Intranasal chemosensory function of the trigeminal nerve and aspects of its relation to olfaction

Abstract

This interaction between the trigeminal and olfactory systems is an important determinant of sensations of odor. Further, it appears to change as a result of aging and disease. Thus, the interaction between the olfactory and trigeminal systems is not straightforward and may be difficult to predict, but it has a powerful influence on the perception of odors.

Understanding the underlying dimensions in perfumers' odor perception space as a basis for developing meaningful odor maps

“…A number of chemical trigeminal stimulants produce effects described as irritating, tingling, pungent, cooling (menthol), or hot (capsaicin). The interaction between the trigeminal and olfactory systems is an important determinant of odor sensations (Hummel & Livermore, 2002).…”

Adverse Effect of Air Pollution on Odor Perception

“…However, one of the most important findings is the relation between the decline in olfactory sensitivity and a reduction of trigeminal sensitivity; there is increasing evidence that an acquired loss of the sense of smell results in a reduction in trigeminal sensitivity due to the lack of interaction centrally (Hummel & Livermore, 2002). Both the orbitofrontal cortex and the rostral insula seem to be important in the amplification of trigeminal information, and this amplification is not found in anosmic patients and is reduced in hyposmic patients .…”

A Novel Device for the Clinical Assessment of Intranasal Trigeminal Sensitivity

“…Each nostril was tested using 3 different concentrations of CO 2 (35%, 45%, 55%; air flow 1 L/min), starting with 2 stimuli of the lowest concentration, resulting in a total of 6 stimuli for each side of the nose. The procedure was repeated with a 10-minute interval, to a total of 4 test measurements (measurements [1][2][3][4]. No adverse effects were reported by any of the participants.…”

“…Trigeminal receptors respond to a wide variety of substances, including capsaicin, menthol, gingerol, piperine, and carbon dioxide (CO 2 ), and these chemicals have been reported to elicit pain perception described as stinging, tingling, pungent, burning, or cooling. 1 Most odorants activate trigeminal as well as olfactory receptors, and an interaction between the trigeminal and the olfactory system has been reported.…”

“…A known stimulus specific to trigeminal receptors is CO 2 , which has been used to assess the antinociceptive effect of various analgesic drugs. 6 However, current clinical assays that assess intranasal trigeminal function are unreliable or time consuming, indicating a need for a practical and effective test that can be integrated easily into standard outpatient care.…”