Temporal processing of olfactory stimuli during retronasal perception

Wilkes, Fiona J.; Laing, David G.; Hutchinson, Ian; Jinks, Anthony L; Monteleone, Erminio

doi:10.1016/j.bbr.2008.12.031

Cited by 19 publications

(17 citation statements)

References 23 publications

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“…The adsorptive effects discussed above may be supported by the observation of Wilkes et al (2009) that lower intensity levels of single odorants were perceived by panellists during retronasal evaluation, indicating that adsorption was greater via this route. However, it has also been discussed that based on learnt concepts, differential processing of olfactory stimuli takes place when odorants are presented orthonasally or retronasally, indicating that this might be the reason for differences in ortho and retronasal perception (Heilmann and Hummel, 2004).…”

Section: Interaction Phenomena and Learningmentioning

confidence: 68%

“…General comparisons of ortho and retronasal perception by several groups have revealed that orthonasal perception provides a more efficient route for detection and identification of odorants than the retronasal passage (Halpern, 2004;Heilmann & Hummel, 2004;Sun & Halpern, 2005;Voirol & Daget, 1986;Wilkes, Laing, Hutchinson, Jinks, & Monteleone, 2009). As an example, Heilmann and Hummel reported lower odour thresholds for chocolate and lavender odours when presented orthonasally compared with retronasally.…”

Section: Interaction Phenomena and Learningmentioning

confidence: 96%

“…Accordingly, amplitudes and latencies of olfactory ERPs for retronasal stimuli were found to be smaller. As an explanation for such discrepancies, Wilkes et al (2009) discussed this issue on a purely physiological basis: The authors suggest that there is potentially a greater adsorption of odorants by the nasopharyngeal mucus along the retronasal path compared to the nasal mucus, resulting in a reduction of the total odorant peak concentration or a temporal delay in odorant passage to the receptor site. In this context, the authors postulate that a greater adsorptive area and potentially different composition of the nasopharyngeal mucus might be a key factor in odorant delivery efficiency, although no morphological evidence has been provided for the latter.…”

Section: Interaction Phenomena and Learningmentioning

confidence: 97%

See 2 more Smart Citations

Chemical input – Sensory output: Diverse modes of physiology–flavour interaction

Buettner

Beauchamp

2010

Food Quality and Preference

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Section: Interaction Phenomena and Learningmentioning

confidence: 68%

Section: Interaction Phenomena and Learningmentioning

confidence: 96%

Section: Interaction Phenomena and Learningmentioning

confidence: 97%

See 1 more Smart Citation

Chemical input – Sensory output: Diverse modes of physiology–flavour interaction

Buettner

Beauchamp

2010

Food Quality and Preference

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“…Concentration gradients will be accentuated if stimulus molecules are removed by adsorption to upstream mucosal surfaces while being transported to downstream receptor sites (chromatographic hypothesis) [19,22,55,59]. Previous studies suggested that initial adsorption of odor molecules to non-olfactory regions such as the nasopharynx diminishes the amount of odorant entering the posterior nares and reaching the olfactory epithelium via the retronasal route [6,18,23,60]. Adsorption gradients of odorants are predicted to depend on their physicochemical properties, with steeper gradients generated by stronger mucosal adsorption of more polar compounds [23,53,60].…”

Section: Discussionmentioning

confidence: 99%

Glomerular input patterns in the mouse olfactory bulb evoked by retronasal odor stimuli

2013

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BackgroundOdorant stimuli can access the olfactory epithelium either orthonasally, by inhalation through the external nares, or retronasally by reverse airflow from the oral cavity. There is evidence that odors perceived through these two routes can differ in quality and intensity. We were curious whether such differences might potentially have a neural basis in the peripheral mechanisms of odor coding. To explore this possibility, we compared olfactory receptor input to glomeruli in the dorsal olfactory bulb evoked by orthonasal and retronasal stimulation. Maps of glomerular response were acquired by optical imaging of transgenic mice expressing synaptopHluorin (spH), a fluorescent reporter of presynaptic activity, in olfactory nerve terminals.ResultsWe found that retronasally delivered odorants were able to activate inputs to multiple glomeruli in the dorsal olfactory bulb. The retronasal responses were smaller than orthonasal responses to odorants delivered at comparable concentrations and flow rates, and they displayed higher thresholds and right-shifted dose–response curves. Glomerular maps of orthonasal and retronasal responses were usually well overlapped, with fewer total numbers of glomeruli in retronasal maps. However, maps at threshold could be quite distinct with little overlap. Retronasal responses were also more narrowly tuned to homologous series of aliphatic odorants of varying carbon chain length, with longer chain, more hydrophobic compounds evoking little or no response at comparable vapor levels.ConclusionsSeveral features of retronasal olfaction are possibly referable to the observed properties of glomerular odorant responses. The finding that retronasal responses are weaker and sparser than orthonasal responses is consistent with psychophysical studies showing lower sensitivity for retronasal olfaction in threshold and suprathreshold tests. The similarity and overlap of orthonasal and retronasal odor maps at suprathreshold concentrations agrees with generally similar perceived qualities for the same odorant stimuli administered by the two routes. However, divergence of maps near threshold is a potential factor in perceptual differences between orthonasal and retronasal olfaction. Narrower tuning of retronasal responses suggests that they may be less influenced by chromatographic adsorption effects.

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“…In the nasal mucus odorants are subject to a variety of perireceptor effects by the complex mixture of enzymes, including the OBPs and ODEs, mucopolysaccharides, antibodies, and salts, including metal ions. For example, it has been proposed that the nasopharyngeal mucus “behaves like a polar chromatographic column,” 42a with differential diffusion rates, air/mucus partition coefficients 42b and solubility toward dissolved odorants, 42c which could lead to isotopologue separation. As noted above, the musk isotopologues show significant differences in gas chromatographic retention times.…”

Section: Theories Of Olfactionmentioning

confidence: 99%

The role of metals in mammalian olfaction of low molecular weight organosulfur compounds

et al. 2017

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While suggestions concerning the possible role of metals in olfaction and taste date back 50 years, only recently has it been possible to confirm these proposals with experiments involving individual olfactory receptors (ORs). A detailed discussion of recent experimental results demonstrating the key role of metals in enhancing the response of human and other vertebrate ORs to specific odorants is presented against the backdrop of our knowledge of how the sense of smell functions both at the molecular and whole animal levels. This review emphasizes the role of metals in the detection of low molecular weight thiols, sulfides, and other organosulfur compounds, including those found in strong-smelling animal excretions and plant volatiles, and those used in gas odorization. Alternative theories of olfaction are described, with evidence favoring the modified “shape” theory. The use of quantum mechanical/molecular modeling (QM/MM), site-directed mutagenesis and saturation-transfer-difference (STD) NMR is discussed, providing support for biological studies of mouse and human receptors, MOR244-3 and OR OR2T11, respectively. Copper is bound at the active site of MOR244-3 by cysteine and histidine, while cysteine, histidine and methionine are involved with OR2T11. The binding pockets of these two receptors are found in different locations in the three-dimensional seven transmembrane models. Another recently deorphaned human olfactory receptor, OR2M3, highly selective for a thiol from onions, and a broadly-tuned thiol receptor, OR1A1, are also discussed. Other topics covered include the effects of nanoparticles and heavy metal toxicants on vertebrate and fish ORs, intranasal zinc products and the loss of smell (anosmia).

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Temporal processing of olfactory stimuli during retronasal perception

Cited by 19 publications

References 23 publications

Chemical input – Sensory output: Diverse modes of physiology–flavour interaction

Chemical input – Sensory output: Diverse modes of physiology–flavour interaction

Glomerular input patterns in the mouse olfactory bulb evoked by retronasal odor stimuli

The role of metals in mammalian olfaction of low molecular weight organosulfur compounds

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