olfactory and motor systems.

fNIRS a novel neuroimaging tool to investigate olfaction, olfactory imagery, and crossmodal interactions: a systematic review

“…Fourteen of the reviewed papers weighed in on the debate regarding olfactory memory processes. Whilst only three of the reviewed papers actively studied olfactory memory ( Plailly et al, 2007 ; Meunier et al, 2014 ; Eek et al, 2023 ), eleven papers were able to apply their findings to contribute further knowledge to the discussion of olfactory memory ( Djordjevic et al, 2004 ; Bensafi and Rouby, 2007 ; Plailly et al, 2011 ; Hudry et al, 2014 ; Kollndorfer et al, 2015a ; Zhou et al, 2019 ; Callara et al, 2021 ; Infortuna et al, 2022 ; Torske et al, 2022 ; Muccioli et al, 2023 ; Perszyk et al, 2023 ). Memory of odours and olfactory experiences presents a unique case of memory encoding and recall compared to other sensory modalities ( Stevenson and Case, 2005 ; White, 2009 ; Eek et al, 2023 ).…”

Enhancing motor imagery detection efficacy using multisensory virtual reality priming

“…Moreover, sensory processing, including olfactory, has been shown to influence motor processing (Ebner, 2005 ). In a recent study using transcranial magnetic stimulation, the perception of a pleasant smell and its olfactory imagery showed to be associated with primary motor cortex excitability (Infortuna et al, 2022 ). The results were in line with those of Rossi et al ( 2008 ), which showed a cross-link between the olfactory and motor systems.…”