JOURNAL ARTICLE

Bimodal odor processing with a trigeminal component at sub- and suprathreshold levels

Robert Pellegrino, Edda Drechsler, Cornelia Hummel, Jonathan Warr, Thomas Hummel
Neuroscience 2017 November 5, 363: 43-49
28739522
Odors are typically bimodal in nature, interacting with the olfactory and trigeminal systems. The trigeminal component may be noticed (e.g. menthol) or perceptually ignored, leading to different neural substrates being recruited during odor encoding. Therefore, the current study was designed to explore the perceptual and central-nervous activations in response to pleasant bimodal odors using functional magnetic resonance imaging (fMRI). In this study, healthy subjects were exposed to odorants alone (unimodal) or with a "cooling" trigeminal component (bimodal) at sub- and suprathreshold concentrations with a portable olfactometer in a 3T fMRI scanner. Within the scanner, subjects reported all odorants as pleasant and intensity increasing with trigeminal concentration. Many of the regions of interest [orbital frontal cortex (OFC), insula, thalamus, cerebellum, postcentral gyrus and cingulate cortex] were activated during bimodal odor conditions when contrasted with unimodal, and interestingly, most of these activations were seen prior to trigeminal perception (e.g. at a sub-threshold level). This includes large bilateral activations within the OFC, insula, cerebellum and parts of the cingulate cortex. Additionally, activation of the thalamus was seen early in the stages of bimodal odor encoding suggesting its role of mediating attention toward the presence of two stimuli. Lastly, intensity encoding during bimodal processing shows overlap of previously demonstrated simple trigeminal encoding areas (medial cingulate cortex) and the more complex olfactory encoding areas (bilateral insula, superior temporal gyrus, OFC, and cerebellum), but not the amygdala.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
28739522
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"