Time course of odorant- and trigeminal-induced activation in the human brain: an event-related functional magnetic resonance imaging study

Abstract

It is well known that most odorants stimulate the trigeminal system but the time course of the brain regions activated by these chemical stimulations remains poorly documented, especially regarding the trigeminal system. This functional magnetic resonance imaging (fMRI) study compares brain activations resulting from the contrast between two odorant conditions (one bimodal odor and one relatively pure olfactory stimulant) according to the duration of the stimulation (i.e. one inhalation, or three or six successive inhalations). The results show striking differences in the main brain regions activated according to these durations. The caudate nucleus and the orbitofrontal cortex are only involved in short-duration stimulations, and the posterior insular cortex and post-central gyrus (SI) are only activated by long duration stimulations. Different regions of the frontal, temporal and occipital lobe are activated depending on the duration but mainly during medium-duration stimulations. These results expand on the findings of previous studies and contribute to the description of temporal networks in trigeminal perception.

An fMRI study on the influence of sommeliers' expertise on the integration of flavor

“…Slightly different locations of the orbitofrontal cortex may be suspected in the case of strong bitterness such as beer relative to sweet flavors (Small et al, 2007 ). Trigeminal sensations during the test phase can however vary greatly (depending on alcohol content, tannin, astringency, pH…) and therefore recruit more or less the secondary somatosensory cortex S II (Bensafi et al, 2008 ; Billot et al, 2011 ; King et al, 2013 ).…”

Time Course of Perceptual Adaptation Differs among Odorants

“…In contrast, trigeminal components may exhibit a slower onset time course of adaptation relative to olfactory components, even when delivered in very brief bursts (Stone et al 1972). In line with this evidence, qualitative differences between the early processing of trigeminal information and olfactory information have been observed at both the peripheral and central levels of the nervous system (Billot et al 2011).…”

“…In line with this evidence, qualitative differences between the early processing of trigeminal information and olfactory information have been observed at both the peripheral and central levels of the nervous system (Billot et al . ).…”

Cerebral bases of emotion regulation toward odours: A first approach

“…Indeed, it can be supposed that it is just not considered in most of the studies on emotion regulation which focused on the cerebral networks. Cerebellar activations in response to odours have been reported in several imaging studies, with unpleasant or pleasant odorants [26,[49][50][51], and these activations are proportional to odour concentration [52]. As sniff volume is inversely proportional to odour concentration, the hypothesis [29] is the involvement of the cerebellum in a rapid feedback for regulation of the sniff volume, more activated when the sniff volume has to be controlled (decreased in the case of a high concentration).…”