1
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Kato M, Okamoto M, Kumazaki H. Measurement and Analyses of Olfactory Event-Related Potentials. Methods Mol Biol 2025; 2915:117-129. [PMID: 40249486 DOI: 10.1007/978-1-0716-4466-9_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2025]
Abstract
Olfactory event-related potentials (OERPs) are brain electrical activities time-locked to olfactory stimuli, detectable via scalp electrodes. They offer a noninvasive means to study cortical olfactory processing in humans. Previous research suggests that olfactory cortical processing occurring within several seconds after the onset of an odor can be tracked using OERPs. This enables the investigation of the temporal dynamics of neural activity, spanning from those associated with odor properties to subjects' states. Moreover, OERPs are influenced by diseases, including olfactory, neurological, or psychiatric conditions, and have the potential to serve as biomarkers. This chapter describes the measurement and analysis methods required to obtain OERPs, with a particular focus on odor delivery, aiming to provide a primer for those unfamiliar with OERP measurement.
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Affiliation(s)
- Mugihiko Kato
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Masako Okamoto
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Hirokazu Kumazaki
- Department of Neuropsychiatry, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
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2
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Oleszkiewicz A, Pozzer A, Williams J, Hummel T. Ambient air pollution undermines chemosensory sensitivity - a global perspective. Sci Rep 2024; 14:30462. [PMID: 39681570 DOI: 10.1038/s41598-024-75067-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 10/01/2024] [Indexed: 12/18/2024] Open
Abstract
This study offers insights into the complex relationship between chemical species constituting air pollution and chemosensory function. We examined the relationship between chemical species known to contribute to air pollution and assault human health and chemosensory sensitivity. Chemosensory sensitivity data was retrieved from a large-scale study involving 711 urban-dwelling participants inhabiting 10 different regions of the globe. Their olfactory threshold towards phenyl ethyl alcohol (PEA) and olfactory/trigeminal threshold towards Eucalyptol was measured in a multicentre study. We matched the individual chemosensory data with the levels of PM2.5, PM10, O3, NO2, SO2, CO at the location of testing sites, on the exact date of the test, using EMAC (ECHAM5/MESSy for Atmospheric Chemistry) model. Our findings indicate that air pollution negatively affects olfactory function and has cumulative negative effects with aging. The reported patterns are seasonal and increase during Autumn and Winter, and interact with medical conditions related to poorer olfactory function. We extend the current knowledge by demonstrating that olfactory/trigeminal perception is also disrupted by toxic air, albeit in a slightly different manner. The analyzed models promote a more complex perspective on the relationship between air composition and chemosensory sensitivity, but delineate problems related to the interdependence of the levels of chemical species constituting air pollution and using them together to predict chemosensory sensitivity. Conclusions point to the need to investigate the problem of air pollution and chemosensory health from a global perspective, as air quality partly accounts for the differences in chemosensory perception in different regions of the world.
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Affiliation(s)
- Anna Oleszkiewicz
- Smell and Taste Clinic, TU Dresden, Dresden, Germany.
- Institute of Psychology, University of Wroclaw, ul. Dawida 1, Wroclaw, 50-527, Poland.
| | - Andrea Pozzer
- Max Planck Institute for Chemistry, Mainz, Germany
- Climate and Atmosphere Research Center, The Cyprus Institute, Nicosia, Cyprus
| | - Jonathan Williams
- Max Planck Institute for Chemistry, Mainz, Germany
- Climate and Atmosphere Research Center, The Cyprus Institute, Nicosia, Cyprus
| | - Thomas Hummel
- Smell and Taste Clinic, TU Dresden, Dresden, Germany
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3
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Karunanayaka PR, Lu J, Elyan R, Yang QX, Sathian K. Olfactory-trigeminal integration in the primary olfactory cortex. Hum Brain Mapp 2024; 45:e26772. [PMID: 38962966 PMCID: PMC11222875 DOI: 10.1002/hbm.26772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 06/07/2024] [Accepted: 06/16/2024] [Indexed: 07/05/2024] Open
Abstract
Humans naturally integrate signals from the olfactory and intranasal trigeminal systems. A tight interplay has been demonstrated between these two systems, and yet the neural circuitry mediating olfactory-trigeminal (OT) integration remains poorly understood. Using functional magnetic resonance imaging (fMRI), combined with psychophysics, this study investigated the neural mechanisms underlying OT integration. Fifteen participants with normal olfactory function performed a localization task with air-puff stimuli, phenylethyl alcohol (PEA; rose odor), or a combination thereof while being scanned. The ability to localize PEA to either nostril was at chance. Yet, its presence significantly improved the localization accuracy of weak, but not strong, air-puffs, when both stimuli were delivered concurrently to the same nostril, but not when different nostrils received the two stimuli. This enhancement in localization accuracy, exemplifying the principles of spatial coincidence and inverse effectiveness in multisensory integration, was associated with multisensory integrative activity in the primary olfactory (POC), orbitofrontal (OFC), superior temporal (STC), inferior parietal (IPC) and cingulate cortices, and in the cerebellum. Multisensory enhancement in most of these regions correlated with behavioral multisensory enhancement, as did increases in connectivity between some of these regions. We interpret these findings as indicating that the POC is part of a distributed brain network mediating integration between the olfactory and trigeminal systems. PRACTITIONER POINTS: Psychophysical and neuroimaging study of olfactory-trigeminal (OT) integration. Behavior, cortical activity, and network connectivity show OT integration. OT integration obeys principles of inverse effectiveness and spatial coincidence. Behavioral and neural measures of OT integration are correlated.
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Affiliation(s)
- Prasanna R. Karunanayaka
- Department of RadiologyPennsylvania State University College of MedicineHersheyPennsylvaniaUSA
- Department of Neural and Behavioral SciencesPennsylvania State University College of MedicineHersheyPennsylvaniaUSA
- Department of Public Health SciencesPennsylvania State University College of MedicineHersheyPennsylvaniaUSA
| | - Jiaming Lu
- Department of RadiologyPennsylvania State University College of MedicineHersheyPennsylvaniaUSA
- Drum Tower HospitalMedical School of Nanjing UniversityNanjingChina
| | - Rommy Elyan
- Department of RadiologyPennsylvania State University College of MedicineHersheyPennsylvaniaUSA
| | - Qing X. Yang
- Department of RadiologyPennsylvania State University College of MedicineHersheyPennsylvaniaUSA
- Department of NeurosurgeryPennsylvania State University College of MedicineHersheyPennsylvaniaUSA
| | - K. Sathian
- Department of Neural and Behavioral SciencesPennsylvania State University College of MedicineHersheyPennsylvaniaUSA
- Department of NeurologyPenn State Health Milton S. Hershey Medical CenterHersheyPennsylvaniaUSA
- Department of PsychologyPennsylvania State University College of Liberal ArtsState CollegePennsylvaniaUSA
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4
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Ye Y, Wang Y, Zhuang Y, Tan H, Zuo Z, Yun H, Yuan K, Zhou W. Decomposition of an odorant in olfactory perception and neural representation. Nat Hum Behav 2024; 8:1150-1162. [PMID: 38499771 DOI: 10.1038/s41562-024-01849-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 02/19/2024] [Indexed: 03/20/2024]
Abstract
Molecules-the elementary units of substances-are commonly considered the units of processing in olfactory perception, giving rise to undifferentiated odour objects invariant to environmental variations. By selectively perturbing the processing of chemical substructures with adaptation ('the psychologist's microelectrode') in a series of psychophysical and neuroimaging experiments (458 participants), we show that two perceptually distinct odorants sharing part of their structural features become significantly less discernible following adaptation to a third odorant containing their non-shared structural features, in manners independent of olfactory intensity, valence, quality or general olfactory adaptation. The effect is accompanied by reorganizations of ensemble activity patterns in the posterior piriform cortex that parallel subjective odour quality changes, in addition to substructure-based neural adaptations in the anterior piriform cortex and amygdala. Central representations of odour quality and the perceptual outcome thus embed submolecular structural information and are malleable by recent olfactory encounters.
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Affiliation(s)
- Yuting Ye
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
- Institute of Psychology, School of Public Affairs, Xiamen University, Xiamen, China
| | - Yanqing Wang
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
- School of Psychology, Northwest Normal University, Lanzhou, China
| | - Yuan Zhuang
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Huibang Tan
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Zhentao Zuo
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
- Sino-Dannish College, University of Chinese Academy of Sciences, Beijing, China
| | - Hanqi Yun
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Kaiqi Yuan
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Wen Zhou
- State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.
- Chinese Institute for Brain Research, Beijing, China.
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5
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Lee S, Kim J, Kim BJ, Kim RY, Ha E, Kim S, Hong SN, Lyoo IK, Kim DW. Gray matter volume reduction in the emotional brain networks in adults with anosmia. J Neurosci Res 2022; 100:1321-1330. [PMID: 35240720 DOI: 10.1002/jnr.25037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 01/24/2022] [Accepted: 02/12/2022] [Indexed: 11/10/2022]
Abstract
Loss of olfaction, or anosmia, frequently accompanies emotional dysfunctions, partly due to the overlapping brain regions between the olfactory and emotional processing centers. Here, we investigated whether anosmia was associated with gray matter volume alterations at a network level, and whether these alterations were related to the olfactory-specific quality of life (QOL) and depressive symptoms. Structural brain magnetic resonance imaging was acquired in 22 individuals with postinfectious or idiopathic anosmia (the anosmia group) and 30 age- and sex-matched controls (the control group). Using independent component analysis on the gray matter volumes, we identified 10 morphometric networks. The gray matter volumes of these networks were compared between the two groups. Olfactory-specific QOL and depressive symptoms were assessed by self-report questionnaires and clinician-administered interviews, respectively. The anosmia group showed lower gray matter volumes in the hippocampus-amygdala and the precuneus networks, relative to the control group. Lower gray matter volumes in the hippocampus-amygdala network were also linearly associated with lower olfactory-specific QOL and higher depressive symptom scores. These findings suggest a close relationship between anosmia and gray matter volume alterations in the emotional brain networks, albeit without determined causal relations.
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Affiliation(s)
- Suji Lee
- Ewha Brain Institute, Ewha W. University, Seoul, South Korea
| | - Jungyoon Kim
- Ewha Brain Institute, Ewha W. University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, Ewha W. University, Seoul, South Korea
| | - Bong Jik Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Chungnam National University College of Medicine, Chungnam National University Sejong Hospital, Sejong, South Korea
| | - Rye Young Kim
- Ewha Brain Institute, Ewha W. University, Seoul, South Korea.,Graduate School of Pharmaceutical Sciences, Ewha W. University, Seoul, South Korea
| | - Eunji Ha
- Ewha Brain Institute, Ewha W. University, Seoul, South Korea
| | - Shinhye Kim
- Ewha Brain Institute, Ewha W. University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, Ewha W. University, Seoul, South Korea
| | - Seung-No Hong
- Department of Otorhinolaryngology-Head and Neck Surgery, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, South Korea
| | - In Kyoon Lyoo
- Ewha Brain Institute, Ewha W. University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, Ewha W. University, Seoul, South Korea.,Graduate School of Pharmaceutical Sciences, Ewha W. University, Seoul, South Korea.,The Brain Institute and Department of Psychiatry, University of Utah, Salt Lake City, Utah, USA
| | - Dae Woo Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, South Korea
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6
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Ischer M, Coppin G, De Marles A, Essellier M, Porcherot C, Cayeux I, Margot C, Sander D, Delplanque S. Exogenous capture of visual spatial attention by olfactory-trigeminal stimuli. PLoS One 2021; 16:e0252943. [PMID: 34111171 PMCID: PMC8191882 DOI: 10.1371/journal.pone.0252943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 05/25/2021] [Indexed: 11/18/2022] Open
Abstract
The extent to which a nasal whiff of scent can exogenously orient visual spatial attention remains poorly understood in humans. In a series of seven studies, we investigated the existence of an exogenous capture of visual spatial attention by purely trigeminal (i.e., CO2) and both olfactory and trigeminal stimuli (i.e., eucalyptol). We chose these stimuli because they activate the trigeminal system which can be considered as an alert system and are thus supposedly relevant for the individual, and thus prone to capture attention. We used them as lateralized cues in a variant of a visual spatial cueing paradigm. In valid trials, trigeminal cues and visual targets were presented on the same side whereas in invalid trials they were presented on opposite sides. To characterize the dynamics of the cross-modal attentional capture, we manipulated the interval between the onset of the trigeminal cues and the visual targets (from 580 to 1870 ms). Reaction times in trigeminal valid trials were shorter than all other trials, but only when this interval was around 680 or 1170 ms for CO2 and around 610 ms for eucalyptol. This result reflects that both pure trigeminal and olfactory-trigeminal stimuli can exogenously capture humans’ spatial visual attention. We discuss the importance of considering the dynamics of this cross-modal attentional capture.
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Affiliation(s)
- Matthieu Ischer
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland
- Department of Psychology, University of Geneva, Geneva, Switzerland
| | - Géraldine Coppin
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland
- Department of Psychology, University of Geneva, Geneva, Switzerland
- Swiss Distance University Institute (UniDistance/FernUni), Brig, Switzerland
| | - Axel De Marles
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland
| | - Myriam Essellier
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland
- Department of Psychology, University of Geneva, Geneva, Switzerland
| | | | | | | | - David Sander
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland
- Department of Psychology, University of Geneva, Geneva, Switzerland
| | - Sylvain Delplanque
- Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland
- Department of Psychology, University of Geneva, Geneva, Switzerland
- * E-mail:
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7
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Hucke CI, Heinen RM, Pacharra M, Wascher E, van Thriel C. Spatiotemporal Processing of Bimodal Odor Lateralization in the Brain Using Electroencephalography Microstates and Source Localization. Front Neurosci 2021; 14:620723. [PMID: 33519370 PMCID: PMC7838499 DOI: 10.3389/fnins.2020.620723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/01/2020] [Indexed: 01/01/2023] Open
Abstract
The neuronal cascade related to the perception of either purely olfactory or trigeminal airborne chemicals has been investigated using electroencephalography (EEG) microstate analyses and source localization. However, most airborne chemicals are bimodal in nature, encompassing both properties. Moreover, there is an ongoing debate regarding whether there is one dominant nostril, and this could be investigated using these multichannel EEG methods. In this study, 18 right-handed, healthy participants (13 females) were monorhinally stimulated using an olfactometer with the bimodal component acetic acid during continuous EEG recording. Participants indicated the side of stimulation, the confidence in their decision, and rated the strength of the evoked perception. EEG microstate clustering determined four distinct maps and successive backfitting procedures, and source estimations revealed a network that evolved from visual-spatial processing areas to brain areas related to basic olfactory and trigeminal sensations (e.g., thalamus, cingulate cortex, insula, parahippocampal, and pre-/post-central gyri) and resulted in activation of areas involved in multisensory integration (e.g., frontal-temporal areas). Right-nostril stimulation was associated with faster microstate transition and longer involvement of the superior temporal gyrus, which was previously linked to chemical localization and provides evidence for a potential nostril dominance. The results describe for the first time the processing cascade of bimodal odor perception using microstate analyses and demonstrate its feasibility to further investigate potential nostril dominance.
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Affiliation(s)
- Christine Ida Hucke
- Department of Toxicology, Neurotoxicology and Chemosensation, Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund, Dortmund, Germany
| | - Rebekka Margret Heinen
- Department Neuropsychology, Institute of Cognitive Neuroscience, Ruhr-University Bochum, Bochum, Germany
| | - Marlene Pacharra
- MSH Medical School Hamburg, University of Applied Sciences and Medical University, Hamburg, Germany
| | - Edmund Wascher
- Department of Ergonomics, Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund, Dortmund, Germany
| | - Christoph van Thriel
- Department of Toxicology, Neurotoxicology and Chemosensation, Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund, Dortmund, Germany
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8
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Sinding C, Thibault H, Hummel T, Thomas-Danguin T. Odor-Induced Saltiness Enhancement: Insights Into The Brain Chronometry Of Flavor Perception. Neuroscience 2020; 452:126-137. [PMID: 33197506 DOI: 10.1016/j.neuroscience.2020.10.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/13/2020] [Accepted: 10/26/2020] [Indexed: 10/23/2022]
Abstract
Flavor perception results from the integration of at least odor and taste. Evidence for such integration is that odors can have taste properties (odor-induced taste). Most brain areas involved in flavor perception are high-level areas; however, primary gustatory and olfactory areas also show activations in response to a combination of odor and taste. While the regions involved in flavor perception are now quite well identified, the network's organization is not yet understood. Using a close to real salty soup model with electroencephalography brain recording, we evaluated whether odor-induced saltiness enhancement would result in differences of amplitude and/or latency in late cognitive P3 peak mostly and/or in P1 early sensory peak. Three target solutions were created from the same base of green-pea soup: i) with a "usual" salt concentration (PPS2), ii) with "reduced" salt (PPS1: -50%), and iii) with reduced salt and a "beef stock" odor (PPS1B). Sensory data showed that the beef odor produced saltiness enhancement in PPS1B in comparison to PPS1. As the main EEG result, the late cognitive P3 peak was delayed by 25 ms in the odor-added solution PPS1B compared to PPS1. The odor alone did not explain this peak amplitude and higher latency in the P3 peak. These results support the classical view that high-level integratory areas process odor-taste interactions with potential top-down effects on primary sensory regions.
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Affiliation(s)
- Charlotte Sinding
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, F-21000 Dijon, France.
| | - Henri Thibault
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, F-21000 Dijon, France
| | - Thomas Hummel
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
| | - Thierry Thomas-Danguin
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, F-21000 Dijon, France
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9
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A methodological investigation of a flexible surface MRI coil to obtain functional signals from the human olfactory bulb. J Neurosci Methods 2020; 335:108624. [PMID: 32032715 DOI: 10.1016/j.jneumeth.2020.108624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/21/2020] [Accepted: 02/03/2020] [Indexed: 11/21/2022]
Abstract
BACKGROUND Mammalian olfaction begins with transduction in olfactory receptors, continues with extensive processing in the olfactory bulb, and culminates in cortical representation. Most rodent studies on the functional neuroanatomy of olfaction have concentrated on the olfactory bulb, yet whether this structure is tuned only to basic chemical features of odorants or also to higher-order perceptual features is unclear. NEW METHOD Whereas studies of the human brain can typically uncover involvement of higher-order feature extraction, this has not been possible in the case of the olfactory bulb, inaccessible to fMRI. The present study examined whether a novel method of acquisition using a facial coil could overcome this limitation. RESULTS A series of experiments provided preliminary evidence of odor-driven responses in the human olfactory bulb, and found that these responses differed between individuals. COMPARISON WITH EXISTING METHODS AND CONCLUSIONS The present preliminary technical achievement renders possible to design novel human odor fMRI studies by considering the olfactory system from the olfactory bulb to associative areas.
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10
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Okumura T, Kumazaki H, Singh AK, Touhara K, Okamoto M. Individuals With Autism Spectrum Disorder Show Altered Event-Related Potentials in the Late Stages of Olfactory Processing. Chem Senses 2020; 45:37-44. [PMID: 31711116 DOI: 10.1093/chemse/bjz070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Atypical sensory reactivities are pervasive among people with autism spectrum disorder (ASD). With respect to olfaction, most previous studies have used psychophysical or questionnaire-based methodologies; thus, the neural basis of olfactory processing in ASD remains unclear. This study aimed to determine the stages of olfactory processing that are altered in ASD. Fourteen young adults with high-functioning ASD (mean age, 21 years; 3 females) were compared with 19 age-matched typically developing (TD) controls (mean age, 21 years; 4 females). Olfactory event-related potentials (OERPs) for 2-phenylethyl alcohol-a rose-like odor-were measured with 64 scalp electrodes while participants performed a simple odor detection task. Significant group differences in OERPs were found in 3 time windows 542 ms after the stimulus onset. The cortical source activities in these time windows, estimated using standardized low-resolution brain electromagnetic tomography, were significantly higher in ASD than in TD in and around the posterior cingulate cortex, which is known to play a crucial role in modality-general cognitive processing. Supplemental Bayesian analysis provided substantial evidence for an alteration in the later stages of olfactory processing, whereas conclusive evidence was not provided for the earlier stages. These results suggest that olfactory processing in ASD is altered at least at the later, modality-general processing stage.
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Affiliation(s)
- Toshiki Okumura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Hirokazu Kumazaki
- Department of Preventive Intervention for Psychiatric Disorders, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Archana K Singh
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan.,ERATO Touhara Chemosensory Signal Project, JST, University of Tokyo, Tokyo, Japan
| | - Kazushige Touhara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan.,ERATO Touhara Chemosensory Signal Project, JST, University of Tokyo, Tokyo, Japan.,WPI International Research Center for Neurointelligence, University of Tokyo Institutes for Advanced Study, Tokyo, Japan
| | - Masako Okamoto
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan.,ERATO Touhara Chemosensory Signal Project, JST, University of Tokyo, Tokyo, Japan
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11
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Sirous M, Sinning N, Schneider TR, Friese U, Lorenz J, Engel AK. Chemosensory Event-Related Potentials in Response to Nasal Propylene Glycol Stimulation. Front Hum Neurosci 2019; 13:99. [PMID: 30949040 PMCID: PMC6435593 DOI: 10.3389/fnhum.2019.00099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 03/04/2019] [Indexed: 11/13/2022] Open
Abstract
Propylene glycol, also denoted as 1.2 propanediol (C3H8O2), often serves as a solvent for dilution of olfactory stimuli. It is supposed to serve as a neutral substance and has been used in many behavioral and electrophysiological studies to dilute pure olfactory stimuli. However, the effect of propylene glycol on perception and on neuronal responses has hitherto never been studied. In this study we tested by means of a threshold test, whether a nasal propylene glycol stimulation is recognizable by humans. Participants were able to recognize propylene glycol at a threshold of 42% concentration and reported a slight cooling effect. In addition to the threshold test, we recorded electroencephalography (EEG) during nasal propylene glycol stimulation to study the neuronal processing of the stimulus. We used a flow olfactometer and stimulated 15 volunteers with three different concentrations of propylene glycol (40 trials each) and water as a control condition (40 trials). To evaluate the neuronal response, we analyzed the event-related potentials (ERPs) and power modulations. The task of the volunteers was to identify a change (olfactory, thermal, or tactile) in the continuous air flow generated by the flow olfactometer. The analysis of the ERPs showed that propylene glycol generates a clear P2 component, which was also visible in the frequency domain as an evoked power response in the theta-band. The source analysis of the P2 revealed a widespread involvement of brain regions, including the postcentral gyrus, the insula and adjacent operculum, the thalamus, and the cerebellum. Thus, it is possible that trigeminal stimulation can at least partly account for sensations and brain responses elicited by propylene glycol. Based on these results, we conclude that the use of high propylene glycol concentrations to dilute fragrances complicates the interpretation of presumed purely olfactory effects.
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Affiliation(s)
- Mohammad Sirous
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nico Sinning
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Till R Schneider
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Uwe Friese
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Faculty of Life Science, MSH Medical School Hamburg, Hamburg, Germany
| | - Jürgen Lorenz
- Faculty of Life Science, Laboratory of Human Biology and Physiology, Applied Science University, Hamburg, Germany
| | - Andreas K Engel
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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12
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Singh AK, Touhara K, Okamoto M. Electrophysiological correlates of top-down attentional modulation in olfaction. Sci Rep 2019; 9:4953. [PMID: 30894641 PMCID: PMC6426950 DOI: 10.1038/s41598-019-41319-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 03/05/2019] [Indexed: 11/09/2022] Open
Abstract
The capacity to pay attention is important for the cognitive ability, for example, evaluating an object for its qualities. Attention can selectively prioritize the neural processes that are relevant to a given task. Neuroimaging investigations on human attention are primarily focused on vision to the exclusion of other sensory systems, particularly olfaction. Neural underpinnings of human olfactory attention are still not clearly understood. Here, we combined electroencephalographic measurements of olfactory event related potential with electrical neuroimaging to investigate how the neural responses after inhaling the same odor differ between conditions with varying levels of attention, and, in which brain areas. We examined the neural responses when participants attended to a rose-like odor of phenylethyl alcohol for evaluating its pleasantness versus its passive inhalation. Our results gathered significant evidence for attentional modulation of the olfactory neural response. The most prominent effect was found for the late positive component, P3, of olfactory event related potential within a second from the odor onset. The source reconstruction of this data revealed activations in a distributed network of brain regions predominantly in inferior frontal cortex, insula, and inferior temporal gyrus. These results suggest that the neuronal modulations from attention to olfactory pleasantness may be subserved by this network.
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Affiliation(s)
- Archana K Singh
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan.
- ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo, Japan.
| | - Kazushige Touhara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan
- ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study, Tokyo, Japan
| | - Masako Okamoto
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan.
- ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo, Japan.
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13
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Kleinhans NM, Reilly M, Blake M, Greco G, Sweigert J, Davis GE, Velasquez F, Reitz F, Shusterman D, Dager SR. FMRI correlates of olfactory processing in typically-developing school-aged children. Psychiatry Res Neuroimaging 2019; 283:67-76. [PMID: 30554128 PMCID: PMC6455969 DOI: 10.1016/j.pscychresns.2018.11.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 12/22/2022]
Abstract
Human olfactory processing is understudied relative to other sensory modalities, despite its links to neurodevelopmental and neurodegenerative disorders. To address this limitation, we developed a fast, robust fMRI odor paradigm that is appropriate for all ages and levels of cognitive functioning. To test this approach, thirty-four typically developing children aged 7-12 underwent fMRI during brief, repeated exposure to phenylethyl alcohol, a flower-scented odor. Prior to fMRI scanning, olfactory testing (odor detection and identification) was conducted. During fMRI stimulus presentation, odorant release was synchronized to each participant's inspiratory phase to ensure participants were inhaling during the odorant exposure. Between group differences and correlations between activation and odor detection threshold scores were tested using the FMRIB Software Library. Results demonstrated that our 2-min paradigm significantly activated primary and secondary olfactory regions. In addition, a significant relationship between odor detection threshold and higher activation in the right amygdala and lower activation in the left frontal, insular, occipital, and cerebellar regions was observed, suggesting that this approach is sensitive to individual differences in olfactory processing. These findings demonstrate the feasibility of studying olfactory function in children using brain imaging techniques.
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Affiliation(s)
- Natalia M Kleinhans
- Department of Radiology, University of Washington, Seattle, WA, United States; Integrated Brain Imaging Center, University of Washington, Seattle, WA, United States; Center on Human Development and Disability, University of Washington, Seattle, WA, United States.
| | - Melissa Reilly
- Department of Radiology, University of Washington, Seattle, WA, United States
| | - Matthew Blake
- Department of Radiology, University of Washington, Seattle, WA, United States
| | - Gabriella Greco
- Department of Radiology, University of Washington, Seattle, WA, United States
| | - Julia Sweigert
- Department of Radiology, University of Washington, Seattle, WA, United States
| | - Greg E Davis
- Department of Otolaryngology, University of Washington, Seattle, WA, United States
| | - Francisco Velasquez
- Department of Radiology, University of Washington, Seattle, WA, United States
| | - Fredrick Reitz
- Center on Human Development and Disability, University of Washington, Seattle, WA, United States
| | - Dennis Shusterman
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Stephen R Dager
- Department of Radiology, University of Washington, Seattle, WA, United States; Center on Human Development and Disability, University of Washington, Seattle, WA, United States; Department of Biomedical Engineering, University of Washington, Seattle, WA, United States
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14
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Abstract
Many odors activate the intranasal chemosensory trigeminal system where they produce cooling and other somatic sensations such as tingling, burning, or stinging. Specific trigeminal receptors are involved in the mediation of these sensations. Importantly, the trigeminal system also mediates sensitivity to airflow. The intranasal trigeminal and the olfactory system are closely connected. With regard to central nervous processing, it is most interesting that trigeminal stimuli can activate the piriform cortex, which is typically viewed as the primary olfactory cortex. This suggests that interactions between the two systems may form at a relatively early stage of processing. For example, there is evidence showing that acquired olfactory loss leads to reduced trigeminal sensitivity, probably on account of the lack of interaction in the central nervous system. Decreased trigeminal sensitivity may also be responsible for changes in airflow perception, leading to the impression of congested nasal airways.
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Affiliation(s)
- Thomas Hummel
- Department of Otorhinolaryngology, Smell and Taste Clinic, Technische Universität Dresden, Dresden, Germany.
| | - Johannes Frasnelli
- Université du Québec à Trois-Rivières, Department of Anatomy, Trois-Rivières, QC, Canada
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15
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Temporal Encoding During Unimodal and Bimodal Odor Processing in the Human Brain. CHEMOSENS PERCEPT 2018. [DOI: 10.1007/s12078-018-9251-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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16
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von Wegner F, Laufs H. Information-Theoretical Analysis of EEG Microstate Sequences in Python. Front Neuroinform 2018; 12:30. [PMID: 29910723 PMCID: PMC5992993 DOI: 10.3389/fninf.2018.00030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/11/2018] [Indexed: 11/13/2022] Open
Abstract
We present an open-source Python package to compute information-theoretical quantities for electroencephalographic data. Electroencephalography (EEG) measures the electrical potential generated by the cerebral cortex and the set of spatial patterns projected by the brain's electrical potential on the scalp surface can be clustered into a set of representative maps called EEG microstates. Microstate time series are obtained by competitively fitting the microstate maps back into the EEG data set, i.e., by substituting the EEG data at a given time with the label of the microstate that has the highest similarity with the actual EEG topography. As microstate sequences consist of non-metric random variables, e.g., the letters A-D, we recently introduced information-theoretical measures to quantify these time series. In wakeful resting state EEG recordings, we found new characteristics of microstate sequences such as periodicities related to EEG frequency bands. The algorithms used are here provided as an open-source package and their use is explained in a tutorial style. The package is self-contained and the programming style is procedural, focusing on code intelligibility and easy portability. Using a sample EEG file, we demonstrate how to perform EEG microstate segmentation using the modified K-means approach, and how to compute and visualize the recently introduced information-theoretical tests and quantities. The time-lagged mutual information function is derived as a discrete symbolic alternative to the autocorrelation function for metric time series and confidence intervals are computed from Markov chain surrogate data. The software package provides an open-source extension to the existing implementations of the microstate transform and is specifically designed to analyze resting state EEG recordings.
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Affiliation(s)
- Frederic von Wegner
- Epilepsy Center Rhein-Main, Goethe University Frankfurt, Frankfurt am Main, Germany.,Department of Neurology and Brain Imaging Center, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Helmut Laufs
- Department of Neurology and Brain Imaging Center, Goethe University Frankfurt, Frankfurt am Main, Germany.,Department of Neurology, University Hospital Kiel, Kiel, Germany
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17
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Pellegrino R, Sinding C, de Wijk RA, Hummel T. Habituation and adaptation to odors in humans. Physiol Behav 2017; 177:13-19. [PMID: 28408237 DOI: 10.1016/j.physbeh.2017.04.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 03/28/2017] [Accepted: 04/08/2017] [Indexed: 10/19/2022]
Abstract
Habituation, or decreased behavioral response, to odors is created by repeated exposure and several detailed characteristics, whereas adaptation relates to the neural processes that constitute this decrease in a behavioral response. As with all senses, the olfactory system continually encounters an enormous variety of odorants which is why mechanisms must exist to segment them and respond to changes. Although most olfactory habitation studies have focused on animal models, this non-systematic review provides an overview of olfactory habituation and adaptation in humans, and techniques that have been used to measure them. Thus far, psychophysics in combination with modern techniques of neural measurement indicate that habituation to odors, or decrease of intensity, is relatively fast with adaptation occurring more quickly at higher cerebral processes than peripheral adaptation. Similarly, it has been demonstrated that many of the characteristics of habitation apply to human olfaction; yet, evidence for some characteristics such as potentiation of habituation or habituation of dishabituation need more support. Additionally, standard experimental designs should be used to minimize variance across studies, and more research is needed to define peripheral-cerebral feedback loops involved in decreased responsiveness to environmental stimuli.
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Affiliation(s)
- R Pellegrino
- Interdisciplinary Center on Smell & Taste, Department of Otorhinolaryngology, TU Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
| | - C Sinding
- Interdisciplinary Center on Smell & Taste, Department of Otorhinolaryngology, TU Dresden, Fetscherstrasse 74, 01307 Dresden, Germany; Centre des Sciences du Goût et de l'Alimentation, CNRS, UMR 6265, INRA, UMR 1324, Université de Bourgogne, Dijon, France
| | - R A de Wijk
- Wageningen Food & Biobased Research, Wageningen, The Netherlands
| | - T Hummel
- Interdisciplinary Center on Smell & Taste, Department of Otorhinolaryngology, TU Dresden, Fetscherstrasse 74, 01307 Dresden, Germany.
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18
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Pérez de Los Cobos Pallares F, Bautista TG, Stanić D, Egger V, Dutschmann M. Brainstem-mediated sniffing and respiratory modulation during odor stimulation. Respir Physiol Neurobiol 2016; 233:17-24. [PMID: 27473930 DOI: 10.1016/j.resp.2016.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/19/2016] [Accepted: 07/26/2016] [Indexed: 11/19/2022]
Abstract
The trigeminal and olfactory systems interact during sensory processing of odor. Here, we investigate odor-evoked modulations of brainstem respiratory networks in a decerebrated perfused brainstem preparation of rat with intact olfactory bulbs. Intranasal application of non-trigeminal odors (rose) did not evoke respiratory modulation in absence of cortico-limbic circuits. Conversely, trigeminal odors such as menthol or lavender evoked robust respiratory modulations via direct activation of preserved brainstem circuits. Trigeminal odors consistently triggered short phrenic nerve bursts (fictive sniff), and the strong trigeminal odor menthol also triggered a slowing of phrenic nerve frequency. Phrenic and vagal nerve recordings reveal that fictive sniffs transiently interrupted odor evoked tonic postinspiratory vagal discharge. This motor pattern is significantly different from normal (eupneic) respiratory activity. In conclusion, we show for the first time the direct involvement of brainstem circuits in primary odor processing to evoke protective sniffs and respiratory modulation in the complete absence of forebrain commands.
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Affiliation(s)
| | - Tara G Bautista
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Gate 11 Royal Parade, Victoria 3052, Australia
| | - Davor Stanić
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Gate 11 Royal Parade, Victoria 3052, Australia
| | - Veronica Egger
- Zoological Institute, University of Regensburg, D-93040 Regensburg, Germany
| | - Mathias Dutschmann
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Gate 11 Royal Parade, Victoria 3052, Australia.
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19
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Differences in the central-nervous processing of olfactory stimuli according to their hedonic and arousal characteristics. Neuroscience 2016; 324:62-8. [DOI: 10.1016/j.neuroscience.2016.03.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 12/18/2022]
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20
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Effects of chronic peripheral olfactory loss on functional brain networks. Neuroscience 2015; 310:589-99. [DOI: 10.1016/j.neuroscience.2015.09.045] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 09/16/2015] [Accepted: 09/18/2015] [Indexed: 01/18/2023]
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21
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Krbot Skorić M, Adamec I, Jerbić AB, Gabelić T, Hajnšek S, Habek M. Electroencephalographic Response to Different Odors in Healthy Individuals: A Promising Tool for Objective Assessment of Olfactory Disorders. Clin EEG Neurosci 2015; 46:370-6. [PMID: 25406126 DOI: 10.1177/1550059414545649] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 07/09/2014] [Indexed: 11/17/2022]
Abstract
The aim of the present study was to examine human central nervous system response to three different odors. Electrophysiological activity was recorded in the baseline state and for 3 odors, lemon, peppermint, and vanilla, in 16 healthy participants. Electrodes were separated into groups according to the spatial position on the head. Fast Fourier transformation was performed on every set, and mean value of activity in theta was exported. As theta showed statistically significant results, further analysis was based only on the theta frequency band. On electrodes FP1, F3, Fz, F4, F8, T7, C3, Cz, C4, T8, TP9, CP5, CP1, CP2, CP6, P7, P3, Pz, P4, P8, PO9, and PO10 there was statistically significant difference in the electrical activity of the brain between four conditions. For peppermint and lemon, there was statistically significant difference in activity between different regions-F(1.576, 23.637)=16.030, P=.000 and F(1.362, 20.425)=4.54, P=.035, respectively-where the activity in the central area was significantly reduced compared with the activity in the other 4 areas and in the left and right anterior and left posterior area, respectively. There was no statistically significant difference for vanilla between specific areas, F(1.217, 18.257)=1.155, P=.309. The results indicate that olfactory stimuli can affect the frequency characteristics of the electrical activity of the brain.
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Affiliation(s)
| | - Ivan Adamec
- Department of Neurology, University Hospital Center Zagreb, Zagreb, Croatia
| | | | - Tereza Gabelić
- Department of Neurology, University Hospital Center Zagreb, Zagreb, Croatia
| | - Sanja Hajnšek
- Department of Neurology, University Hospital Center Zagreb, Zagreb, Croatia School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Mario Habek
- Department of Neurology, University Hospital Center Zagreb, Zagreb, Croatia School of Medicine, University of Zagreb, Zagreb, Croatia
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22
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Iannilli E, Sorokowska A, Zhigang Z, Hähner A, Warr J, Hummel T. Source localization of event-related brain activity elicited by food and nonfood odors. Neuroscience 2015; 289:99-105. [DOI: 10.1016/j.neuroscience.2014.12.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/22/2014] [Accepted: 12/27/2014] [Indexed: 01/25/2023]
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23
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Flohr ELR, Boesveldt S, Haehner A, Iannilli E, Sinding C, Hummel T. Time-course of trigeminal versus olfactory stimulation: evidence from chemosensory evoked potentials. Int J Psychophysiol 2015; 95:388-94. [PMID: 25697131 DOI: 10.1016/j.ijpsycho.2015.01.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 12/19/2014] [Accepted: 01/26/2015] [Indexed: 10/24/2022]
Abstract
Habituation of responses to chemosensory signals has been explored in many ways. Strong habituation and adaptation processes can be observed at the various levels of processing. For example, with repeated exposure, amplitudes of chemosensory event-related potentials (ERP) decrease over time. However, long-term habituation has not been investigated so far and investigations of differences in habituation between trigeminal and olfactory ERPs are very rare. The present study investigated habituation over a period of approximately 80 min for two olfactory and one trigeminal stimulus, respectively. Habituation was examined analyzing the N1 and P2 amplitudes and latencies of chemosensory ERPs and intensity ratings. It was shown that amplitudes of both components - and intensity ratings - decreased from the first to the last block. Concerning ERP latencies no effects of habituation were seen. Amplitudes of trigeminal ERPs diminished faster than amplitudes of olfactory ERPs, indicating that the habituation of trigeminal ERPs is stronger than habituation of olfactory ERPs. Amplitudes of trigeminal ERPs were generally higher than amplitudes of olfactory ERPs, as it has been shown in various studies before. The results reflect relatively selective central changes in response to chemosensory stimuli over time.
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Affiliation(s)
- Elena L R Flohr
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Germany; Department of Psychology (Biological Psychology, Clinical Psychology, and Psychotherapy), University of Würzburg, Germany.
| | - Sanne Boesveldt
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Germany; Division of Human Nutrition, Wageningen University, Wageningen, the Netherlands; Department of Neurology, VU University Medical Center, Amsterdam, the Netherlands
| | - Antje Haehner
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Germany
| | - Emilia Iannilli
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Germany
| | - Charlotte Sinding
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Germany
| | - Thomas Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Germany
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24
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Olfactory short-term memory encoding and maintenance — An event-related potential study. Neuroimage 2014; 98:475-86. [DOI: 10.1016/j.neuroimage.2014.04.083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 03/21/2014] [Accepted: 04/30/2014] [Indexed: 11/17/2022] Open
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25
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Croy I, Schulz M, Blumrich A, Hummel C, Gerber J, Hummel T. Human olfactory lateralization requires trigeminal activation. Neuroimage 2014; 98:289-95. [PMID: 24825502 DOI: 10.1016/j.neuroimage.2014.05.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 05/04/2014] [Indexed: 10/25/2022] Open
Abstract
Rats are able to lateralize odors. This ability involves specialized neurons in the orbitofrontal cortex which are able to process the left, right and bilateral presentation of stimuli. However, it is not clear whether this function is preserved in humans. Humans are in general not able to differentiate whether a selective olfactory stimulant has been applied to the left or right nostril; however exceptions have been reported. Following a screening of 152 individuals with an olfactory lateralization test, we identified 19 who could lateralize odors above chance level. 15 of these "lateralizers" underwent olfactory fMRI scanning in a block design and were compared to 15 controls matched for age and sex distribution. As a result, both groups showed comparable activation of olfactory eloquent brain areas. However, subjects with lateralization ability had a significantly enhanced activation of cerebral trigeminal processing areas (somatosensory cortex, intraparietal sulcus). In contrast to controls, lateralizers furthermore exhibited no suppression in the area of the trigeminal principal sensory nucleus. An exploratory study with an olfactory change detection paradigm furthermore showed that lateralizers oriented faster towards changes in the olfactory environment. Taken together, our study suggests that the trigeminal system is activated to a higher degree by the odorous stimuli in the group of "lateralizers". We conclude that humans are not able to lateralize odors based on the olfactory input alone, but vary in the degree to which the trigeminal system is recruited.
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Affiliation(s)
- Ilona Croy
- University of Dresden Medical School, Smell & Taste Clinic, Dept. of Otorhinolaryngology, Fetscherstr. 74, 01307 Dresden, Germany; University of Gothenburg, Institute of Neuroscience and Physiology, Sahlgrenska University Hospital, Blå Stråket 5, 413 45 Gothenburg, Sweden.
| | - Max Schulz
- University of Dresden Medical School, Smell & Taste Clinic, Dept. of Otorhinolaryngology, Fetscherstr. 74, 01307 Dresden, Germany
| | - Anna Blumrich
- University of Dresden Medical School, Smell & Taste Clinic, Dept. of Otorhinolaryngology, Fetscherstr. 74, 01307 Dresden, Germany
| | - Cornelia Hummel
- University of Dresden Medical School, Smell & Taste Clinic, Dept. of Otorhinolaryngology, Fetscherstr. 74, 01307 Dresden, Germany
| | - Johannes Gerber
- University of Dresden Medical School, Department of Neuroradiology, Fetscherstr. 74, 01307 Dresden, Germany
| | - Thomas Hummel
- University of Dresden Medical School, Smell & Taste Clinic, Dept. of Otorhinolaryngology, Fetscherstr. 74, 01307 Dresden, Germany
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26
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Gastl M, Brünner YF, Wiesmann M, Freiherr J. Depicting the inner and outer nose: the representation of the nose and the nasal mucosa on the human primary somatosensory cortex (SI). Hum Brain Mapp 2014; 35:4751-66. [PMID: 24659451 DOI: 10.1002/hbm.22509] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 02/01/2014] [Accepted: 03/05/2014] [Indexed: 11/08/2022] Open
Abstract
The nose is important not only for breathing, filtering air, and perceiving olfactory stimuli. Although the face and hands have been mapped, the representation of the internal and external surface of the nose on the primary somatosensory cortex (SI) is still poorly understood. To fill this gap functional magnetic resonance imaging (fMRI) was used to localize the nose and the nasal mucosa in the Brodman areas (BAs) 3b, 1, and 2 of the human postcentral gyrus (PG). Tactile stimulation during fMRI was applied via a customized pneumatically driven device to six stimulation sites: the alar wing of the nose, the lateral nasal mucosa, and the hand (serving as a reference area) on the left and right side of the body. Individual representations could be discriminated for the left and right hand, for the left nasal mucosa and left alar wing of the nose in BA 3b and BA 1 by comparing mean activation maxima and Euclidean distances. Right-sided nasal conditions and conditions in BA 2 could further be separated by different Euclidean distances. Regarding the alar wing of the nose, the results concurred with the classic sensory homunculus proposed by Penfield and colleagues. The nasal mucosa was not only determined an individual and bilateral representation, its position on the somatosensory cortex is also situated closer to the caudal end of the PG compared to that of the alar wing of the nose and the hand. As SI is commonly activated during the perception of odors, these findings underscore the importance of the knowledge of the representation of the nasal mucosa on the primary somatosensory cortex, especially for interpretation of results of functional imaging studies about the sense of smell.
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Affiliation(s)
- Mareike Gastl
- Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
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27
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Ohla K, Lundström JN. Sex differences in chemosensation: sensory or emotional? Front Hum Neurosci 2013; 7:607. [PMID: 24133429 PMCID: PMC3783851 DOI: 10.3389/fnhum.2013.00607] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 09/06/2013] [Indexed: 11/16/2022] Open
Abstract
Although the first sex-dependent differences in chemosensory processing were reported in the scientific literature over 60 years ago, the underlying mechanisms are still unknown. Generally, more pronounced sex-dependent differences are noted with increased task difficulty or with increased levels of intranasal irritation produced by the stimulus. Whether differences between the sexes arise from differences in chemosensory sensitivity of the two intranasal sensory systems involved or from differences in cognitive processing associated with emotional evaluation of the stimulants is still not known. We used simultaneous and complementary measures of electrophysiological (EEG), psychophysiological, and psychological responses to stimuli varying in intranasal irritation and odorousness to investigate whether sex differences in the processing of intranasal irritation are mediated by varying sensitivity of the involved sensory systems or by differences in cognitive and/or emotional evaluation of the irritants. Women perceived all stimulants more irritating and they exhibited larger amplitudes of the late positive deflection of the event-related potential than men. No significant differences in sensory sensitivity, anxiety, and arousal responses could be detected. Our findings suggest that men and women process intranasal irritation differently. Importantly, the differences cannot be explained by variation in sensory sensitivity to irritants, differences in anxiety, or differences in physiological arousal. We propose that women allocate more attention to potentially noxious stimuli than men do, which eventually causes differences in cognitive appraisal and subjective perception.
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Affiliation(s)
- Kathrin Ohla
- Monell Chemical Senses Center Philadelphia, PA, USA
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