Infortuna Carmenrita, Gualano Francesca, Freedberg David, Patel Sapan P, Sheikh Asad M, Muscatello Maria Rosaria Anna, Bruno Antonio, Mento Carmela, Chusid Eileen, Han Zhiyong, Thomas Florian P, Battaglia Fortunato
Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Policlinico Universitario "G. Martino", University of Messina, Messina, Italy.
Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, NJ, United States.
Front Hum Neurosci. 2022 Jul 12;16:943469. doi: 10.3389/fnhum.2022.943469. eCollection 2022.
Neuroimaging 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).
We 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.
The 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).
Both 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.
神经影像学研究表明，在感知愉悦气味及其嗅觉想象过程中，大脑激活模式复杂。迄今为止，对于这些任务期间运动皮层兴奋性的变化知之甚少。佛手柑精油（BEO）因其宜人的气味而广泛用于香水和化妆品中。因此，为了进一步了解人类的嗅觉，本研究旨在使用经颅磁刺激（TMS）研究愉悦气味（BEO）的感知和想象对运动皮层的影响。
我们在感知愉悦气味（BEO）或无味盐水期间检查了初级运动皮层（M1）的兴奋性（实验1）。此外，我们测试了BEO的嗅觉想象（OI）对皮质脊髓兴奋性的影响（实验2）。运动诱发电位（MEP）幅度的增加与人格维度得分、愉悦度、生动度和一般想象能力相关。
结果表明，在感知和想象愉悦气味（BEO）后，皮质脊髓兴奋性发生了变化。相关分析显示与神经质人格特质（实验1）和一般嗅觉想象能力（实验2）有关。
愉悦气味的感知及其嗅觉想象均调节运动皮层兴奋性。增强的大脑激活受特定个体特征的影响。总体而言，我们的研究结果为嗅觉和运动系统之间的复杂相互作用提供了生理学证据。
