Olfactory Stimulation Modulates Visual Perception Without Training

Abstract

Considerable research shows that olfactory stimulations affect other modalities in high-level cognitive functions such as emotion. However, little known fact is that olfaction modulates low-level perception of other sensory modalities. Although some studies showed that olfaction had influenced on the other low-level perception, all of them required specific experiences like perceptual training. To test the possibility that olfaction modulates low-level perception without training, we conducted a series of psychophysical and neuroimaging experiments. From the results of a visual task in which participants reported the speed of moving dots, we found that participants perceived the slower motions with a lemon smell and the faster motions with a vanilla smell, without any specific training. In functional magnetic resonance imaging (fMRI) studies, brain activities in the visual cortices [V1 and human middle temporal area (hMT)] changed based on the type of olfactory stimulation. Our findings provide us with the first direct evidence that olfaction modulates low-level visual perception without training, thereby indicating that olfactory-visual effect is not an acquired behavior but an innate behavior. The present results show us with a new crossmodal effect between olfaction and vision, and bring a unique opportunity to reconsider some fundamental roles of olfactory function.

Functional connectivity patterns in parosmia

“…Decreased FC was observed between the area surrounding the anterior as well as the medial dorsal part of thalamus and MVN in patients with a higher degree of parosmia (Par 2–3). A recent study contemplated the role of visual network and olfaction and found that olfaction modulates low-level visual inputs [ 43 ]. The authors of the paper focus on the cross-modal effect of various senses.…”

Does Olfactory Training Improve Brain Function and Cognition? A Systematic Review

“…Others have found that exposure to commercially available essential oils in real-time can improve memory, alertness, vigilance, self-perception, pain perception, and mood (Johnson, 2011 ). Similarly, Tsushima et al ( 2021 ) found that exposure to a lemon odorant and vanilla odorant modulated positively and negatively, respectively, low-level visual perception, which suggests some innate characteristics of odorants on perception and cognitive function.…”

Optoelectronic Synapses Based on MXene/Violet Phosphorus van der Waals Heterojunctions for Visual-Olfactory Crossmodal Perception

“…The perception and memory processes of human are crossmodal, that is, the information input from different sense organs will interact in a synergistic or antagonistic manner, thereby strengthening the ability to perceive the environment or memory. For example, Tsushima et al found that fragrance can change the human perception of the moving speed of pictures through psychological and physiological experiments [57]. Therefore, optoelectronic synapses with visual-olfactory crossmodal perception for developing biomimetic visual perception and memory are highly desired.…”