Preservation of olfaction in surgery of olfactory groove meningiomas.

PubMed

Jang, Woo-Youl; Jung, Shin; Jung, Tae-Young; Moon, Kyung-Sub; Kim, In-Young

2013-08-01

Olfaction is commonly considered as secondary among the sensory functions, perhaps reflecting a lack of interest in sparing olfaction after surgery for the olfactory groove meningiomas (OGM). However, considering the repercussions of olfaction for the quality of life, the assessment of post-operative olfaction should be necessary. We retrospectively reviewed the olfactory outcome in patients with OGM and investigated the factors associated with sparing the post-operative olfaction. Between 1993 and 2012, 40 patients with OGM underwent surgical resection and estimated the olfactory function using the Korean version of "Sniffin'Sticks" test (KVSS). Variable factors, such as tumor size, degree of preoperative edema, tumor consistency, preoperative olfactory function, surgical approaches, patient's age, and gender were analyzed with attention to the post-operative olfactory function. Anatomical and functional preservation of olfactory structures were achieved in 26 patients (65%) and 22 patients (55%), respectively. Among the variable factors, size of tumor was significant related to the preservation of post-operative olfaction. (78.6% in size<4 cm and 42.3% in size>4 cm, p=0.035). Sparing the olfaction was significantly better in patients without preoperative olfactory dysfunction (84.6%) compared with ones with preoperative olfactory dysfunction (40.7%, p=0.016). The frontolateral approach achieved much more excellent post-operative olfactory function (71.4%) than the bifrontal approach (36.8%, p=0.032). If the tumor was smaller than 4 cm and the patients did not present olfactory dysfunction preoperatively, the possibility of sparing the post-operative olfaction was high. Among the variable surgical approaches, frontolateral route may be preferable sparing the post-operative olfaction. Copyright © 2012 Elsevier B.V. All rights reserved.

Presence of neuropathic pain may explain poor performances on olfactory testing in diabetes mellitus patients.

PubMed

Brady, Shauna; Lalli, Paul; Midha, Nisha; Chan, Ayechen; Garven, Alexandra; Chan, Cynthia; Toth, Cory

2013-07-01

Olfactory dysfunction in neurodegenerative conditions such as Parkinson's syndrome and Alzheimer's disease can hallmark disease onset. We hypothesized that patients with diabetes mellitus, a condition featuring peripheral and central neurodegeneration, would have decreased olfaction abilities. We examined participants with diabetic peripheral neuropathy, participants with diabetes without diabetic peripheral neuropathy, and control participants in blinded fashion using standardized Sniffin' Sticks. Diabetic peripheral neuropathy severity was quantified using the Utah Early Neuropathy Scale. Further subcategorization of diabetic peripheral neuropathy based on presence of neuropathic pain was performed with Douleur Neuropathique 4 Questionnaires. Participants with diabetes had decreased olfactory sensitivity, impaired olfactory discrimination abilities, and reduced odor identification skills when compared with controls. However, loss of olfaction ability was, at least partially, attributed to presence of neuropathic pain on subcategory assessment, although pain severity was not associated with dysfunction. Those participants with diabetes without diabetic peripheral neuropathy and those with diabetic peripheral neuropathy without neuropathic pain had similar olfactory function as controls in general. The presence of neuropathic pain, associated with limited attention and concentration, may explain at least a portion of the olfactory dysfunction witnessed in the diabetic patient population.

Anosmia: Differential diagnosis, evaluation, and management.

PubMed

Scangas, George A; Bleier, Benjamin S

2017-01-01

The ability to scrutinize our surroundings remains heavily dependent on the sense of smell. From the ability to detect dangerous situations such as fires to the recollection of a fond memory triggered by an odor, the advantages of an intact olfactory system cannot be overstated. Outcomes studies have highlighted the profound negative impact of anosmia and parosmia on the overall quality of life. The National Institute on Deafness and Other Communication Disorders estimates that ∼1.4% of the United States population experiences chronic olfactory dysfunction and smell loss. Efforts have focused on improving both the diagnosis of olfactory dysfunction through olfactory testing and improved reporting of treatment outcomes of olfactory training. The purpose of this article was to review the differential diagnosis, workup, and current treatment strategies of anosmia and smell disorders.

Ethmoid Histopathology Does Not Predict Olfactory Outcomes after Endoscopic Sinus Surgery

PubMed Central

Soler, Zachary M.; Sauer, David A.; Mace, Jess C.; Smith, Timothy L.

2010-01-01

BACKGROUND Histologic inflammation correlates with the degree of baseline olfactory dysfunction in patients with chronic rhinosinusitis (CRS), however factors associated with improvement in olfactory status after endoscopic sinus surgery (ESS) remain elusive. OBJECTIVE Our purpose was to compare histopathologic findings in CRS patients with olfactory loss and evaluate whether inflammatory markers can predict long-term olfactory improvement after ESS. METHODS Adult (≥18 years) patients with CRS were prospectively enrolled after electing ESS due to failed medical management. Mucosal tissue specimens were collected at the time of surgery and underwent pathlogic review in a blinded fashion. Subjects completed the 40-item Smell Identification Test (SIT) preoperatively and at least 6 months postoperatively. Multivariate logistic regression was used to identify histologic factors associated with postoperative improvement in SIT score. RESULTS The final cohort was comprised of 101 patients with a mean follow-up of 16.7 ± 6.0 months. Mean mucosal eosinophil count was higher in patients with hyposmia and anosmia (p<0.001). Patients with preoperative anosmia were more likely to have greater severity of BM thickening compared to subjects with hyposmia or normosmia (p=0.021). In patients with olfactory dysfunction, 54.7% reported olfactory improvement of at least 4 points on postoperative SIT scores. After controlling for nasal polyposis, histologic variables were not associated with postoperative improvement in olfaction. CONCLUSIONS Patients with severe olfactory dysfunction were more likely to have mucosal eosinophilia and basement membrane thickening on ethmoid histopathologic examination compared to normosmics. The presence of specific histologic inflammatory findings did not however predict olfactory improvement after surgery. PMID:20819467

Proteomic Analysis of the Human Olfactory Bulb.

PubMed

Dammalli, Manjunath; Dey, Gourav; Madugundu, Anil K; Kumar, Manish; Rodrigues, Benvil; Gowda, Harsha; Siddaiah, Bychapur Gowrishankar; Mahadevan, Anita; Shankar, Susarla Krishna; Prasad, Thottethodi Subrahmanya Keshava

2017-08-01

The importance of olfaction to human health and disease is often underappreciated. Olfactory dysfunction has been reported in association with a host of common complex diseases, including neurological diseases such as Alzheimer's disease and Parkinson's disease. For health, olfaction or the sense of smell is also important for most mammals, for optimal engagement with their environment. Indeed, animals have developed sophisticated olfactory systems to detect and interpret the rich information presented to them to assist in day-to-day activities such as locating food sources, differentiating food from poisons, identifying mates, promoting reproduction, avoiding predators, and averting death. In this context, the olfactory bulb is a vital component of the olfactory system receiving sensory information from the axons of the olfactory receptor neurons located in the nasal cavity and the first place that processes the olfactory information. We report in this study original observations on the human olfactory bulb proteome in healthy subjects, using a high-resolution mass spectrometry-based proteomic approach. We identified 7750 nonredundant proteins from human olfactory bulbs. Bioinformatics analysis of these proteins showed their involvement in biological processes associated with signal transduction, metabolism, transport, and olfaction. These new observations provide a crucial baseline molecular profile of the human olfactory bulb proteome, and should assist the future discovery of biomarker proteins and novel diagnostics associated with diseases characterized by olfactory dysfunction.

Long term serious olfactory loss in colds and/or flu.

PubMed

de Haro-Licer, Josep; Roura-Moreno, Jordi; Vizitiu, Anabella; González-Fernández, Adela; González-Ares, Josep Antón

2013-01-01

In the general population, we can find 2-3% of lifelong olfactory disorders (from hyposmia to anosmia). Two of the most frequent aetiologies are the common cold and flu. The aim of this study was to show the degree of long-term olfactory dysfunction caused by a cold or flu. This study was based on 240 patients, with olfactory loss caused only by flu or a cold. We excluded all patients with concomitant illness (66 patients), the rest of patients (n=174) consisted of 51 men (29.3%) and 123 women (70.7%). They all underwent olfactometry study (i and v cranial nerve) and a nasal sinus computed tomography scan, as well as magnetic resonance imaging of the brain. Results were compared with a control group (n=120). Very significant differences in levels of olfactory impairment for the olfactory nerve (P<.00001) and trigeminal nerve (P<.0001) were confirmed. People that suffer olfactory dysfunction for more than 6 months, from flu or a cold, present serious impairment of olfactory abilities. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Olfaction in Parkinson's disease and related disorders

PubMed Central

Doty, Richard L.

2012-01-01

Olfactory dysfunction is an early ‘pre-clinical’ sign of Parkinson's disease (PD). The present review is a comprehensive and up-to-date assessment of such dysfunction in PD and related disorders. The olfactory bulb is implicated in the dysfunction, since only those syndromes with olfactory bulb pathology exhibit significant smell loss. The role of dopamine in the production of olfactory system pathology is enigmatic, as overexpression of dopaminergic cells within the bulb's glomerular layer is a common feature of PD and most animal models of PD. Damage to cholinergic, serotonergic, and noradrenergic systems is likely involved, since such damage is most marked in those diseases with the most smell loss. When compromised, these systems, which regulate microglial activity, can influence the induction of localized brain inflammation, oxidative damage, and cytosolic disruption of cellular processes. In monogenetic forms of PD, olfactory dysfunction is rarely observed in asymptomatic gene carriers, but is present in many of those that exhibit the motor phenotype. This suggests that such gene-related influences on olfaction, when present, take time to develop and depend upon additional factors, such as those from aging, other genes, formation of α-synuclein- and tau-related pathology,or lowered thresholds to oxidative stress from toxic insults. The limited data available suggest that the physiological determinants of the early changes in PD-related olfactory function are likely multifactorial and may include the same determinants as those responsible for a number of other non-motor symptoms of PD, such as dysautonomia and sleep disturbances. PMID:22192366

Validation of a new scale to assess olfactory dysfunction in patients with Parkinson's disease.

PubMed

Millar Vernetti, Patricio; Perez Lloret, Santiago; Rossi, Malco; Cerquetti, Daniel; Merello, Marcelo

2012-05-01

BAKCKGROUND: Olfactory dysfunction is present in up to 90% of Parkinson's disease (PD) patients. It is usually evaluated by means of objective standardized tests; however no self-administered scales have been developed for olfactory dysfunction bedside assessment. We present validation of a new scale to assess this symptom in PD patients. Seventy-five PD patients and 25 control subjects were evaluated using a Hyposmia Rating Scale developed in-house, combined with the extended Sniffin' Sticks test. Total score of the 6-item Hyposmia Rating Scale showed significant correlation with threshold, discrimination, identification and total Sniffin' Sticks test scores (r = 0.53; r = 0.60; r = 0.57; r = 0.65 respectively, p < 0.001 for all values). Area under the curve of the receiver operating curve for the ability of Hyposmia Rating Scale to discriminate patients with Sniffin' Sticks test total scores below or above the cut-off point was 80 ± 6% (p < 0.001). Considering Sniffin' Sticks test as the gold standard method for olfactory dysfunction detection, an affirmative response to a single screening question about smelling ability problems showed 35% sensitivity (95%CI = 23-47%) and 100% specificity. The best cut-off point for Hyposmia Rating Scale was 22.5 with a sensitivity of 70% (60-81%) and a specificity of 85% (65-100%). The Hyposmia Rating Scale here presented may offer a simple, cost-effective, time-saving and reliable approach to evaluate olfactory dysfunction in PD patients. Copyright © 2011. Published by Elsevier Ltd.

Effects of Ambient Air Pollution Exposure on Olfaction: A Review.

PubMed

Ajmani, Gaurav S; Suh, Helen H; Pinto, Jayant M

2016-11-01

Olfactory dysfunction affects millions of people worldwide. This sensory impairment is associated with neurodegenerative disease and significantly decreased quality of life. Exposure to airborne pollutants has been implicated in olfactory decline, likely due to the anatomic susceptibility of the olfactory nerve to the environment. Historically, studies have focused on occupational exposures, but more recent studies have considered effects from exposure to ambient air pollutants. To examine all relevant human data evaluating a link between ambient pollution exposure and olfaction and to review supporting animal data in order to examine potential mechanisms for pollution-associated olfactory loss. We identified and reviewed relevant articles from 1950 to 2015 using PubMed and Web of Science and focusing on human epidemiologic and pathophysiologic studies. Animal studies were included only to support pertinent data on humans. We reviewed findings from these studies evaluating a relationship between environmental pollutant exposure and olfactory function. We identified and reviewed 17 articles, with 1 additional article added from a bibliography search, for a total of 18 human studies. There is evidence in human epidemiologic and pathologic studies that increased exposure to ambient air pollutants is associated with olfactory dysfunction. However, most studies have used proxies for pollution exposure in small samples of convenience. Human pathologic studies, with supporting animal work, have also shown that air pollution can contact the olfactory epithelium, translocate to the olfactory bulb, and migrate to the olfactory cortex. Pollutants can deposit at each location, causing direct damage and disruption of tissue morphology or inducing local inflammation and cellular stress responses. Ambient air pollution may impact human olfactory function. Additional studies are needed to examine air pollution-related olfactory impacts on the general population using measured pollution exposures and to link pollution exposure with olfactory dysfunction and related pathology. Citation: Ajmani GS, Suh HH, Pinto JM. 2016. Effects of ambient air pollution exposure on olfaction: a review. Environ Health Perspect 124:1683-1693; http://dx.doi.org/10.1289/EHP136.

Sensitivity and Specificity of Self-Reported Olfactory Function in a Home-Based Study of Independent-Living, Healthy Older Women

PubMed Central

Rawal, Shristi; Hoffman, Howard J.; Chapo, Audrey K.

2015-01-01

Introduction The 2011–14 US National Health and Nutrition Examination Survey chemosensory protocol asks adults to self-rate their orthonasal (via nostrils) and retronasal (via mouth) smell abilities for subsequent odor identification testing. From data collected with a similar protocol, we aimed to identify a self-reported olfactory index that showed the best sensitivity (correctly identifying dysfunction) and specificity (correctly indentifying normosmia) with measured olfaction. Methods In home-based testing, 121 independent-living older women (age 73±7 years) reported their olfactory function by interviewer-administered survey. Olfactory function was measured orthonasally via composite (odor threshold, identification task) or identification task alone. Results Only 16 % of women self-rated “below average” smell function. More women perceived loss of smell (38 %) or flavor (30 %) with aging. The rate of measured dysfunction was 30 % by composite (threshold and identification) and 21.5 % by identification task, the latter misclassifying some mild dysfunction as normosmia. An index of self-rated smell function and perceived loss yielded the most favorable sensitivity (65 %) and specificity (77 %) to measured function. Self-rated olfaction showed better agreement with severe measured dysfunction; mild dysfunction was less noticed. Conclusions Self-reported indices that query about current and perceived changes in smell and flavor with aging showed better sensitivity estimates than those previously reported. Specificity was somewhat lower—some older adults may correctly perceive loss unidentified in a single assessment, or have a retronasal impairment that was undetected by an orthonasal measure. Implications Our findings should inform self-rated measures that screen for severe olfactory dysfunction in clinical/community settings where testing is not routine. PMID:25866597

Nonmotor symptoms in patients with Parkinson disease

PubMed Central

Zhang, Tie-mei; Yu, Shu-yang; Guo, Peng; Du, Yang; Hu, Yang; Piao, Ying-shan; Zuo, Li-jun; Lian, Teng-hong; Wang, Rui-dan; Yu, Qiu-jin; Jin, Zhao; Zhang, Wei

2016-01-01

Abstract Parkinson disease (PD) is usually accompanied by numerous nonmotor symptoms (NMS), such as neuropsychiatric symptoms, sleep disorders, autonomic dysfunctions, and sensory disturbances. However, it is not clear that the factors influencing the occurrence of NMS and its sequence with motor symptoms (MS). We conducted comprehensive assessments of NMS by using 13 scales in 1119 PD patients. A total of 70.8% PD patients present NMS. Olfactory dysfunction tends to occur in PD patients with older age, more severe depression, sleep problems, and autonomic dysfunctions. Older patients are more likely to have olfactory dysfunction before MS than younger patients. Rapid eye movement behavior disorder is more prone to happen in patients with older age, older onset age, more severe depression, sleep problems, and autonomic dysfunctions. Patients with rapid eye movement behavior disorder before MS are older in onset age than after group. Olfactory dysfunction, constipation, rapid eye movement behavior disorder, and depression, as early warning NMSs of PD, connected to each other. There is a clinical heterogeneity that older patients are more likely to have NMS before MS, while younger patients are opposite. PMID:27977578

Olfaction in Parkinson's disease and related disorders.

PubMed

Doty, Richard L

2012-06-01

Olfactory dysfunction is an early 'pre-clinical' sign of Parkinson's disease (PD). The present review is a comprehensive and up-to-date assessment of such dysfunction in PD and related disorders. The olfactory bulb is implicated in the dysfunction, since only those syndromes with olfactory bulb pathology exhibit significant smell loss. The role of dopamine in the production of olfactory system pathology is enigmatic, as overexpression of dopaminergic cells within the bulb's glomerular layer is a common feature of PD and most animal models of PD. Damage to cholinergic, serotonergic, and noradrenergic systems is likely involved, since such damage is most marked in those diseases with the most smell loss. When compromised, these systems, which regulate microglial activity, can influence the induction of localized brain inflammation, oxidative damage, and cytosolic disruption of cellular processes. In monogenetic forms of PD, olfactory dysfunction is rarely observed in asymptomatic gene carriers, but is present in many of those that exhibit the motor phenotype. This suggests that such gene-related influences on olfaction, when present, take time to develop and depend upon additional factors, such as those from aging, other genes, formation of α-synuclein- and tau-related pathology, or lowered thresholds to oxidative stress from toxic insults. The limited data available suggest that the physiological determinants of the early changes in PD-related olfactory function are likely multifactorial and may include the same determinants as those responsible for a number of other non-motor symptoms of PD, such as dysautonomia and sleep disturbances. Copyright © 2011 Elsevier Inc. All rights reserved.

Influenza vaccinations and chemosensory function.

PubMed

Doty, Richard L; Berman, Austin H; Izhar, Mohammad; Hamilton, Hugh B; Villano, Danylko; Vazquez, Britney E; Warrum, Maja N; Mahbob, Mariam

2014-01-01

Although influenza vaccines have saved millions of lives, some have been associated with extremely rare adverse effects such as Guillain-Barré syndrome, Bell's palsy, and optic neuritis. Despite the fact that olfactory loss after an influenza vaccination is noted in one case report, no quantitative olfactory testing was performed. Hence, it is unclear whether, in fact, olfactory dysfunction can be associated with such vaccinations. This study was designed to (1) identify patients from the University of Pennsylvania Smell and Taste Center who attributed their empirically determined chemosensory disturbances to influenza vaccinations and (2) determine whether influenza vaccinations add to the degree of olfactory or gustatory dysfunction due to other causes. A retrospective analysis of self-reported etiologies of 4554 consecutive patients presenting to the University of Pennsylvania Smell and Taste Center with complaints of chemosensory dysfunction was performed. Those who reported dysfunction secondary to influenza vaccinations were identified. Additionally, in a subset of 925 patients for whom detailed inoculation histories were available, it was determined whether the number of lifetime inoculations added to the deficits due to other causes. Nine of the 4554 patients (0.19%) attributed olfactory disturbances to an influenza vaccination. None complained of taste dysfunction. All nine had abnormally low scores on the University of Pennsylvania Smell Identification Test (p < 0.001), with three being anosmic and six microsmic. Seven had elevated phenyl ethyl alcohol detection thresholds (p < 0.05). Two cases exhibited mild-to-moderate loss of whole mouth taste function. Of the 925 patients, no association was evident between the number of lifetime vaccinations and the chemosensory test scores. In accord with previous studies, age and sex were significantly related to the test scores. A very small percentage of the 4554 patients evaluated (0.19%) attributed their chemosensory dysfunction to a prior influenza vaccination. No influences of the number of lifetime influenza vaccinations on the test scores were evident in the subset of 925 patients whose dysfunction was due to other causes.

Effects of Ambient Air Pollution Exposure on Olfaction: A Review

PubMed Central

Ajmani, Gaurav S.; Suh, Helen H.; Pinto, Jayant M.

2016-01-01

Background: Olfactory dysfunction affects millions of people worldwide. This sensory impairment is associated with neurodegenerative disease and significantly decreased quality of life. Exposure to airborne pollutants has been implicated in olfactory decline, likely due to the anatomic susceptibility of the olfactory nerve to the environment. Historically, studies have focused on occupational exposures, but more recent studies have considered effects from exposure to ambient air pollutants. Objectives: To examine all relevant human data evaluating a link between ambient pollution exposure and olfaction and to review supporting animal data in order to examine potential mechanisms for pollution-associated olfactory loss. Methods: We identified and reviewed relevant articles from 1950 to 2015 using PubMed and Web of Science and focusing on human epidemiologic and pathophysiologic studies. Animal studies were included only to support pertinent data on humans. We reviewed findings from these studies evaluating a relationship between environmental pollutant exposure and olfactory function. Results: We identified and reviewed 17 articles, with 1 additional article added from a bibliography search, for a total of 18 human studies. There is evidence in human epidemiologic and pathologic studies that increased exposure to ambient air pollutants is associated with olfactory dysfunction. However, most studies have used proxies for pollution exposure in small samples of convenience. Human pathologic studies, with supporting animal work, have also shown that air pollution can contact the olfactory epithelium, translocate to the olfactory bulb, and migrate to the olfactory cortex. Pollutants can deposit at each location, causing direct damage and disruption of tissue morphology or inducing local inflammation and cellular stress responses. Conclusions: Ambient air pollution may impact human olfactory function. Additional studies are needed to examine air pollution–related olfactory impacts on the general population using measured pollution exposures and to link pollution exposure with olfactory dysfunction and related pathology. Citation: Ajmani GS, Suh HH, Pinto JM. 2016. Effects of ambient air pollution exposure on olfaction: a review. Environ Health Perspect 124:1683–1693; http://dx.doi.org/10.1289/EHP136 PMID:27285588

Sensory Dysfunction

MedlinePlus

... article was contributed by: familydoctor.org editorial staff Categories: Men, Seniors, WomenTags: ageusia, anosmia, chemosensory disorders, decreased appetite, dysgeusia, flavor, olfactory dysfunction, overseasoning food, senses, sensory dysfunction, sensory impairment, smell, taste September ...

The Association Between Olfaction and Depression: A Systematic Review.

PubMed

Kohli, Preeti; Soler, Zachary M; Nguyen, Shaun A; Muus, John S; Schlosser, Rodney J

2016-07-01

Previous studies on the relationship between olfaction and depression have revealed mixed results. In addition, few have focused on the reciprocity of this association. The aim of this study is to combine depression and olfactory data in two separate patient populations to further understand their association. A systematic literature review was conducted using 3 online databases to identify studies correlating olfaction and depression in patients presenting with either primary depression or primary olfactory dysfunction. For the depressed population, weighted means and standard deviations for the Sniffin' Sticks Test and the 40-item Smell Identification Test were combined using 10 studies. For the olfactory dysfunction population, weighted means of Beck's Depression Inventory were combined using 3 studies. Independent t-tests were used to compare differences between groups. Comparing primary depressed patients with controls, depressed patients showed decreased scores in olfactory threshold (6.31±1.38 vs. 6.78±0.88, P = 0.0005), discrimination (12.05±1.44 vs. 12.66±1.36, P = 0.0073), identification (12.57±0.74 vs. 12.98±0.90, P < 0.0001), and 40-Item Smell Identification Test (35.31±1.91 vs. 37.41±1.45, P < 0.0001). In patients with primary olfactory dysfunction, Beck's Depression Inventory scores were significantly different between patients classified as normosmics, hyposmics and anosmics (5.21±4.73 vs. 10.93±9.25 vs. 14.15±5.39, P ≤ 0.0274 for all 3 comparisons). In conclusion, patients with depression have reduced olfactory performance when compared with the healthy controls and conversely, patients with olfactory dysfunction, have symptoms of depression that worsen with severity of smell loss. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Accelerated age-related olfactory decline among type 1 Usher patients

PubMed Central

Ribeiro, João Carlos; Oliveiros, Bárbara; Pereira, Paulo; António, Natália; Hummel, Thomas; Paiva, António; Silva, Eduardo D.

2016-01-01

Usher Syndrome (USH) is a rare disease with hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. A phenotype heterogeneity is reported. Recent evidence indicates that USH is likely to belong to an emerging class of sensory ciliopathies. Olfaction has recently been implicated in ciliopathies, but the scarce literature about olfaction in USH show conflicting results. We aim to evaluate olfactory impairment as a possible clinical manifestation of USH. Prospective clinical study that included 65 patients with USH and 65 normal age-gender-smoking-habits pair matched subjects. A cross culturally validated version of the Sniffin’ Sticks olfaction test was used. Young patients with USH have significantly better olfactory scores than healthy controls. We observe that USH type 1 have a faster ageing olfactory decrease than what happens in healthy subjects, leading to significantly lower olfactory scores in older USH1 patients. Moreover, USH type 1 patients showed significantly higher olfactory scores than USH type 2, what can help distinguishing them. Olfaction represents an attractive tool for USH type classification and pre diagnostic screening due to the low cost and non-invasive nature of the testing. Olfactory dysfunction should be considered among the spectrum of clinical manifestations of Usher syndrome. PMID:27329700

Accelerated age-related olfactory decline among type 1 Usher patients.

PubMed

Ribeiro, João Carlos; Oliveiros, Bárbara; Pereira, Paulo; António, Natália; Hummel, Thomas; Paiva, António; Silva, Eduardo D

2016-06-22

Usher Syndrome (USH) is a rare disease with hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. A phenotype heterogeneity is reported. Recent evidence indicates that USH is likely to belong to an emerging class of sensory ciliopathies. Olfaction has recently been implicated in ciliopathies, but the scarce literature about olfaction in USH show conflicting results. We aim to evaluate olfactory impairment as a possible clinical manifestation of USH. Prospective clinical study that included 65 patients with USH and 65 normal age-gender-smoking-habits pair matched subjects. A cross culturally validated version of the Sniffin' Sticks olfaction test was used. Young patients with USH have significantly better olfactory scores than healthy controls. We observe that USH type 1 have a faster ageing olfactory decrease than what happens in healthy subjects, leading to significantly lower olfactory scores in older USH1 patients. Moreover, USH type 1 patients showed significantly higher olfactory scores than USH type 2, what can help distinguishing them. Olfaction represents an attractive tool for USH type classification and pre diagnostic screening due to the low cost and non-invasive nature of the testing. Olfactory dysfunction should be considered among the spectrum of clinical manifestations of Usher syndrome.

Brain lesion-pattern analysis in patients with olfactory dysfunctions following head trauma

PubMed Central

Lötsch, Jörn; Ultsch, Alfred; Eckhardt, Maren; Huart, Caroline; Rombaux, Philippe; Hummel, Thomas

2016-01-01

The presence of cerebral lesions in patients with neurosensory alterations provides a unique window into brain function. Using a fuzzy logic based combination of morphological information about 27 olfactory-eloquent brain regions acquired with four different brain imaging techniques, patterns of brain damage were analyzed in 127 patients who displayed anosmia, i.e., complete loss of the sense of smell (n = 81), or other and mechanistically still incompletely understood olfactory dysfunctions including parosmia, i.e., distorted perceptions of olfactory stimuli (n = 50), or phantosmia, i.e., olfactory hallucinations (n = 22). A higher prevalence of parosmia, and as a tendency also phantosmia, was observed in subjects with medium overall brain damage. Further analysis showed a lower frequency of lesions in the right temporal lobe in patients with parosmia than in patients without parosmia. This negative direction of the differences was unique for parosmia. In anosmia, and also in phantosmia, lesions were more frequent in patients displaying the respective symptoms than in those without these dysfunctions. In anosmic patients, lesions in the right olfactory bulb region were much more frequent than in patients with preserved sense of smell, whereas a higher frequency of carriers of lesions in the left frontal lobe was observed for phantosmia. We conclude that anosmia, and phantosmia, are the result of lost function in relevant brain areas whereas parosmia is more complex, requiring damaged and intact brain regions at the same time. PMID:26937377

Neuronal generator patterns of olfactory event-related brain potentials in schizophrenia.

PubMed

Kayser, Jürgen; Tenke, Craig E; Malaspina, Dolores; Kroppmann, Christopher J; Schaller, Jennifer D; Deptula, Andrew; Gates, Nathan A; Harkavy-Friedman, Jill M; Gil, Roberto; Bruder, Gerard E

2010-11-01

To better characterize neurophysiologic processes underlying olfactory dysfunction in schizophrenia, nose-referenced 30-channel electroencephalogram was recorded from 32 patients and 35 healthy adults (18 and 18 male) during detection of hydrogen sulfide (constant-flow olfactometer, 200 ms unirhinal exposure). Event-related potentials (ERPs) were transformed to reference-free current source density (CSD) waveforms and analyzed by unrestricted Varimax-PCA. Participants indicated when they perceived a high (10 ppm) or low (50% dilution) odor concentration. Patients and controls did not differ in detection of high (23% misses) and low (43%) intensities and also had similar olfactory ERP waveforms. CSDs showed a greater bilateral frontotemporal N1 sink (305 ms) and mid-parietal P2 source (630 ms) for high than low intensities. N1 sink and P2 source were markedly reduced in patients for high intensity stimuli, providing further neurophysiological evidence of olfactory dysfunction in schizophrenia. Copyright © 2010 Society for Psychophysiological Research.

Scents and Nonsense: Olfactory Dysfunction in Schizophrenia

PubMed Central

Turetsky, Bruce I.; Hahn, Chang-Gyu; Borgmann-Winter, Karin; Moberg, Paul J.

2009-01-01

Among the sensory modalities, olfaction is most closely associated with the frontal and temporal brain regions that are implicated in schizophrenia and most intimately related to the affective and mnemonic functions that these regions subserve. Olfactory probes may therefore be ideal tools through which to assess the structural and functional integrity of the neural substrates that underlie disease-related cognitive and emotional disturbances. Perhaps more importantly, to the extent that early sensory afferents are also disrupted in schizophrenia, the olfactory system—owing to its strategic anatomic location—may be especially vulnerable to such disruption. Olfactory dysfunction may therefore be a sensitive indicator of schizophrenia pathology and may even serve as an “early warning” sign of disease vulnerability or onset. In this article, we review the evidence supporting a primary olfactory sensory disturbance in schizophrenia. Convergent data indicate that structural and functional abnormalities extend from the cortex to the most peripheral elements of the olfactory system. These reflect, in part, a genetically mediated neurodevelopmental etiology. Gross structural and functional anomalies are mirrored by cellular and molecular abnormalities that suggest decreased or faulty innervation and/or dysregulation of intracellular signaling. A unifying mechanistic hypothesis may be the epigenetic regulation of gene expression. With the opportunity to obtain olfactory neural tissue from live patients through nasal epithelial biopsy, the peripheral olfactory system offers a uniquely accessible window through which the pathophysiological antecedents and sequelae of schizophrenia may be observed. This could help to clarify underlying brain mechanisms and facilitate identification of clinically relevant biomarkers. PMID:19793796

Toxin-induced chemosensory dysfunction: A case series and review

PubMed Central

Smith, Wendy M.; Davidson, Terence M.; Murphy, Claire

2013-01-01

Background Toxic chemical exposures are estimated to account for 1–5% of all olfactory disorders. Both olfactory neurons and taste buds are in direct contact with environmental agents because of their relatively unprotected anatomic locations, thereby making them susceptible to damage from acute and chronic toxic exposures. The aim of this study was to illustrate different aspects of the diagnostic and therapeutic approach to this disorder using a series of case reports and review of the literature. Methods Cases were selected for inclusion based on a retrospective chart review of patients who presented to a university-based nasal dysfunction clinic with toxin-induced olfactory or gustatory dysfunction between January 1985 and December 2008. Workup included complete history, otolaryngologic examination, psychophysical testing, and imaging. Results Patient ages ranged from 31 to 67 years (mean, 49.3 years). Etiology of chemosensory impairment included exposure to ammonia, isodecanes, hairdressing chemicals, chemotherapy, gasoline, and intranasal zinc. Five of the seven patients (71%) presented with olfactory dysfunction alone, one patient (14%) presented with dysgeusia alone, and one patient (14%) presented with both smell and taste loss. Only one patient (14%) reported parosmias. Tests of olfaction revealed normosmia in one patient (14%), mild-to-moderate hyposmia in one patient (14%), and severe hyposmia to anosmia in five patients (72%). Both patients who reported taste disorders had hypogeusia on testing. Conclusion This case series illustrates the wide spectrum of this disorder and provides a framework for the workup and treatment of these patients. PMID:19958605

Olfactory dysfunction affects thresholds to trigeminal chemosensory sensations.

PubMed

Frasnelli, J; Schuster, B; Hummel, T

2010-01-14

Next to olfaction and gustation, the trigeminal system represents a third chemosensory system. These senses are interconnected; a loss of olfactory function also leads to a reduced sensitivity in the trigeminal chemosensory system. However, most studies so far focused on comparing trigeminal sensitivity to suprathreshold stimuli; much less data is available with regard to trigeminal sensitivity in the perithreshold range. Therefore we assessed detection thresholds for CO(2), a relatively pure trigeminal stimulus in controls and in patients with olfactory dysfunction (OD). We could show that OD patients exhibit higher detection thresholds than controls. In addition, we were able to explore the effects of different etiologies of smell loss on trigeminal detection thresholds. We could show that in younger subjects, patients suffering from olfactory loss due to head trauma are more severely impaired with regard to their trigeminal sensitivity than patients with isolated congenital anosmia. In older patients, we could not observe any differences between different etiologies, probably due to the well known age-related decrease of trigeminal sensitivity. Furthermore we could show that a betterment of the OD was accompanied by decreased thresholds. This was most evident in patients with postviral OD. In conclusion, factors such as age, olfactory status and etiology of olfactory disorder can affect responsiveness to perithreshold trigeminal chemosensory stimuli. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

Predictors of quality of life outcomes in chronic rhinosinusitis after sinus surgery.

PubMed

Katotomichelakis, Michael; Simopoulos, Efthimios; Tripsianis, Gregory; Balatsouras, Dimitrios; Danielides, Gerasimos; Kourousis, Christos; Livaditis, Miltos; Danielides, Vassilios

2014-04-01

The predictive value of olfaction for quality of life (QoL) recovery after endoscopic sinus surgery (ESS) in chronic rhinosinusitis (CRS) is still underestimated. The aim of this study was to explore the proportion of patients suffering from CRS who experience clinically significant QoL improvement after ESS and identify pre-operative clinical phenotypes that best predict surgical outcomes for QoL, focusing mainly on the role of patients' olfaction. One hundred eleven patients following ESS for CRS and 48 healthy subjects were studied. Olfactory function was expressed by the combined "Threshold Discrimination Identification" score using "Sniffin' sticks" test pre-treatment and 12 months after treatment. All subjects completed validated, widely used QoL questionnaires, specific for olfaction (Questionnaire of Olfactory Deficits: QOD), for assessing psychology (Beck Depression Inventory: BDI) and for general health (Short Form-36: SF-36). Statistically significant improvement of olfactory function by 41.8% and of all QoL questionnaires scores (all p < 0.001) was observed on the 12-month follow-up examination. Clinically significant improvement for QoL was measured in a proportion of 56.8% of patients on QOD, 64.9% on SF-36 and 49.5% on BDI scales results. Although olfactory dysfunction, nasal polyps, female gender, high socio-economic status and non-smoking habits were significantly associated with better QoL results, multivariate logistic regression analysis revealed that only olfactory dysfunction and nasal polyps were independent predictors significantly associated with higher likelihood of clinically significant improvement in all QoL questionnaire results. Olfactory dysfunction and nasal polyps were independent pre-operative predictors for surgical outcomes with regard to QoL results.

Olfaction in Endoscopic Sinus and Skull Base Surgery.

PubMed

Thompson, Christopher F; Kern, Robert C; Conley, David B

2015-10-01

Olfactory dysfunction is a common complaint for patients with chronic rhinosinusitis, because smell loss decreases a patient's quality of life. Smell loss is caused by obstruction from polyps, nasal discharge, and mucosal edema, as well as inflammatory changes within the olfactory epithelium. Addressing olfaction before endoscopic sinus and skull base surgery is important in order to set postoperative expectations, because an improvement in smell is difficult to predict. Several commercially available olfactory testing measures are available and can easily be administered in clinic. During surgery, careful dissection within the olfactory cleft is recommended in order to optimize postoperative olfactory function. Copyright © 2015 Elsevier Inc. All rights reserved.

Olfactory performance segregates effects of anhedonia and anxiety on social function in patients with schizophrenia

PubMed Central

Cieslak, Kristina; Walsh-Messinger, Julie; Stanford, Arielle; Vaez-Azizi, Leila; Antonius, Daniel; Harkavy-Friedman, Jill; Goetz, Deborah; Goetz, Raymond R.; Malaspina, Dolores

2015-01-01

Background Social dysfunction is common among individuals with schizophrenia. While often attributed to anhedonia, social dysfunction could also result from unrecognized anxiety. We examined the contributions of anhedonia and anxiety to social function using olfactory function to examine whether the domains had separate underpinnings. Methods We assessed anhedonia, anxiety and social function as well as olfactory function in well-characterized patients with schizophrenia or schizoaffective disorder and healthy controls. Results We included 56 patients and 37 controls in our study. Patients exhibited significantly higher levels of anhedonia and anxiety than controls, and the domains were highly correlated in patients. The combination of anhedonia and anxiety more strongly predicted social dysfunction than either measure alone. Smell identification was differentially related to the symptoms, with better performance predicting less anhedonia but more social fear in male patients. Limitations The use of self-report measures precludes differentiation between recollected or recounted experience. Aside from smell identification and odour threshold, additional measures of olfaction may be considered for future studies. Conclusion Anhedonia and anxiety were strongly correlated and both negatively impacted social function. The olfactory biomarker results support the conclusion that these domains are separate. Social function in patients with schizophrenia may improve with interventions for anxiety, even in the presence of marked negative symptoms. PMID:26107162

Transcriptome profile and cytogenetic analysis of immortalized neuronally restricted progenitor cells derived from the porcine olfactory bulb

USDA-ARS?s Scientific Manuscript database

Recently, we established and phenotypically characterized an immortalized porcine olfactory bulb neuroblast cell line, OBGF400 (Uebing-Czipura et al., 2008). To facilitate the future application of these cells in studies of neurological dysfunction and neuronal replacement therapies, a comprehensive...

Effects of nutritional status and cognitive ability on olfactory function in geriatric patients.

PubMed

Jin, Sung-Yong; Jeong, Hye Seon; Lee, Jin Woo; Kwon, Ki Ryun; Rha, Ki-Sang; Kim, Yong Min

2016-02-01

The aim of this study was to investigate the prevalence of olfactory dysfunction and evaluate the relationship between olfactory function and nutritional status, comorbidity, and the results of a neurocognitive test in geriatric patients who do not suffer from neurodegenerative disease. A total of 45 patients who visited the Geriatric Health Center of Chungnam National University Hospital were enrolled in this study. Olfactory function was assessed using a Korean Version of Sniffin' Stick Test II. Cognitive status of all participants was assessed with the MMSE-K (Korean version of the Mini-Mental State Examination). Nutritional status was assessed with body mass index, Mini-Nutritional Assessment (MNA), and serum total protein and albumin. A total of 45 participants were enrolled in this study. Of these subjects, 28 were men and 17 were women, with a mean age of 71.7±5.16 years. Nine (20%) were normosmia, 13 (28.9%) were hyposmia, and 23 (51.1%) were anosmia. Thirty-six patients (80%) suffered from olfactory dysfunction (anosmia or hyposmia). MMSE score showed significant correlation with MNA score. There were significant negative correlations between age and total TDI (threshold, discrimination, and identification) score, discrimination score, identification score, and MMSE score. MMSE score showed significant correlation with discrimination score and identification score. However, MNA score did not show any significant correlation with olfactory function test results. Although olfactory function was not influenced by nutritional status, abilities of discrimination and identification of odors were associated with cognitive function in geriatric patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Nasal neuron PET imaging quantifies neuron generation and degeneration

PubMed Central

Van de Bittner, Genevieve C.; Riley, Misha M.; Cao, Luxiang; Herrick, Scott P.; Ricq, Emily L.; O’Neill, Michael J.; Ahmed, Zeshan; Murray, Tracey K.; Smith, Jaclyn E.; Wang, Changning; Schroeder, Frederick A.; Albers, Mark W.; Hooker, Jacob M.

2017-01-01

Olfactory dysfunction is broadly associated with neurodevelopmental and neurodegenerative diseases and predicts increased mortality rates in healthy individuals. Conventional measurements of olfactory health assess odor processing pathways within the brain and provide a limited understanding of primary odor detection. Quantification of the olfactory sensory neurons (OSNs), which detect odors within the nasal cavity, would provide insight into the etiology of olfactory dysfunction associated with disease and mortality. Notably, OSNs are continually replenished by adult neurogenesis in mammals, including humans, so OSN measurements are primed to provide specialized insights into neurological disease. Here, we have evaluated a PET radiotracer, [11C]GV1-57, that specifically binds mature OSNs and quantifies the mature OSN population in vivo. [11C]GV1-57 monitored native OSN population dynamics in rodents, detecting OSN generation during postnatal development and aging-associated neurodegeneration. [11C]GV1-57 additionally measured rates of neuron regeneration after acute injury and early-stage OSN deficits in a rodent tauopathy model of neurodegenerative disease. Preliminary assessment in nonhuman primates suggested maintained uptake and saturable binding of [18F]GV1-57 in primate nasal epithelium, supporting its translational potential. Future applications for GV1-57 include monitoring additional diseases or conditions associated with olfactory dysregulation, including cognitive decline, as well as monitoring effects of neuroregenerative or neuroprotective therapeutics. PMID:28112682

Olfactory dysfunction correlates with amyloid-beta burden in an Alzheimer's disease mouse model.

PubMed

Wesson, Daniel W; Levy, Efrat; Nixon, Ralph A; Wilson, Donald A

2010-01-13

Alzheimer's disease often results in impaired olfactory perceptual acuity-a potential biomarker of the disorder. However, the usefulness of olfactory screens to serve as informative indicators of Alzheimer's is precluded by a lack of knowledge regarding why the disease impacts olfaction. We addressed this question by assaying olfactory perception and amyloid-beta (Abeta) deposition throughout the olfactory system in mice that overexpress a mutated form of the human amyloid-beta precursor protein. Such mice displayed progressive olfactory deficits that mimic those observed clinically-some evident at 3 months of age. Also, at 3 months of age, we observed nonfibrillar Abeta deposition within the olfactory bulb-earlier than deposition within any other brain region. There was also a correlation between olfactory deficits and the spatial-temporal pattern of Abeta deposition. Therefore, nonfibrillar, versus fibrillar, Abeta-related mechanisms likely contribute to early olfactory perceptual loss in Alzheimer's disease. Furthermore, these results present the odor cross-habituation test as a powerful behavioral assay, which reflects Abeta deposition and thus may serve to monitor the efficacy of therapies aimed at reducing Abeta.

Cigarette Smoke Delays Regeneration of the Olfactory Epithelium in Mice.

PubMed

Ueha, Rumi; Ueha, Satoshi; Sakamoto, Takashi; Kanaya, Kaori; Suzukawa, Keigo; Nishijima, Hironobu; Kikuta, Shu; Kondo, Kenji; Matsushima, Kouji; Yamasoba, Tatsuya

2016-08-01

The olfactory system is a unique part of the mammalian nervous system due to its capacity for neurogenesis and the replacement of degenerating receptor neurons. Cigarette smoking is a major cause of olfactory dysfunction. However, the mechanisms by which cigarette smoke impairs the regenerative olfactory receptor neurons (ORNs) remain unclear. Here, we investigated the influence of cigarette smoke on ORN regeneration following methimazole-induced ORN injury. Administration of methimazole caused detachment of the olfactory epithelium from the basement membrane and induced olfactory dysfunction, thus enabling us to analyze the process of ORN regeneration. We found that intranasal administration of cigarette smoke solution (CSS) suppressed the recovery of ORNs and olfaction following ORN injury. Defective ORN recovery in CSS-treated mice was not associated with any change in the number of SOX2(+) ORN progenitor cells in the basal layer of the OE, but was associated with impaired recovery of GAP43(+) immature ORNs. In the nasal mucosa, mRNA expression levels of neurotrophic factors such as brain-derived neurotrophic factor, neurotrophin-3, neurotrophin-5, glial cell-derived neurotrophic factor, and insulin-like growth factor-1 (IGF-1) were increased following OE injury, whereas CSS administration decreased the ORN injury-induced IGF-1 expression. Administration of recombinant human IGF-1 prevented the CSS-induced suppression of ORN recovery following injury. These results suggest that CSS impairs regeneration of ORNs by suppressing the development of immature ORNs from ORN progenitors, at least partly by reducing IGF-1 in the nasal mucosa.

Changes in olfactory bulb volume following lateralized olfactory training.

PubMed

Negoias, S; Pietsch, K; Hummel, T

2017-08-01

Repeated exposure to odors modifies olfactory function. Consequently, "olfactory training" plays a significant role in hyposmia treatment. In addition, numerous studies show that the olfactory bulb (OB) volume changes in disorders associated with olfactory dysfunction. Aim of this study was to investigate whether and how olfactory bulb volume changes in relation to lateralized olfactory training in healthy people. Over a period of 4 months, 97 healthy participants (63 females and 34 males, mean age: 23.74 ± 4.16 years, age range: 19-43 years) performed olfactory training by exposing the same nostril twice a day to 4 odors (lemon, rose, eucalyptus and cloves) while closing the other nostril. Before and after olfactory training, magnetic resonance imaging (MRI) scans were performed to measure OB volume. Furthermore, participants underwent lateralized odor threshold and odor identification testing using the "Sniffin' Sticks" test battery.OB volume increased significantly after olfactory training (11.3 % and 13.1 % respectively) for both trained and untrained nostril. No significant effects of sex, duration and frequency of training or age of the subjects were seen. Interestingly, PEA odor thresholds worsened after training, while olfactory identification remained unchanged.These data show for the first time in humans that olfactory training may involve top-down process, which ultimately lead to a bilateral increase in olfactory bulb volume.

Comparison of subjective olfaction ratings in patients with and without olfactory disorders.

PubMed

Haxel, B R; Bertz-Duffy, S; Fruth, K; Letzel, S; Mann, W J; Muttray, A

2012-07-01

Olfactory dysfunction is common. The reliability of self-assessment tools for smell testing is still controversial. This study aimed to provide new data about the accuracy of olfactory self-assessment compared with a standardised smell test. Prospective, controlled, cohort study of patients with olfactory disorders and healthy controls. Ninety-six patients with a smell deficit and 71 controls were asked to rate their sense of smell on a visual analogue scale. Their olfactory abilities were also evaluated with the Sniffin' Sticks tests. The whole cohort showed a significant correlation between visual analogue scale smell scores and Sniffin' Sticks total scores. This correlation was also significant in the patient group, but not in the control group. These results were independent of olfactory deficit aetiology and subject age. Self-assessment of olfaction is only a reliable indicator in smell-impaired patients, not in healthy controls. For an accurate assessment of olfaction, reliable, standardised tests are needed.

Olfaction preservation after removal of large tuberculum sellae meningiomas via a superior interhemispheric approach. A quantitative and qualitative study.

PubMed

Hannequin, P; Paviot, A; Chaussy, O; Gilard, V; Cébula, H; Marie, J-P; Proust, F

2015-10-01

We present a prospective series of tuberculum sellae meningioma (TSM) resected via a superior interhemispheric (IH) approach in 10 patients who preoperatively and postoperatively underwent extensive olfaction testing using a standardised test battery. This prospective longitudinal study evaluated the olfactory function after TSM resection. The resection was performed via a superior interhemispheric (IH) approach. The quantitative and qualitative analyses of the olfactory function were assessed with the Biolfa(®) olfactory test (at 6 months). Between November 2009 and April 2012, 10 consecutive patients with symptomatic TSM and preserved olfactory function were operated via a superior IH approach. For the self-evaluation criteria of the olfactory function, the mean preoperative visual analog scale score was 8.8. The mean preoperative total quantitative (/27) scored 18.2 ± 6.3 for this cohort of 10 patients. In the postoperative period, the mean total score decreased non-significantly to 15.8 ± 8.8 (Wilcoxon test, P = 0.085). The mean preoperative qualitative score (/8) was 5.5 ± 1.7 and in the postoperative period decreased, non-significantly, to 4.7 ± 2.6 (Wilcoxon test, P = 0.12). The olfactory function was quantitatively and qualitatively preserved in 6 patients (60%), but a postoperative deterioration occurred in 2 (20%) and an anosmia in 2 (20%). Size and invasive characteristics of the meningioma determined the post-surgical deterioration. Olfaction is an important factor of emotional and social life, which needs to be integrated into the challenge regarding the resection of TSM. The risks of nerve damage are reviewed. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Olfactory discrimination predicts cognitive decline among community-dwelling older adults

PubMed Central

Sohrabi, H R; Bates, K A; Weinborn, M G; Johnston, A N B; Bahramian, A; Taddei, K; Laws, S M; Rodrigues, M; Morici, M; Howard, M; Martins, G; Mackay-Sim, A; Gandy, S E; Martins, R N

2012-01-01

The presence of olfactory dysfunction in individuals at higher risk of Alzheimer's disease has significant diagnostic and screening implications for preventive and ameliorative drug trials. Olfactory threshold, discrimination and identification can be reliably recorded in the early stages of neurodegenerative diseases. The current study has examined the ability of various olfactory functions in predicting cognitive decline in a community-dwelling sample. A group of 308 participants, aged 46–86 years old, were recruited for this study. After 3 years of follow-up, participants were divided into cognitively declined and non-declined groups based on their performance on a neuropsychological battery. Assessment of olfactory functions using the Sniffin' Sticks battery indicated that, contrary to previous findings, olfactory discrimination, but not olfactory identification, significantly predicted subsequent cognitive decline (odds ratio=0.869; P<0.05; 95% confidence interval=0.764−0.988). The current study findings confirm previously reported associations between olfactory and cognitive functions, and indicate that impairment in olfactory discrimination can predict future cognitive decline. These findings further our current understanding of the association between cognition and olfaction, and support olfactory assessment in screening those at higher risk of dementia. PMID:22832962

Olfactory discrimination predicts cognitive decline among community-dwelling older adults.

PubMed

Sohrabi, H R; Bates, K A; Weinborn, M G; Johnston, A N B; Bahramian, A; Taddei, K; Laws, S M; Rodrigues, M; Morici, M; Howard, M; Martins, G; Mackay-Sim, A; Gandy, S E; Martins, R N

2012-05-22

The presence of olfactory dysfunction in individuals at higher risk of Alzheimer's disease has significant diagnostic and screening implications for preventive and ameliorative drug trials. Olfactory threshold, discrimination and identification can be reliably recorded in the early stages of neurodegenerative diseases. The current study has examined the ability of various olfactory functions in predicting cognitive decline in a community-dwelling sample. A group of 308 participants, aged 46-86 years old, were recruited for this study. After 3 years of follow-up, participants were divided into cognitively declined and non-declined groups based on their performance on a neuropsychological battery. Assessment of olfactory functions using the Sniffin' Sticks battery indicated that, contrary to previous findings, olfactory discrimination, but not olfactory identification, significantly predicted subsequent cognitive decline (odds ratio = 0.869; P<0.05; 95% confidence interval = 0.764-0.988). The current study findings confirm previously reported associations between olfactory and cognitive functions, and indicate that impairment in olfactory discrimination can predict future cognitive decline. These findings further our current understanding of the association between cognition and olfaction, and support olfactory assessment in screening those at higher risk of dementia.

Osmophobia and olfactory functions in patients with migraine.

PubMed

Kayabaşoglu, Gürkan; Altundag, Aytug; Kotan, Dilcan; Dizdar, Denizhan; Kaymaz, Recep

2017-02-01

Olfactory dysfunction and migraine has been associated for a long time. In this study, we planned to compare olfactory functions in patients with migraine and osmophobia with patients having migraine but no osmophobia, in addition with a normal control group using "Sniffin' Sticks" test. The main distinction of this study is that all qualitative and quantitative properties of olfactory functions; threshold, discrimination and identification, are evaluated separately and jointly. Thirty healthy person aged between 16 and 56 (18 women, 12 men) and 60 migraine patients aged between 15 and 54 (39 women, 21 man) were included in the study. All patients have been inquired about osmophobia and have been assessed with Hedonic tone assessment. Osmophobia has been tested for perfume, cigarette smoke, leather, stale food, soy sauce, fish, spices and coffee smells. Olfactory functions has been assessed with "Sniffin' Sticks" smell test. Thresholds, discrimination and identification have been determined for each patient. In migraine patients with osmophobia, threshold was 7.75 ± 2.3, in migraine patients without osmophobia threshold was 8.25 ± 1.5 and threshold was 10.75 ± 1.3 for the control group. Discrimination score was 6 ± 1.2 in migraine patients with osmophobia, 9 ± 0.8 in patients without osmophobia and was 12 ± 1.4 in the control group. In migraine patient with or without osmophobia Threshold/Discrimination/Identification (TDI) scores were lower than the control group. The most important parameter in our study is that discrimination scores were especially lower in patients with osmophobia. We believe that this decrease in discrimination in migraine patients with osmophobia; who claim that they smell everything and they are sensitive to all smells, is significant. Further studies about smell discrimination will help better understand some conditions; especially anosmia and hyposmia after upper respiratory tract infections and parosmia.

Hyperlipidemic Diet Causes Loss of Olfactory Sensory Neurons, Reduces Olfactory Discrimination, and Disrupts Odor-Reversal Learning

PubMed Central

Thiebaud, Nicolas; Johnson, Melissa C.; Butler, Jessica L.; Bell, Genevieve A.; Ferguson, Kassandra L.; Fadool, Andrew R.; Fadool, James C.; Gale, Alana M.; Gale, David S.

2014-01-01

Currently, 65% of Americans are overweight, which leads to well-supported cardiovascular and cognitive declines. Little, however, is known concerning obesity's impact on sensory systems. Because olfaction is linked with ingestive behavior to guide food choice, its potential dysfunction during obesity could evoke a positive feedback loop to perpetuate poor ingestive behaviors. To determine the effect of chronic energy imbalance and reveal any structural or functional changes associated with obesity, we induced long-term, diet-induced obesity by challenging mice to high-fat diets: (1) in an obesity-prone (C57BL/6J) and obesity-resistant (Kv1.3−/−) line of mice, and compared this with (2) late-onset, genetic-induced obesity in MC4R−/− mice in which diabetes secondarily precipitates after disruption of the hypothalamic axis. We report marked loss of olfactory sensory neurons and their axonal projections after exposure to a fatty diet, with a concomitant reduction in electro-olfactogram amplitude. Loss of olfactory neurons and associated circuitry is linked to changes in neuronal proliferation and normal apoptotic cycles. Using a computer-controlled, liquid-based olfactometer, mice maintained on fatty diets learn reward-reinforced behaviors more slowly, have deficits in reversal learning demonstrating behavioral inflexibility, and exhibit reduced olfactory discrimination. When obese mice are removed from their high-fat diet to regain normal body weight and fasting glucose, olfactory dysfunctions are retained. We conclude that chronic energy imbalance therefore presents long-lasting structural and functional changes in the operation of the sensory system designed to encode external and internal chemical information and leads to altered olfactory- and reward-driven behaviors. PMID:24828650

Altered Odor-Induced Brain Activity as an Early Manifestation of Cognitive Decline in Patients With Type 2 Diabetes.

PubMed

Zhang, Zhou; Zhang, Bing; Wang, Xin; Zhang, Xin; Yang, Qing X; Qing, Zhao; Lu, Jiaming; Bi, Yan; Zhu, Dalong

2018-05-01

Type 2 diabetes is reported to be associated with olfactory dysfunction and cognitive decline. However, whether and how olfactory neural circuit abnormalities involve cognitive impairment in diabetes remains uncovered. This study thus aimed to investigate olfactory network alterations and the associations of odor-induced brain activity with cognitive and metabolic parameters in type 2 diabetes. Participants with normal cognition, including 51 patients with type 2 diabetes and 41 control subjects without diabetes, underwent detailed cognitive assessment, olfactory behavior tests, and odor-induced functional MRI measurements. Olfactory brain regions showing significantly different activation between the two groups were selected for functional connectivity analysis. Compared with the control subjects, patients with diabetes demonstrated significantly lower olfactory threshold score, decreased brain activation, and disrupted functional connectivity in the olfactory network. Positive associations of the disrupted functional connectivity with decreased neuropsychology test scores and reduced pancreatic function were observed in patients with diabetes. Notably, the association between pancreatic function and executive function was mediated by olfactory behavior and olfactory functional connectivity. Our results suggested the alteration of olfactory network is present before clinically measurable cognitive decrements in type 2 diabetes, bridging the gap between the central olfactory system and cognitive decline in diabetes. © 2018 by the American Diabetes Association.

Differential Olfactory Identification in Children with Autism and Asperger's Disorder: A Comparative and Longitudinal Study

ERIC Educational Resources Information Center

May, Tamara; Brewer, Warrick J.; Rinehart, Nicole J.; Enticott, Peter G.; Brereton, Avril V.; Tonge, Bruce J.

2011-01-01

Key theories of autism implicate orbitofrontal cortex (OFC) compromise, while olfactory identification (OI) deficits are associated with OFC dysfunction. This study aimed to complete a 5-year follow-up of children with high-functioning autism (HFA) who previously lacked the normal age-OI association; and compare unirhinal-OI in children with HFA,…

The optimal evaluation and management of patients with a gradual onset of olfactory loss.

PubMed

Enriquez, Karla; Lehrer, Eduardo; Mullol, Joaquim

2014-02-01

The aim of this review is to provide an overview of the causes of olfactory dysfunction, their evaluation and management, with a main focus on the gradual/progressive loss of smell. As the sense of smell gives us essential information about our environment, its loss can cause nutritional and social problems while threatening an individual's safety. Recent surveys have shown quite a substantial prevalence of hyposmia (one out of four people) and anosmia (one out of 200 people) in a variety of populations. Nasal inflammatory diseases such as allergic rhinitis and predominantly chronic rhinosinusitis account for the major and common causes of gradual/progressive loss of smell. However, they are also among the most successfully treated forms of olfactory dysfunction. The management of gradual/progressive smell deficit must always address its etiological causes. In most cases, a detailed medical history and nasal examination, smell testing, and imaging will help to establish an appropriate diagnosis. In addition to anti-inflammatory therapy, mainly nasal and systemic corticosteroids, recent investigations on smell training suggest that the controlled exposure to selected odors may increase olfactory performance. See the Video Supplementary Digital Content 1 (http://links.lww.com/COOH/A8).

Fox smell abrogates the effect of herbal odor to prolong mouse cardiac allograft survival.

PubMed

Jin, Xiangyuan; Uchiyama, Masateru; Zhang, Qi; Niimi, Masanori

2014-05-09

Herbal medicines have unique odors, and the act of smelling may have modulatory effects on the immune system. We investigated the effect of olfactory exposure to Tokishakuyaku-san (TJ-23), a Japanese herbal medicine, on alloimmune responses in a murine model of cardiac allograft transplantation. Naïve or olfactory-dysfunctional CBA mice underwent transplantation of a C57BL/6 heart and were exposed to the odor of TJ-23 until rejection. Some naïve CBA recipients of an allograft were given olfactory exposure to Sairei-to (TJ-114), trimethylthiazoline (TMT), individual components of TJ-23, or a TJ-23 preparation lacking one component. Adoptive transfer studies were performed to determine whether regulatory cells were generated. Untreated CBA mice rejected their C57BL/6 allografts acutely, as did olfactory-dysfunctional CBA mice exposed to the odor of TJ-23. CBA recipients of a C57BL/6 heart given olfactory exposure to TJ-23 had significantly prolonged allograft survival, whereas those exposed to the odor of TJ-114, TMT, one component of TJ-23, or TJ-23 lacking a component did not. Secondary allograft recipients that were given, at 30 days after transplantation, either whole splenocytes, CD4+ cells, or CD4+CD25+ cells from primary recipients exposed to the odor of TJ-23 had indefinitely prolonged allograft survival. Prolonged survival of cardiac allografts and generation of regulatory cells was associated with exposure to the odor of TJ-23 in our model. The olfactory area of the brain may have a role in the modulation of immune responses.

Morphology of the olfactory system in the predatory mite Phytoseiulus persimilis.

PubMed

van Wijk, Michiel; Wadman, Wytse J; Sabelis, Maurice W

2006-01-01

The predatory mite Phytoseiulus persimilis locates its prey, the two-spotted spider mite, by means of herbivore-induced plant volatiles. The olfactory response to this quantitatively and qualitatively variable source of information is particularly well documented. The mites perform this task with a peripheral olfactory system that consists of just five putative olfactory sensilla that reside in a dorsal field at the tip of their first pair of legs. The receptor cells innervate a glomerular olfactory lobe just ventral of the first pedal ganglion. We have made a 3D reconstruction of the caudal half of the olfactory lobe in adult females. The glomerular organization as well as the glomerular innervation appears conserved across different individuals. The adult females have, by approximation, a 1:1 ratio of olfactory receptor cells to olfactory glomeruli.

Comparative effects of cadmium, zinc, arsenic and chromium on olfactory-mediated neurobehavior and gene expression in larval zebrafish (Danio rerio).

PubMed

Heffern, Kevin; Tierney, Keith; Gallagher, Evan P

2018-05-28

Studies have shown that olfactory-mediated behaviors that are critical to survival can be disrupted by exposure to certain metals. Polluted waterways often contain elevated levels of metals, yet only a subset have been characterized for their potential to cause olfactory toxicity. A larval zebrafish behavioral assay was developed to characterize concentration-response curves for zinc (Zn), hexavalent chromium (Cr), and arsenate (As) olfaction inhibition. Cadmium (Cd), an established olfactory toxicant, was used as a positive control. As expected, following a 24-hour exposure to Cd, we observed a reduced response to taurocholic acid (TCA), a substrate for ciliated olfactory sensory neurons (OSNs), thus validating the behavioral assay. Zn exposure similarly decreased the olfactory response toward TCA, (IC 50 : 36 μg/L and 76 μg/L, for Cd and Zn, respectively). The response towards a secondary odorant L-cysteine (Cys), a substrate for ciliated and microvillous OSNs, was significantly altered by both Cd and Zn exposure, although the response to Cys was not completely removed in Zn treated larvae, suggesting preferential toxicity towards ciliated OSNs. No significant changes in olfactory responses were observed following Cr and As exposures. Exposures to binary mixtures of Cd and Zn indicated that Zn had a protective effect against Cd toxicity at low Zn concentrations. QuantiGene (QDP) RNA analysis revealed Cd to be a potent inducer of metallothionein 2 (mt2) mRNA in zebrafish larvae, and Zn to be a weak mt2 inducer, suggesting a protective role of mt2 in Cd and Zn olfactory injury. By contrast, QDP analysis of eight other genes important in mitigating the effects of oxidative stress suggested an antioxidant response to Cd, but not Zn, As, and Cr suggesting that oxidative stress was not a primary mechanism of Zn-induced olfactory dysfunction. In summary, our study indicates that Zn inhibits zebrafish olfaction at environmental concentrations and may potentially mitigate Cd induced olfactory dysfunction when present in mixtures. The zebrafish behavioral trough assay incorporating the odorants L-cysteine and TCA is an effective assay to assess the effects of metals on olfactory function. Copyright © 2018 Elsevier B.V. All rights reserved.

Health-related and specific olfaction-related quality of life in patients with chronic functional anosmia or severe hyposmia.

PubMed

Neuland, Claudia; Bitter, Thomas; Marschner, Heike; Gudziol, Hilmar; Guntinas-Lichius, Orlando

2011-04-01

To measure health-related and olfaction-related quality of life (QoL) in patients with permanent, severe hyposmia or functional anosmia. A case study in a university ENT department of patients with severe olfactory dysfunction defined by Sniffin' Sticks olfactory test kit with a score for odor threshold, discrimination, and identification (TDI) < 20 and a dysfunction lasting longer than 6 months. Assessment of QoL by using the SF-36 Health Survey questionnaire and the Questionnaire for Olfactory Dysfunction (QOD). A total of 958 patients were tested for smell disturbances from 1999 to 2009. Surveys were mailed to 527 patients who fulfilled the inclusion criteria; 280 (53%) returned completed surveys. All SF-36 domains in severely hyposmic and anosmic patients were lower than in the German normal population. Lower SF-36 QoL was found for some domains in female patients, older patients, and hyposmic patients (P < .05 for all groups). Based on the QOD, women showed more parosmia, and anosmic patients had more olfactory-related impairment (P < .05 for both); in general, higher olfactory impairment and higher parosmia score measured by QOD correlated with lower TDI values (all P < .05). Multivariate analysis revealed, for SF-36 domains, the following independent risk factors: female sex was a risk factor for bodily pain; higher age was a risk factor for physical functioning and role, bodily pain, and general health; hyposmia was a risk factor for bodily pain and mental health; QOD QoL was a risk factor for all SF-36 scales; and QOD parosmia was a risk factor for physical role (all P < .05). QoL is severely impaired in patients with chronic severe hyposmia or anosmia. The QOD allows a more olfaction-specific assessment of QoL than the SF-36 instrument. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

The olfactory nerve: a shortcut for influenza and other viral diseases into the central nervous system.

PubMed

van Riel, Debby; Verdijk, Rob; Kuiken, Thijs

2015-01-01

The olfactory nerve consists mainly of olfactory receptor neurons and directly connects the nasal cavity with the central nervous system (CNS). Each olfactory receptor neuron projects a dendrite into the nasal cavity on the apical side, and on the basal side extends its axon through the cribriform plate into the olfactory bulb of the brain. Viruses that can use the olfactory nerve as a shortcut into the CNS include influenza A virus, herpesviruses, poliovirus, paramyxoviruses, vesicular stomatitis virus, rabies virus, parainfluenza virus, adenoviruses, Japanese encephalitis virus, West Nile virus, chikungunya virus, La Crosse virus, mouse hepatitis virus, and bunyaviruses. However, mechanisms of transport via the olfactory nerve and subsequent spread through the CNS are poorly understood. Proposed mechanisms are either infection of olfactory receptor neurons themselves or diffusion through channels formed by olfactory ensheathing cells. Subsequent virus spread through the CNS could occur by multiple mechanisms, including trans-synaptic transport and microfusion. Viral infection of the CNS can lead to damage from infection of nerve cells per se, from the immune response, or from a combination of both. Clinical consequences range from nervous dysfunction in the absence of histopathological changes to severe meningoencephalitis and neurodegenerative disease. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Olfactory Function and Associated Clinical Correlates in Former National Football League Players

PubMed Central

Alosco, Michael L.; Jarnagin, Johnny; Tripodis, Yorghos; Platt, Michael; Martin, Brett; Chaisson, Christine E.; Baugh, Christine M.; Fritts, Nathan G.; Cantu, Robert C.

2017-01-01

Abstract Professional American football players incur thousands of repetitive head impacts (RHIs) throughout their lifetime. The long-term consequences of RHI are not well characterized, but may include olfactory dysfunction. RHI has been associated with changes to brain regions involved in olfaction, and olfactory impairment is common after traumatic brain injury. Olfactory dysfunction is a frequent early sequelae of neurodegenerative diseases (e.g., Alzheimer's disease), and RHI is associated with the neurodegenerative disease, chronic traumatic encephalopathy (CTE). We examined olfaction, and its association with clinical measures, in former National Football League (NFL) players. Ninety-five former NFL players (ages 40–69) and 28 same-age controls completed a neuropsychological and neuropsychiatric evaluation as part of a National Institutes of Health–funded study. The Brief Smell Identification Test (B-SIT) assessed olfaction. Principal component analysis generated a four-factor structure of the clinical measures: behavioral/mood, psychomotor speed/executive function, and verbal and visual memory. Former NFL players had worse B-SIT scores relative to controls (p = 0.0096). A B-SIT cutoff of 11 had the greatest accuracy (c-statistic = 0.61) and specificity (79%) for discriminating former NFL players from controls. In the former NFL players, lower B-SIT scores correlated with greater behavioral/mood impairment (p = 0.0254) and worse psychomotor speed/executive functioning (p = 0.0464) after controlling for age and education. Former NFL players exhibited lower olfactory test scores relative to controls, and poorer olfactory test performance was associated with worse neuropsychological and neuropsychiatric functioning. Future work that uses more-comprehensive tests of olfaction and structural and functioning neuroimaging may improve understanding on the association between RHI and olfaction. PMID:27430424

Olfactory Function and Associated Clinical Correlates in Former National Football League Players.

PubMed

Alosco, Michael L; Jarnagin, Johnny; Tripodis, Yorghos; Platt, Michael; Martin, Brett; Chaisson, Christine E; Baugh, Christine M; Fritts, Nathan G; Cantu, Robert C; Stern, Robert A

2017-02-15

Professional American football players incur thousands of repetitive head impacts (RHIs) throughout their lifetime. The long-term consequences of RHI are not well characterized, but may include olfactory dysfunction. RHI has been associated with changes to brain regions involved in olfaction, and olfactory impairment is common after traumatic brain injury. Olfactory dysfunction is a frequent early sequelae of neurodegenerative diseases (e.g., Alzheimer's disease), and RHI is associated with the neurodegenerative disease, chronic traumatic encephalopathy (CTE). We examined olfaction, and its association with clinical measures, in former National Football League (NFL) players. Ninety-five former NFL players (ages 40-69) and 28 same-age controls completed a neuropsychological and neuropsychiatric evaluation as part of a National Institutes of Health-funded study. The Brief Smell Identification Test (B-SIT) assessed olfaction. Principal component analysis generated a four-factor structure of the clinical measures: behavioral/mood, psychomotor speed/executive function, and verbal and visual memory. Former NFL players had worse B-SIT scores relative to controls (p = 0.0096). A B-SIT cutoff of 11 had the greatest accuracy (c-statistic = 0.61) and specificity (79%) for discriminating former NFL players from controls. In the former NFL players, lower B-SIT scores correlated with greater behavioral/mood impairment (p = 0.0254) and worse psychomotor speed/executive functioning (p = 0.0464) after controlling for age and education. Former NFL players exhibited lower olfactory test scores relative to controls, and poorer olfactory test performance was associated with worse neuropsychological and neuropsychiatric functioning. Future work that uses more-comprehensive tests of olfaction and structural and functioning neuroimaging may improve understanding on the association between RHI and olfaction.

Olfactory dysfunction, olfactory bulb pathology and urban air pollution

PubMed Central

Calderón-Garcidueñas, Lilian; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Osnaya, Norma; González-Maciel, Angelica; Reynoso-Robles, Rafael; Villarreal-Calderon, Rafael; Herritt, Lou; Brooks, Diane; Keefe, Sheyla; Palacios-Moreno, Juan; Villarreal-Calderon, Rodolfo; Torres-Jardón, Ricardo; Medina-Cortina, Humberto; Delgado-Chávez, Ricardo; Aiello-Mora, Mario; Maronpot, Robert R.; Doty, Richard L

2010-01-01

Mexico City (MC) residents are exposed to severe air pollution and exhibit olfactory bulb inflammation. We compared the olfactory function of individuals living under conditions of extreme air pollution to that of controls from a relatively clean environment and explore associations between olfaction scores, apolipoprotein E (APOE) status, and pollution exposure. The olfactory bulbs (OBs) of 35 MC and 9 controls 20.8 ± 8.5 y were assessed by light and electron microscopy. The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 62 MC / 25 controls 21.2 ±2.7 y. MC subjects had significantly lower UPSIT scores: 34.24 ± 0.42 versus controls 35.76 ± 0.40, p=0.03. Olfaction deficits were present in 35.5% MC and 12% of controls. MC APOE ε 4 carriers failed 2.4 ± 0.54 items in the 10-item smell identification scale from the UPSIT related to Alzheimer's disease, while APOE 2/3 and 3/3 subjects failed 1.36 ± 0.16 items, p = 0.01. MC residents exhibited OB endothelial hyperplasia, neuronal accumulation of particles (2/35), and immunoreactivity to beta amyloid βA42 (29/35) and/or α-synuclein (4/35) in neurons, glial cells and/or blood vessels. Ultrafine particles were present in OBs endothelial cytoplasm and basement membranes. Control OBs were unremarkable. Air pollution exposure is associated with olfactory dysfunction and OB pathology, APOE 4 may confer greater susceptibility to such abnormalities, and ultrafine particles could play a key role in the OB pathology. This study contributes to our understanding of the influences of air pollution on olfaction and its potential contribution to neurodegeneration. PMID:19297138

Olfactory identification in amnestic and non-amnestic mild cognitive impairment and its neuropsychological correlates.

PubMed

Vyhnalek, Martin; Magerova, Hana; Andel, Ross; Nikolai, Tomas; Kadlecova, Alexandra; Laczo, Jan; Hort, Jakub

2015-02-15

Olfactory identification impairment in amnestic mild cognitive impairment (aMCI) patients is well documented and considered to be caused by underlying Alzheimer's disease (AD) pathology, contrasting with less clear evidence in non-amnestic MCI (naMCI). The aim was to (a) compare the degree of olfactory identification dysfunction in aMCI, naMCI, controls and mild AD dementia and (b) assess the relation between olfactory identification and cognitive performance in aMCI compared to naMCI. 75 patients with aMCI and 32 with naMCI, 26 patients with mild AD and 27 controls underwent the multiple choice olfactory identification Motol Hospital Smell Test with 18 different odors together with a comprehensive neuropsychological examination. Controlling for age and gender, patients with aMCI and naMCI did not differ significantly in olfactory identification and both performed significantly worse than controls (p<0.001), albeit also better than patients with mild AD (p<.001). In the aMCI group, higher scores on MMSE, verbal and non-verbal memory and visuospatial tests were significantly related to better olfactory identification ability. Conversely, no cognitive measure was significantly related to olfactory performance in naMCI. Olfactory identification is similarly impaired in aMCI and naMCI. Olfactory impairment is proportional to cognitive impairment in aMCI but not in naMCI. Copyright © 2015. Published by Elsevier B.V.

Immunohistochemical characterization of human olfactory tissue

PubMed Central

Holbrook, Eric H.; Wu, Enming; Curry, William T.; Lin, Derrick T.; Schwob, James E.

2011-01-01

Objectives/Hypothesis The pathophysiology underlying human olfactory disorders is poorly understood because biopsying the olfactory epithelium (OE) can be unrepresentative and extensive immunohistochemical analysis is lacking. Autopsy tissue enriches our grasp of normal and abnormal olfactory immunohistology and guides the sampling of the OE by biopsy. Furthermore, a comparison of the molecular phenotype of olfactory epithelial cells between rodents and humans will improve our ability to correlate human histopathology with olfactory dysfunction. Study Design An immunohistochemical analysis of human olfactory tissue using a comprehensive battery of proven antibodies. Methods Human olfactory mucosa obtained from 21 autopsy specimens was analyzed with immunohistochemistry. The position and extent of olfactory mucosa was assayed by staining whole mounts with neuronal markers. Sections of the OE were analyzed with an extensive group of antibodies directed against cytoskeletal proteins and transcription factors, as were surgical specimens from an esthesioneuroblastoma. Results Neuron-rich epithelium is always found inferior to the cribriform plate, even at advanced age, despite the interruptions in the neuroepithelial sheet caused by patchy respiratory metaplasia. The pattern of immunostaining with our antibody panel identifies two distinct types of basal cell progenitors in human OE similar to rodents. The panel also clarifies the complex composition of the esthesioneuroblastoma. Conclusion The extent of human olfactory mucosa at autopsy can easily be delineated as a function of age and neurological disease. The similarities in human vs. rodent OE will enable us to translate knowledge from experimental animals to humans and will extend our understanding of human olfactory pathophysiology. PMID:21792956

Cognitive impairment and olfactory panic from occupational exposure to VOCs.

PubMed

Reinhartz, Abe

2006-10-01

A Canadian government clerical worker in her early thirties developed frontal lobe dysfunction from inhalation of volatile organic compounds off-gassed during an office renovation. Pulmonary function, bronchial provocation, allergy testing, and a brain (SPECT) scan were performed. SPECT scanning showed frontotemporal hypoperfusion and neuropsychologic testing revealed deficits in verbal learning and poor organizational memory. A significant component of this worker's impairment was the development of "olfactory panic," a debilitating aversion to odor accompanied by symptoms of panic. The Ontario Workplace Safety and Insurance Appeals Tribunal granted entitlement for her cognitive difficulties and olfactory panic as a result of her toxic exposure.

Approaches for Assessing Olfaction in Children with Autism Spectrum Disorder.

PubMed

Kumazaki, Hirokazu; Okamoto, Masako; Kanzaki, Sho; Okada, Ken-Ichi; Mimura, Masaru; Minabe, Yoshio; Kikuchi, Mitsuru

2018-01-01

Olfactory traits in individuals with autism spectrum disorder (ASD) are considered the strongest predictors of social impairment. Compared to other sensory abnormalities, olfactory abnormalities in individuals with ASD are poorly understood. In this chapter, we provide an overview of the current assessment in individuals with ASD. Several confounding factors have to be considered when conducting research on olfaction in individuals with ASD. Qualitative measures of olfaction contain only limited information about the olfactory stimuli. In addition, little systematic information is available about individual's actual uses of olfaction in daily life. Only a limited number of experimental studies have performed quantitative measurements of olfactory abnormalities in ASD. Therefore, clarifying the relationship between olfactory traits and the influence of real-life situations in a laboratory setting is very difficult. Some new methodologies for measuring olfactory traits are gradually becoming available. New methods that reveal important links between ASD and olfactory traits should be developed in the future.

Comparison of odor identification among amnestic and non-amnestic mild cognitive impairment, subjective cognitive decline, and early Alzheimer's dementia.

PubMed

Park, Sung-Jin; Lee, Jee-Eun; Lee, Kwang-Soo; Kim, Joong-Seok

2018-03-01

Olfactory impairment might be an important clinical marker and predictor of Alzheimer's disease (AD). In the present study, we aimed to compare the degree of olfactory identification impairment in each mild cognitive impairment (MCI) subtype, subjective memory impairment, and early AD dementia and assessed the relationship between olfactory identification and cognitive performance. We consecutively included 50 patients with amnestic MCI, 28 patients with non-amnestic MCI, 20 patients with mild AD, and 17 patients with subjective memory impairment (SMI). All patients underwent clinical and neuropsychological assessments. A multiple choice olfactory identification cross-cultural smell identification test was also utilized. Controlling for age and gender, olfactory impairment was significantly more severe in patients with AD and amnestic MCI compared with the results from the non-amnestic MCI and SMI groups. Higher scores on MMSE, verbal and non-verbal memory, and frontal executive function tests were significantly related to olfactory identification ability. In conclusion, olfactory identification is impaired in amnestic MCI and AD. These findings are consistent with previous studies. In amnestic MCI patients, this dysfunction is considered to be caused by underlying AD pathology.

Correlation of dopaminergic terminal dysfunction and microstructural abnormalities of the basal ganglia and the olfactory tract in Parkinson's disease.

PubMed

Scherfler, Christoph; Esterhammer, Regina; Nocker, Michael; Mahlknecht, Philipp; Stockner, Heike; Warwitz, Boris; Spielberger, Sabine; Pinter, Bernadette; Donnemiller, Eveline; Decristoforo, Clemens; Virgolini, Irene; Schocke, Michael; Poewe, Werner; Seppi, Klaus

2013-10-01

Signal abnormalities of the substantia nigra and the olfactory tract detected either by diffusion tensor imaging, including measurements of mean diffusivity, a parameter of brain tissue integrity, and fractional anisotropy, a parameter of neuronal fibre integrity, or transcranial sonography, were recently reported in the early stages of Parkinson's disease. In this study, changes in the nigral and olfactory diffusion tensor signal, as well as nigral echogenicity, were correlated with clinical scales of motor disability, odour function and putaminal dopamine storage capacity measured with 6-[(18)F] fluorolevodopa positron emission tomography in early and advanced stages of Parkinson's disease. Diffusion tensor imaging, transcranial sonography and positron emission tomography were performed on 16 patients with Parkinson's disease (mean disease duration 3.7 ± 3.7 years, Hoehn and Yahr stage 1 to 4) and 14 age-matched healthy control subjects. Odour function was measured by the standardized Sniffin' Sticks Test. Mean putaminal 6-[(18)F] fluorolevodopa influx constant, mean nigral echogenicity, mean diffusivity and fractional anisotropy values of the substantia nigra and the olfactory tract were identified by region of interest analysis. When compared with the healthy control group, the Parkinson's disease group showed significant signal changes in the caudate and putamen by 6-[(18)F] fluorolevodopa positron emission tomography, in the substantia nigra by transcranial sonography, mean diffusivity and fractional anisotropy (P < 0.001, P < 0.01, P < 0.05, respectively) and in the olfactory tract by mean diffusivity (P < 0.05). Regional mean diffusivity values of the substantia nigra and the olfactory tract correlated significantly with putaminal 6-[(18)F] fluorolevodopa uptake (r = -0.52, P < 0.05 and r = -0.71, P < 0.01). Significant correlations were also found between nigral mean diffusivity values and the Unified Parkinson's Disease Rating Scale motor score (r = -0.48, P < 0.01) and between mean putaminal 6-[(18)F] fluorolevodopa uptake and the total odour score (r = 0.58; P < 0.05) as well as the Unified Parkinson's Disease Rating Scale motor score (r = -0.53, P < 0.05). This study reports a significant association between increased mean diffusivity signal and decreased 6-[(18)F] fluorolevodopa uptake, indicating that microstructural degradation of the substantia nigra and the olfactory tract parallels progression of putaminal dopaminergic dysfunction in Parkinson's disease. Since increases in nigral mean diffusivity signal also correlated with motor dysfunction, diffusion tensor imaging may serve as a surrogate marker for disease progression in future studies of putative disease modifying therapies.

Olfactory identification and Stroop interference converge in schizophrenia.

PubMed Central

Purdon, S E

1998-01-01

OBJECTIVE: To test the discriminant validity of a model predicting a dissociation between measures of right and left frontal lobe function in people with schizophrenia. PARTICIPANTS: Twenty-one clinically stable outpatients with schizophrenia. INTERVENTIONS: Patients were administered the University of Pennsylvania Smell Identification Test (UPSIT), the Stroop Color-Word Test (Stroop), and the Positive and Negative Syndrome Scale (PANSS). OUTCOME MEASURES: Scores on these tests and relation among scores. RESULTS: There was a convergence of UPSII and Stroop interference scores consistent with a common cerebral basis for limitations in olfactory identification and inhibition of distraction. There was also a divergence of UPSIT and Stroop reading scores suggesting that the olfactory identification limitation is distinct from a general limitation of attention or a dysfunction of the left dorsolateral prefrontal cortex. Most notable was the 81% classification convergence between the UPSIT and Stroop incongruous colour naming scores compared with the near-random 57% classification convergence of the UPSIT and Stroop reading scores. CONCLUSIONS: These data are consistent with a right orbitofrontal dysfunction in a subgroup of patients with schizophrenia, although the involvement of mesial temporal structures in both tasks must be ruled out with further study. A multifactorial model depicting contributions from diverse cerebral structures is required to describe the pathophysiology of schizophrenia. Valid behavioural methods for classifying suspected subgroups of patients with particular cerebral dysfunction would be of value in the construction of this model. PMID:9595890

Olfactory Dysfunction as a Global Biomarker for Sniffing out Alzheimer's Disease: A Meta-Analysis.

PubMed

Kotecha, Alisha M; Corrêa, Angelo D C; Fisher, Kim M; Rushworth, Jo V

2018-04-13

Cases of Alzheimer's disease (AD) are rising exponentially due to increasing global life expectancy. There are approximately 50 million sufferers worldwide, with prevalence rising most rapidly in low-income countries such as Africa and Asia. There is currently no definite diagnosis of AD until after death, thus an early biomarker for AD is urgently required in order to administer timelier and more effective interventions. Olfactory dysfunction (problems with the sense of smell) is one of the earliest, preclinical symptoms observed in AD. Olfaction is a promising early biomarker for use worldwide as it is easy, cheap to measure, and not reliant on specialist clinicians or laboratory analysis. We carried out a meta-analysis to determine the credibility of olfaction in diagnosing AD in the preclinical stages, by comparing olfaction in healthy controls against AD patients and patients with mild cognitive impairment (MCI). Data from 10 articles were subjected to two comparative meta-analyses. In the case of AD, the results illustrated that the overall magnitude of effect size was more apparent, d = -1.63, 95% CI [-1.95, -1.31], in comparison to that of MCI, d = -0.81, 95% CI [-1.08, -0.55]. This shows that olfaction worsens progressively as patients progress from MCI to AD, highlighting the potential for olfactory dysfunction to identify AD in the preclinical stages prior to MCI.

Gray Matter Volume Reduction of Olfactory Cortices in Patients With Idiopathic Olfactory Loss

PubMed Central

Yao, Linyin; Pinto, Jayant Marian; Yi, Xiaoli; Li, Li; Peng, Peng

2014-01-01

Idiopathic olfactory loss (IOL) is a common olfactory disorder. Little is known about the pathophysiology of this disease. Previous studies demonstrated decreased olfactory bulb (OB) volume in IOL patients when compared with controls. The aim of our study was to investigate structural brain alterations in areas beyond the OB. We acquired T1-weighted magnetic resonance images from 16 patients with IOL and from 16 age- and sex-matched controls on a 3T scanner. Voxel-based morphometry (VBM) was performed using VBM8 toolbox and SPM8 in a Matlab environment. Psychophysical testing confirmed that patients had higher scores for Toyota and Takagi olfactometer and lower scores for Sniffin’ Sticks olfactory test than controls (t = 46.9, P < 0.001 and t = 21.4, P < 0.001, respectively), consistent with olfactory dysfunction. There was a significant negative correlation between the 2 olfactory tests (r = −0.6, P = 0.01). In a volume of interest analysis including primary and secondary olfactory areas, we found patients with IOL to exhibit gray matter volume loss in the orbitofrontal cortex, anterior cingulate cortex, insular cortex, parahippocampal cortex, and the piriform cortex. The present study indicates that changes in the central brain structures proximal to the OB occur in IOL. Further investigations of this phenomenon may be helpful to elucidate the etiology of IOL. PMID:25240014

Variables associated with olfactory disorders in adults: A U.S. population-based analysis.

PubMed

Noel, Julia; Habib, Al-Rahim R; Thamboo, Andrew; Patel, Zara M

2017-03-01

Olfactory dysfunction is known to have significant social, psychological, and safety implications. Despite increasingly recognized prevalence, potential risk factors for olfactory loss have been arbitrarily documented and knowledge is limited in scale. The aim of this study is to identify potential demographic and exposure variables correlating with olfactory dysfunction. Cross-sectional analysis of the 2011-2012 and 2013-2014 editions of the National Health Examination and Nutrition Survey was performed. The utilized survey reports from a nationally representative sample of about 5000 persons each year located in counties across the United States. There is an interview and physical examination component which includes demographic, socioeconomic, dietary, and health-related questions as well as medical, dental, physiologic measurements, and laboratory tests. 3594 adult respondents from 2011 to 2012 and 3708 respondents from 2013 to 2014 were identified from the above population-based database. The frequency of self-reported disorders as well as performance on odor identification testing was determined in relation to demographic factors, occupational or environmental exposures, and urinary levels of environmental and industrial compounds. In both subjective and objective analysis, smell disorders were significantly more common with increasing age. While the non-Hispanic Black and non-Hispanic Asian populations were less likely to report subjective olfactory loss, they, along with Hispanics, performed more poorly on odor identification than Caucasians. Those with limited education had a decreased prevalence of hyposmia. Women outperformed men on smell testing. Those reporting exposure to vapors were more likely to experience olfactory dysfunction, and urinary levels of manganese, 2-Thioxothiazolidine-4-carboxylic acid, and 2-Aminothiazoline-4-carboxylic acid were lower among respondents with subjective smell disturbance. In odor detection, elevated serum levels of lead and urinary levels of 2,4 dichlorophenol were associated with anosmia and hyposmia, respectively. This study provides current, population-based data identifying demographic and exposure elements related to smell disturbances in U.S. adults. Age, race, gender, education, exposure to vapors, urinary levels of manganese, 2-Thioxothiazolidine-4-carboxylic acid, 2-Aminothiazoline-4-carboxylic acid, 2,4 dichlorophenol, and serum lead levels were all implicated in smell disturbance. Care should be taken in interpretation due to lack of consistency between subjective and objective measures of olfaction as well as limitations related to population-based data. Prospective trials are indicated to further elucidate these relationships.

Olfactory Functioning in First-Episode Psychosis.

PubMed

Kamath, Vidyulata; Lasutschinkow, Patricia; Ishizuka, Koko; Sawa, Akira

2018-04-06

Though olfactory deficits are well-documented in schizophrenia, fewer studies have examined olfactory performance profiles across the psychosis spectrum. The current study examined odor identification, discrimination, and detection threshold performance in first-episode psychosis (FEP) patients diagnosed with schizophrenia, schizoaffective disorder, bipolar disorder with psychotic features, major depression with psychotic features, and other psychotic conditions. FEP patients (n = 97) and healthy adults (n = 98) completed birhinal assessments of odor identification, discrimination, and detection threshold sensitivity for lyral and citralva. Participants also completed measures of anticipatory pleasure, anhedonia, and empathy. Differences in olfactory performances were assessed between FEP patients and controls and within FEP subgroups. Sex-stratified post hoc analyses were employed for a complete analysis of sex differences. Relationships between self-report measures and olfactory scores were also examined. Individuals with psychosis had poorer scores across all olfactory measures when compared to the control group. Within the psychosis cohort, patients with schizophrenia-associated psychosis had poorer odor identification, discrimination, and citralva detection threshold scores relative to controls. In schizophrenia patients, greater olfactory disturbance was associated with increased negative symptomatology, greater self-reported anhedonia, and lower self-reported anticipatory pleasure. Patients with mood-associated psychosis performed comparable to controls though men and women in this cohort showed differential olfactory profiles. These findings indicate that olfactory deficits extend beyond measures of odor identification in FEP with greater deficits observed in schizophrenia-related subgroups of psychosis. Studies examining whether greater olfactory dysfunction confers greater risk for developing schizophrenia relative to other forms of psychosis are warranted.

Olfactory function in chemical workers exposed to acrylate and methacrylate vapors.

PubMed Central

Schwartz, B S; Doty, R L; Monroe, C; Frye, R; Barker, S

1989-01-01

An investigation of the olfactory function of 731 workers at a chemical facility which manufacturers acrylates and methacrylates was undertaken using a standardized quantitative test. In a cross-sectional analysis of the data, no associations of chemical exposure with olfactory test scores were observed. A nested case-control study designed to evaluate the cumulative effects of exposure on olfactory function, however, revealed elevated crude exposure odds ratios (95% confidence interval) of 2.0 (1.1, 3.8) for all workers and 6.0 (1.7, 21.5) for workers who never smoked cigarettes. Logistic regression analysis, adjusting for multiple confounders, revealed exposure odds ratios of 2.8 (1.1, 7.0) and 13.5 (2.1, 87.6) in these same groups, respectively, and a dose-response relationship between olfactory dysfunction and cumulative exposure scores--semi-quantitative indices of lifetime exposure to the acrylates. The data also revealed decreasing exposure odds ratios with increasing duration since last exposure to these chemicals, suggesting that the effects may be reversible. PMID:2784947

Unirhinal Olfactory Testing for the Diagnostic Workup of Mild Cognitive Impairment.

PubMed

Huart, Caroline; Rombaux, Philippe; Gérard, Thomas; Hanseeuw, Bernard; Lhommel, Renaud; Quenon, Lisa; Ivanoiu, Adrian; Mouraux, André

2015-01-01

Olfactory dysfunction is associated with Alzheimer's disease (AD), and already present at pre-dementia stage. Based on the assumption that early neurodegeneration in AD is asymmetrical and that olfactory input is primarily processed in the ipsilateral hemisphere, we assessed whether unirhinal psychophysical and electrophysiological assessment of olfactory function can contribute to the diagnostic workup of mild cognitive impairment (MCI). Olfactory function of 13 MCI patients with positive amyloid PET, 13 aged-matched controls (AC) with negative amyloid PET and 13 patients with post-infectious olfactory loss (OD) was assessed unirhinally using (1) psychophysical testing of olfactory detection, discrimination and identification performance and (2) the recording of olfactory event-related brain potentials. Time-frequency analysis was used to enhance the signal-to-noise ratio of the electrophysiological responses. Psychophysical and electrophysiological assessment of auditory and trigeminal chemosensory function served as controls. As compared to AC and OD, MCI patients exhibited a significant asymmetry of olfactory performance. This asymmetry efficiently discriminated between MCI and AC (sensitivity: 85% , specificity: 77% ), as well as MCI and OD (sensitivity: 85% , specificity: 70% ). There was also an asymmetry of the electrophysiological responses, but not specific for MCI. In both MCI and OD, olfactory stimulation of the best nostril elicited significantly more activity than stimulation of the worse nostril, between 3-7.5 Hz and 1.2-2.0 s after stimulus onset. Trigeminal and auditory psychophysical testing did not show any difference between groups. MCI patients exhibit a marked asymmetry of behavioral olfactory function, which could be useful for the diagnostic workup of MCI.

The effect of olfactory training on the odor threshold in patients with traumatic anosmia.

PubMed

Jiang, Rong-San; Twu, Chih-Wen; Liang, Kai-Li

2017-09-01

Olfactory training is a novel intervention that has been used to treat olfactory dysfunction. This study attempted to investigate the effect of olfactory training in patients with traumatic anosmia. Patients with a clear history of anosmia after experiencing a head injury and whose phenyl ethyl alcohol (PEA) odor detection thresholds were -1 after steroid and zinc treatment were included. The patients were randomly divided into two groups, with patients in one group given a bottle of PEA and those in another group given a bottle of mineral oil for 3-month olfactory training. All the patients were followed up with a PEA threshold test and the traditional Chinese version of the University of Pennsylvania Smell Identification Test (UPSIT-TC). Magnetic resonance imaging was performed to measure the volume of the olfactory bulbs. Any patient whose PEA threshold result was below -1.01 or whose UPSIT-TC score increased four or more points was considered to have shown improvement in their olfactory function. Forty-two patients received PEA olfactory training, whereas 39 received olfactory training with mineral oil. The improvement of PEA thresholds function was observed in 10 patients within the PEA group and in 2 patients in the mineral oil group. The frequency of improvement of threshold within the PEA group was significantly higher than that of the mineral oil group. Neither olfactory bulb volume nor UPSIT-TC score was significantly different between the two groups. Our results showed that olfactory training with PEA can improve PEA odor threshold levels in patients with traumatic anosmia.

Olfaction

PubMed Central

Pinto1, Jayant M.

2011-01-01

Olfaction represents an ancient, evolutionarily critical physiologic system. In humans, chemosensation mediates safety, nutrition, sensation of pleasure, and general well-being. Factors that affect human olfaction included structural aspects of the nasal cavity that can modulate airflow and therefore odorant access to the olfactory cleft, and inflammatory disease, which can affect both airflow as well as olfactory nerve function. After signals are generated, olfactory information is processed and coded in the olfactory bulb and disseminated to several areas in the brain. The discovery of olfactory receptors by Axel and Buck sparked greater understanding of the molecular basis of olfaction. However, the precise mechanisms used by this system are still under great scrutiny due to the complexity of understanding how an enormous number of chemically diverse odorant molecules are coded into signals understood by the brain. Additionally, it has been challenging to dissect olfactory sensation due to the multiple areas of areas of the brain that receive and modulate this information. Consequently, our knowledge of olfactory dysfunction in humans remains primitive. Aging represents the major cause of loss of smell, although a number of clinical and environmental factors are thought to affect chemosensory function. Treatment options focus on reducing sinonasal inflammation when present, ruling out other treatable causes, and counseling patients on safety measures. PMID:21364221

Extended version of the "Sniffin' Sticks" identification test: test-retest reliability and validity.

PubMed

Sorokowska, A; Albrecht, E; Haehner, A; Hummel, T

2015-03-30

The extended, 32-item version of the Sniffin' Sticks identification test was developed in order to create a precise tool enabling repeated, longitudinal testing of individual olfactory subfunctions. Odors of the previous test version had to be changed for technical reasons, and the odor identification test needed re-investigation in terms of reliability, validity, and normative values. In our study we investigated olfactory abilities of a group of 100 patients with olfactory dysfunction and 100 controls. We reconfirmed the high test-retest reliability of the extended version of the Sniffin' Sticks identification test and high correlations between the new and the original part of this tool. In addition, we confirmed the validity of the test as it discriminated clearly between controls and patients with olfactory loss. The additional set of 16 odor identification sticks can be either included in the current olfactory test, thus creating a more detailed diagnosis tool, or it can be used separately, enabling to follow olfactory function over time. Additionally, the normative values presented in our paper might provide useful guidelines for interpretation of the extended identification test results. The revised version of the Sniffin' Sticks 32-item odor identification test is a reliable and valid tool for the assessment of olfactory function. Copyright © 2015 Elsevier B.V. All rights reserved.

The effect of non-diabetic chronic renal failure on olfactory function.

PubMed

Koseoglu, S; Derin, S; Huddam, B; Sahan, M

2017-05-01

In chronic renal failure (CRF), deterioration of glomerular filtration results in accumulation of metabolites in the body which affect all organs. This study was performed to investigate the olfactory functions, and determine if hemodialysis or peritoneal dialysis improves olfactory function in non-diabetic CRF patients. The olfactory functions were analyzed in CRF patients not on a dialysis program and had a creatinine level≥2mg/dL, in CRF patients on hemodialysis or peritoneal dialysis, and in healthy controls. Diabetic patients were excluded since diabetes alone is a cause of olfactory dysfunction. The study group consisted of a total of 107 individuals including 38CRF patients on a hemodialysis program, 15 CRF patients on peritoneal dialysis, 30 patients with a creatinine level ≥ 2mg/dL without any need for dialysis, and 24 healthy controls with normal renal functions. Olfactory functions were analyzed with "Sniffin' sticks" test, and the groups were compared for the test results. All test parameters were impaired in patients with CRF. The median TDI scores of the patients with CRF and the healthy subjects were 24.75 (13-36) and 32.5 (27.75-37.75), respectively, with a statistically significant difference in between (P<0.001). The olfactory functions for the dialysis patients were better than those for the CRF patients not on a dialysis program (P=0.020). Non-diabetic CRF affects olfactory functions negatively. Dialysis improves olfactory functions in those patients. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Hyposmia: an underestimated and frequent adverse effect of chemotherapy.

PubMed

Riga, Maria; Chelis, Leonidas; Papazi, Theano; Danielides, Vasilios; Katotomichelakis, Michael; Kakolyris, Stylianos

2015-10-01

Optimal function of both the olfactory sensory neurons and the olfactory mucosa is a prerequisite for normal olfactory perception. Both the olfactory neurons and mucosa might be subjects to the neurotoxic and mucotoxic effects of chemotherapy. Despite the recognized importance of olfaction in nutrition and quality of life, the potential olfactory toxicity of chemotherapy regimens has not been adequately assessed. The aim of this study is to investigate whether mucotoxic and/or neurotoxic drugs compromise olfactory performance. Forty-four consecutive patients completed the "Sniffin' Sticks" test, an objective quantitative/qualitative method to assess olfactory function, at diagnosis and immediately before the infusion of the last session of three to four chemotherapy cycles, according to the therapeutic protocol. The patients underwent therapy containing oxaliplatin and antimetabolites (5-FU or capecitabine; O+A group), taxanes and platinum analogues (cisplatin and carboplatin; T+P group), or taxanes and anthracyclines (doxorubicin or liposomal doxorubicin; T+A group). A significant decrease was noted for olfactory threshold (OT), olfactory discrimination (OD), olfactory identification (OI), and the composite threshold-discrimination-identification (TDI) score. A significant deterioration of all olfactory indices was found for each chemotherapy group. Pairwise comparisons revealed significant differences between the O+A and the T+P group regarding OT and TDI. TDI scores were significantly lower after chemotherapy in all age groups. Patients older than 50 years were found to be more susceptible to olfactory toxicity than younger patients. Patients who undergo chemotherapy experience significant compromise in their olfactory function. A grading system for olfactory toxicity is proposed.

Risk of decline and chance of improvement in olfaction among patients with post-traumatic olfactory loss.

PubMed

Kuo, C-L; Shu, C-H

2015-12-01

To evaluate the chance of improvement and risk of decline in olfaction among patients with post-traumatic olfactory loss. This study comprised 80 patients. Changes in olfaction were determined using a visual analogue scale and the 'Sniffin' Sticks' test. Logistic regression was used to identify predictors for olfactory changes. Olfactory changes were observed in 9-35 per cent of patients. The rates of improvement and decline according to visual analogue scale scores were 35 per cent and 10 per cent respectively, whereas those in the Sniffin' Sticks test were 9 per cent and 11 per cent respectively. There was a predictive link between non-anosmia and decline in Sniffin' Sticks test scores (odds ratio = 16.61, p = 0.003). A positive correlation was observed between the scores in the first and last examinations (rho = 0.532, p < 0.001). Patients should be informed that they may experience an improvement or decline in olfaction following post-traumatic olfactory dysfunction. This study provides evidence to support comprehensive counselling regarding prognosis as an integral part of management strategies.

Distinct amyloid precursor protein processing machineries of the olfactory system.

PubMed

Kim, Jae Yeon; Rasheed, Ameer; Yoo, Seung-Jun; Kim, So Yeun; Cho, Bongki; Son, Gowoon; Yu, Seong-Woon; Chang, Keun-A; Suh, Yoo-Hun; Moon, Cheil

2018-01-01

Processing of amyloid precursor protein (APP) occurs through sequential cleavages first by β-secretase and then by the γ-secretase complex. However, abnormal processing of APP leads to excessive production of β-amyloid (Aβ) in the central nervous system (CNS), an event which is regarded as a primary cause of Alzheimer's disease (AD). In particular, gene mutations of the γ-secretase complex-which contains presenilin 1 or 2 as the catalytic core-could trigger marked Aβ accumulation. Olfactory dysfunction usually occurs before the onset of typical AD-related symptoms (eg, memory loss or muscle retardation), suggesting that the olfactory system may be one of the most vulnerable regions to AD. To date however, little is known about why the olfactory system is affected so early by AD prior to other regions. Thus, we examined the distribution of secretases and levels of APP processing in the olfactory system under either healthy or pathological conditions. Here, we show that the olfactory system has distinct APP processing machineries. In particular, we identified higher expressions levels and activity of γ-secretase in the olfactory epithelium (OE) than other regions of the brain. Moreover, APP c-terminal fragments (CTF) are markedly detected. During AD progression, we note increased expression of presenilin2 of γ-secretases in the OE, not in the OB, and show that neurotoxic Aβ*56 accumulates more quickly in the OE. Taken together, these results suggest that the olfactory system has distinct APP processing machineries under healthy and pathological conditions. This finding may provide a crucial understanding of the unique APP-processing mechanisms in the olfactory system, and further highlights the correlation between olfactory deficits and AD symptoms. Copyright © 2017 Elsevier Inc. All rights reserved.

The influence of olfactory loss on dietary behaviors.

PubMed

Aschenbrenner, Katja; Hummel, Cornelia; Teszmer, Katja; Krone, Franziska; Ishimaru, Tadashi; Seo, Han-Seok; Hummel, Thomas

2008-01-01

To assess dietary behavior and possible changes in food selection in patients with smell loss. A total of 176 patients (114 women and 62 men) age 17 to 86 years were classified into three diagnostic groups (normosmia, n = 12; hyposmia, n = 75; functional anosmia, n = 89) according to their olfactory test scores obtained with "Sniffin' Sticks." Group differences in food intake and dietary behaviors were investigated with a specifically designed questionnaire providing a dietary alterations score (DAS). Numerous dietary changes were reported, e.g., 29% of all patients reported that they eat less since the onset of olfactory dysfunction, 39% use more spices with their food, 47% go out to eat at restaurants less frequently, 37% eat less sweets, and 48% drink less sweet beverages. Subjects with weight gain or weight loss scored higher on the DAS scale than subjects who did not report changes in weight. Similarly, DAS scale changes were more pronounced in subjects with a gradual onset of olfactory loss compared to subjects with a sudden loss of olfaction. Finally, a change of taste preferences toward savory and salty foods was observed across all patients enrolled in the present study. Patients with olfactory loss report alterations of dietary behaviors. Numerous factors appear to impact the results of olfactory loss in terms of changes in diet.

Toxic effects of inhaled manganese on the olfactory bulb: an ultrastructural approach in mice.

PubMed

Colin-Barenque, L; Souza-Gallardo, L M; Fortoul, T I

2011-01-01

Olfactory dysfunction is a common symptom reported by patients with neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Despite the knowledge gathered about the pathology of these diseases, little information has been generated regarding the ultrastructure modifications of the granule cells that regulate the information for odor identification. Swollen organelles and nuclear invaginations identified the exposed mice. Necrosis was evidenced at 4th week of exposure, whereas apoptosis arose at 8th week of exposure. A ruffled electron-dense membrane changes were also found. The changes observed could be explained by the reactive oxygen species generated by manganese and its effects on the membrane's structure and on the cytoskeleton's function. This study contributes to correlate metal air pollution and neurodegenerative changes with olfactory affection.

Phenomenal and access consciousness in olfaction.

PubMed

Stevenson, Richard J

2009-12-01

Contemporary literature on consciousness, with some exceptions, rarely considers the olfactory system. In this article the characteristics of olfactory consciousness, viewed from the standpoint of the phenomenal (P)/access (A) distinction, are examined relative to the major senses. The review details several qualitative differences in both olfactory P consciousness (shifts in the felt location, universal synesthesia-like and affect-rich experiences, and misperceptions) and A consciousness (recovery from habituation, capacity for conscious processing, access to semantic and episodic memory, learning, attention, and in the serial-unitary nature of olfactory percepts). The basis for these differences is argued to arise from the functions that the olfactory system performs and from the unique neural architecture needed to instantiate them. These data suggest, at a minimum, that P and A consciousness are uniquely configured in olfaction and an argument can be made that the P and A distinction may not hold for this sensory system.

OLFACTORY DYSFUNCTION IN PARKINSON’S DISEASE: POSITIVE EFFECT OF CIGARETTE SMOKING

PubMed Central

Sharer, James D.; Leon-Sarmiento, Fidias E.; Morley, James F.; Weintraub, Daniel; Doty, Richard L.

2014-01-01

Background There is compelling evidence from over 60 epidemiological studies that smoking significantly reduces the risk of Parkinson’s disease (PD). In general, those who currently smoke cigarettes, as well as those with a past history of such smoking, have a reduced risk of PD compared to those who have never smoked. Recently it has been suggested that a cardinal non-motor sensory symptom of PD, olfactory dysfunction, may be less severe in PD patients who smoke than in PD patients who do not, in contrast to the negative effect of smoking on olfaction described in the general population. Methods We evaluated University of Pennsylvania Smell Identification Test (UPSIT) scores from 323 Parkinson’s patients and 323 controls closely matched individually on age, sex, and smoking history (never, past, current). Results The patients exhibited much lower UPSIT scores than did the controls (P<0.0001). The relative decline in dysfunction of the current PD smokers was less than that of the never- and past-PD smokers (respective Ps=0.0005 & 0.0019). The female PD patients outperformed their male counterparts by a larger margin than did the female controls (3.66 vs. 1.07 UPSIT points; respective Ps < 0.0001 & 0.06). Age-related declines in UPSIT scores were generally present (P < 0.0001). No association between the olfactory measure and smoking dose, as indexed by pack years, was evident. Conclusions PD patients who currently smoke do not exhibit the smoking-related decline in olfaction observed in non-PD control subjects who currently smoke. The physiologic basis of this phenomenon is yet to be defined. PMID:25545729

Possible link between Toxoplasma gondii and the anosmia associated with neurodegenerative diseases.

PubMed

Prandota, Joseph

2014-05-01

Toxoplasma gondii is an intracellular protozoan infecting 30% to 50% of global human population. Recently, it was suggested that chronic latent neuroinflammation caused by the parasite may be responsible for the development of several neurodegenerative diseases manifesting with the loss of smell. Studies in animals inoculated with the parasite revealed cysts in various regions of the brain, including olfactory bulb. Development of behavioral changes was paralleled by the preferential persistence of cysts in defined anatomic structures of the brain, depending on the host, strain of the parasite, its virulence, and route of inoculation. Olfactory dysfunction reported in Alzheimer's disease, multiple sclerosis, and schizophrenia was frequently associated with the significantly increased serum anti-T gondii immunoglobulin G antibody levels. Damage of the olfactory system may be also at least in part responsible for the development of depression because T gondii infection worsened mood in such patients, and the olfactory bulbectomized rat serves as a model of depression.

Estimation of sensitivity and specificity of brain magnetic resonance imaging and single photon emission computed tomography in the diagnosis of olfactory dysfunction after head traumas.

PubMed

Atighechi, Saeid; Zolfaghari, Aliasghar; Baradaranfar, Mohammadhossein; Dadgarnia, Mohammadhossein

2013-01-01

Olfactory dysfunction has an incidence of 5-10% after head injury. Several objective and subjective tests had been proposed. Recent studies showed that brain single photon emission computed tomography (SPECT) and brain magnetic resonance imaging (MRI) have good diagnostic value in this era in which the most common sites of involvement were olfactory bulb and olfactory nerve in MRI and frontal lobe in SPECT. This study aimed to estimate the sensitivity and specificity of brain MRI and brain SPECT in the diagnosis of traumatic hyposmia and anosmia. From February 2009 to March 2011, 63 patients with head injury and smell complaint were selected for this study. Using an identification test and a threshold smell test, 28 were anosmic and 27 had hyposmia and the remaining 8 were normosmic. All of them underwent brain MRI and SPECT. The sensitivity of SPECT was 81.5 and 85.7% in hyposmia and anosmia, respectively. Its specificity was 87.5% in anosmia and 87.7% in anosmia. MRI sensitivity was 66.7% in hyposmia but 82.1% in anosmia. Its specificity was 85.7% in anosmia and 87.7% in anosmia. If MRI and SPECT were considered together, the sensitivity was 92.3% in hyposmia and 92% in anosmia, but the specificity was 87% in both cases. According to our study, both brain MRI and SPECT have high sensitivity and specificity in the diagnosis of traumatic anosmia, although brain SPECT is slightly superior to MRI. If the two techniques are applied together, the accuracy will be increased.

Anosmia-A Clinical Review.

PubMed

Boesveldt, Sanne; Postma, Elbrich M; Boak, Duncan; Welge-Luessen, Antje; Schöpf, Veronika; Mainland, Joel D; Martens, Jeffrey; Ngai, John; Duffy, Valerie B

2017-09-01

Anosmia and hyposmia, the inability or decreased ability to smell, is estimated to afflict 3-20% of the population. Risk of olfactory dysfunction increases with old age and may also result from chronic sinonasal diseases, severe head trauma, and upper respiratory infections, or neurodegenerative diseases. These disorders impair the ability to sense warning odors in foods and the environment, as well as hinder the quality of life related to social interactions, eating, and feelings of well-being. This article reports and extends on a clinical update commencing at the 2016 Association for Chemoreception Sciences annual meeting. Included were reports from: a patient perspective on losing the sense of smell with information on Fifth Sense, a nonprofit advocacy organization for patients with olfactory disorders; an otolaryngologist's review of clinical evaluation, diagnosis, and management/treatment of anosmia; and researchers' review of recent advances in potential anosmia treatments from fundamental science, in animal, cellular, or genetic models. As limited evidence-based treatments exist for anosmia, dissemination of information on anosmia-related health risks is needed. This could include feasible and useful screening measures for olfactory dysfunction, appropriate clinical evaluation, and patient counseling to avoid harm as well as manage health and quality of life with anosmia. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Sensory Disruption in Modern Living and the Emergence of Sensory Inequities

PubMed Central

Hoover, Kara C.

2018-01-01

Modern lifestyles are disrupting the human senses—primarily sight, sound, and smell. Noise-induced hearing loss has been noted for centuries and increasing over time following the industrial era. From the mid-20th century, the numbers of individuals with myopia (the leading visual impairment) have been increasing globally. Historical evidence for olfactory dysfunction is not known but its etiological links to pollution suggest it increased following industrialization. Clinical interventions for sight and sound loss include preventative and corrective measures but none exist for olfactory dysfunction. Further, olfactory loss is linked to multiple negative health outcomes across physical, mental, and social domains. Due to the global rates of exposure to pollution, olfaction is a global health concern. The environmental injustice inherent in human society (locally and globally) results in inequitable risk for sensory loss by the most vulnerable populations and creates an even deeper gradient in health disparity. Situated within the environmental justice and health disparity literature, this paper introduces the term sensory inequity to describe variation in sensory environments based on socio-economic status (which is often entwined with race and education). A key challenge to risk management is awareness of sensory inequity experienced by vulnerable populations and incorporating that awareness into basic research and policy. PMID:29599658

Dietary intakes of fats, fish and nuts and olfactory impairment in older adults.

PubMed

Gopinath, Bamini; Sue, Carolyn M; Flood, Victoria M; Burlutsky, George; Mitchell, Paul

2015-07-01

It is unclear whether lifestyle modifications, such as dietary changes, should be advocated to prevent olfactory dysfunction. We investigated the association between dietary intakes of fats (saturated, mono-unsaturated and polyunsaturated fats, and cholesterol) and related food groups (nuts, fish, butter, margarine) with olfactory impairment. There were 1331 and 667 participants (older than 60 years) at baseline and 5-year follow-up, respectively, with complete olfaction and dietary data. Dietary data were collected using a validated semi-quantitative FFQ. Olfaction was measured using the San Diego Odor Identification Test. In a cross-sectional analysis of baseline data, those in the highest v. lowest quartile of n-6 PUFA intake had reduced odds of having any olfactory impairment, multivariable-adjusted OR 0.66 (95% CI 0.44, 0.97), P for trend = 0.06. Participants in the highest v. lowest quartile of margarine consumption had a 65% reduced odds of having moderate/severe olfactory impairment (P for trend = 0.02). Participants in the highest quartile compared to the lowest quartile (reference) of nut consumption had a 46% (P for trend = 0.01) and 58% (P for trend = 0.001) reduced odds of having any or mild olfactory impairment, respectively. Older adults in the highest v. lowest quartile of fish consumption had 35% (P for trend = 0.03) and 50% (P for trend = 0.01) reduced likelihood of having any or mild olfactory impairment, respectively. In longitudinal analyses, a marginally significant association was observed between nut consumption and incidence of any olfactory impairment, highest v. lowest quartile of nut consumption: OR 0.61 (95% CI 0.37, 1.00). Older adults with the highest consumption of nuts and fish had reduced odds of olfactory impairment, independent of potential confounding variables.

Olfactory Function is Associated with Cognitive Performance: Results of the Heinz Nixdorf Recall Study.

PubMed

Tebrügge, Sarah; Winkler, Angela; Gerards, Diana; Weimar, Christian; Moebus, Susanne; Jöckel, Karl-Heinz; Erbel, Raimund; Jokisch, Martha

2018-01-01

There is strong evidence for an association of olfactory dysfunction and neurodegenerative diseases. Studies on the association of olfaction and cognition in the general population are rare. To evaluate gender- and age-specific associations of olfactory function and cognitive performance in a well characterized population-based study sample. At the third examination of the Heinz Nixdorf Recall study (n = 3,087), 2,640 participants (48% men; 68.2±7.2 years) underwent Sniffin' Sticks Screening Test measuring olfactory function on a scale of 0-12 points. Olfactory function was rated as anosmic, hyposmic, or normosmic (≤6, 7-10 or ≥11 points, respectively). All participants performed eight validated cognitive subtests. Age- (55-64 years, 65-74 years, 75-86 years) and gender-stratified multivariate analysis of covariance was used to evaluate group differences in cognitive performance. Women showed better olfactory function than men (p < 0.001). For middle-aged participants, olfactory groups differed in almost all cognitive subtests. The analyses revealed no gender effects, although associations were slightly greater for women than for men. Anosmics showed the worst cognitive performance and normosmics showed the best cognitive performance. In the young- and old-aged groups, a quantitative association was found for anosmics in all subtests and for normosmics and hyposmics in almost all subtests. This is the first study reporting on age-specific associations of olfactory function and cognitive performance in the general population. The association found in middle-aged participants (65-74 years) may serve as a marker to improve identification of persons at high risk for cognitive decline and dementia.

Clinical and histologic studies of olfactory outcomes after nasoseptal flap harvesting.

PubMed

Kim, Sang-Wook; Park, Kyung Bum; Khalmuratova, Roza; Lee, Hong-Kyoung; Jeon, Sea-Yuong; Kim, Dae Woo

2013-07-01

Since the introduction of an endonasal endoscopic approach in transsphenoidal pituitary surgery, reports of perioperative olfactory changes have presented conflicting results. We examined the incidence of olfactory loss in cases of endoscopic transsphenoidal pituitary surgery with skull base repair using the nasoseptal flap (NSF) and the effects of monopolar electrocautery commonly used in designing the NSF. Case-control study. Fifteen patients who underwent endoscopic transsphenoidal pituitary surgery with skull base reconstruction using the NSF were divided into cold knife (n = 8) and electrocautery (n = 7) groups according to the device used in the superior incision of the NSF. Patients were followed regularly to monitor the need for dressing or adhesiolysis around the olfactory cleft. All subjects received olfactory tests before and 6 months after surgery. Septal mucosa specimens obtained during posterior septectomy were incised with different devices, and the degree of mucosal damage was evaluated. One patient in the electrocautery group demonstrated olfactory dysfunction postoperatively, but the other 14 patients showed no decrease in olfaction. In histologic analyses, 55.8% and 76.9% of the mucosal surface showed total epithelial loss when the mucosa was cut with cutting- and coagulation-mode electrocautery, respectively. In contrast, only 20% of the mucosal surface exhibited total epithelial loss when the mucosa was cut with a cold knife (P < .01). Olfactory impairment is not common after use of the NSF. Use of the cold knife in making superior incision may reduce tissue damage with better olfactory outcomes. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

Prenatal cocaine exposure impairs selective attention: evidence from serial reversal and extradimensional shift tasks.

PubMed

Garavan, H; Morgan, R E; Mactutus, C F; Levitsky, D A; Booze, R M; Strupp, B J

2000-08-01

This study assessed the effects of prenatal cocaine exposure on cognitive functioning, using an intravenous (IV) rodent model that closely mimics the pharmacokinetics seen in humans after smoking or IV injection and that avoids maternal stress and undernutrition. Cocaine-exposed males were significantly impaired on a 3-choice, but not 2-choice, olfactory serial reversal learning task. Both male and female cocaine-exposed rats were significantly impaired on extradimensional shift tasks that required shifting from olfactory to spatial cues; however, they showed no impairment when required to shift from spatial to olfactory cues. In-depth analyses of discrete learning phases implicated deficient selective attention as the basis of impairment in both tasks. These data provide clear evidence that prenatal cocaine exposure produces long-lasting cognitive dysfunction, but they also underscore the specificity of the impairment.

History of smoking and olfaction in Parkinson's disease.

PubMed

Lucassen, Elisabeth B; Sterling, Nicholas W; Lee, Eun-Young; Chen, Honglei; Lewis, Mechelle M; Kong, Lan; Huang, Xuemei

2014-07-01

Olfactory dysfunction is the most common pre-motor symptom in Parkinson's disease (PD), and smoking is known to be associated with lower risk of PD. This study tested the hypothesis that smoking is associated with better olfaction in PD. Smoking history was obtained from 76 PD subjects (22 with a history of smoking [smokers], 54 who never smoked [nonsmokers]), and 70 controls (17 smokers, 53 nonsmokers). Olfaction was assessed using the 40-item University of Pennsylvania Smell Identification Test (UPSIT). The olfactory scores between groups and subgroups were compared using analysis of covariance with adjustment for age, gender, and monoamine oxidase B (MAO-B) inhibitor usage. Overall the olfactory score was lower in PD compared with controls (olfactory scores: 21.5 vs. 33.5, P < 0.0001). Among controls, there was no significant difference in olfaction between smokers and nonsmokers (olfactory scores, 33.2 vs. 34.2; P = 0.95). Among PD subjects, however, smokers scored significantly better regarding olfaction compared with nonsmokers (olfactory scores: 24.4 vs. 19.9, P = 0.02). These data suggest that a history of smoking is associated with better olfaction among PD patients. The finding may be related to why smoking may be protective against PD. Further studies are needed to confirm this finding and investigate the underlying mechanisms. © 2014 International Parkinson and Movement Disorder Society.

Analysis of chemosensory function in patients with chronic Eustachian tube dysfunction prior to and after balloon dilatation.

PubMed

Ute, Walliczek-Dworschak; Lisa, Schmierer; Brandon, Greene; Robert, Pellegrino; Philipp, Dworschak; Stuck, Boris Alexander; Christian, Güldner

2018-10-01

Eustachian tube dysfunction (ETD) affects approximately 1% of adults in the general population. Non treated Eustachian tube dysfunction can result in chronic middle ear diseases, which have been shown to significantly affect taste sensitivity. A promising treatment is balloon dilatation of the Eustachian tube. The primary aim of the present study was to investigate whether individuals with ETD had impairment in chemosensory functions, and the changes of the chemosensory function after balloon dilatation of the Eustachian tube. 26 patients (17 female, 9 male) (=56 ears) suffering from ETD with a mean age of 39±15years were included in the present study. 20 patients (76%) returned to be evaluated at the follow up (=40 ears) 51±22days after balloon dilatation. For pre- and post operation, gustatory function was measured with a lateralized gustatory test with the taste strips and olfactory function was tested by means of the Sniffin' Sticks test battery (threshold, discrimination and identification (ID)). Patients' baseline taste function (summed taste score 9.8±3.5 (mean±SD)) was significantly impaired compared to normative data (summed taste score 12.4±2.3; p=0.002). After balloon dilatation of the Eustachian tube, the taste function remained stable (summed taste score 9.4±4.3; p=0.814). Olfactory function (odor ID, summed score (TDI)) improved postoperatively (TDI 32.4±3.6) compared to pre-operative scores (TDI 33.6±4.0; p=0.012), but not to a clinically relevant extent. This study suggests, that patients suffering from ETD exhibit reduced taste scores. Balloon dilatation of the Eustachian tube does not seem to influence gustatory function, but olfactory function showed improvement. Copyright © 2018 Elsevier B.V. All rights reserved.

Improvement of Olfactory Function With High Frequency Non-invasive Auricular Electrostimulation in Healthy Humans

PubMed Central

Maharjan, Ashim; Wang, Eunice; Peng, Mei; Cakmak, Yusuf O.

2018-01-01

In past literature on animal models, invasive vagal nerve stimulation using high frequencies has shown to be effective at modulating the activity of the olfactory bulb (OB). Recent advances in invasive vagal nerve stimulation in humans, despite previous findings in animal models, used low frequency stimulation and found no effect on the olfactory functioning. The present article aimed to test potential effects of non-invasive, high and low frequency vagal nerve stimulation in humans, with supplementary exploration of the orbitofrontal cortex using near-infrared spectroscopy (NIRS). Healthy, male adult participants (n = 18) performed two olfactory tests [odor threshold test (OTT) and supra-threshold test (STT)] before and after receiving high-, low frequency vagal nerve stimulation and placebo (no stimulation). Participant's olfactory functioning was monitored using NIRS, and assessed with two behavioral olfactory tests. NIRS data of separate stimulation parameters were statistically analyzed using repeated-measures ANOVA across different stages. Data from olfactory tests were analyzed using paired parametric and non-parametric statistical tests. Only high frequency, non-invasive vagal nerve stimulation was able to positively modulate the performance of the healthy participants in the STT (p = 0.021, Wilcoxon sign-ranked test), with significant differences in NIRS (p = 0.014, post-hoc with Bonferroni correction) recordings of the right hemispheric, orbitofrontal cortex. The results from the current article implore further exploration of the neurocircuitry involved under vagal nerve stimulation and the effects of non-invasive, high frequency, vagal nerve stimulation toward olfactory dysfunction which showcase in Parkinson's and Alzheimer's Diseases. Despite the sufficient effect size (moderate effect, correlation coefficient (r): 0.39 for the STT) of the current study, future research should replicate the current findings with a larger cohort. PMID:29740266

Improvement of Olfactory Function With High Frequency Non-invasive Auricular Electrostimulation in Healthy Humans.

PubMed

Maharjan, Ashim; Wang, Eunice; Peng, Mei; Cakmak, Yusuf O

2018-01-01

In past literature on animal models, invasive vagal nerve stimulation using high frequencies has shown to be effective at modulating the activity of the olfactory bulb (OB). Recent advances in invasive vagal nerve stimulation in humans, despite previous findings in animal models, used low frequency stimulation and found no effect on the olfactory functioning. The present article aimed to test potential effects of non-invasive, high and low frequency vagal nerve stimulation in humans, with supplementary exploration of the orbitofrontal cortex using near-infrared spectroscopy (NIRS). Healthy, male adult participants ( n = 18) performed two olfactory tests [odor threshold test (OTT) and supra-threshold test (STT)] before and after receiving high-, low frequency vagal nerve stimulation and placebo (no stimulation). Participant's olfactory functioning was monitored using NIRS, and assessed with two behavioral olfactory tests. NIRS data of separate stimulation parameters were statistically analyzed using repeated-measures ANOVA across different stages. Data from olfactory tests were analyzed using paired parametric and non-parametric statistical tests. Only high frequency, non-invasive vagal nerve stimulation was able to positively modulate the performance of the healthy participants in the STT ( p = 0.021, Wilcoxon sign-ranked test), with significant differences in NIRS ( p = 0.014, post-hoc with Bonferroni correction ) recordings of the right hemispheric, orbitofrontal cortex. The results from the current article implore further exploration of the neurocircuitry involved under vagal nerve stimulation and the effects of non-invasive, high frequency, vagal nerve stimulation toward olfactory dysfunction which showcase in Parkinson's and Alzheimer's Diseases. Despite the sufficient effect size (moderate effect, correlation coefficient (r): 0.39 for the STT) of the current study, future research should replicate the current findings with a larger cohort.

Altered G Protein Coupling in Olfactory Neuroepithelial Cells From Patients With Schizophrenia

PubMed Central

Borgmann-Winter, Karin E.; Wang, Hoau-Yan; Ray, Rabindranath; Willis, Brooke R.; Moberg, Paul J.; Rawson, Nancy E.; Gur, Raquel E.; Turetsky, Bruce I.; Hahn, Chang-Gyu

2016-01-01

Increasing evidence suggests that olfactory dysfunction is an endophenotype of schizophrenia, and thus the olfactory system can be studied both in relation to this sensory dysfunction and also as a means of examining pathophysiologic mechanisms of schizophrenia. In this study, we examined human olfactory neuroepithelial (ON) biopsy tissues and their in vitro culture cells for ligand-induced guanine nucleotide-binding protein (G protein) activation and downstream signaling. We assessed the binding of a nonhydrolyzable GTP analogue [35S]GTPγS binding to specific G protein subtypes in response to odorants, dopamine, or serotonin in ON cell membranes from matched schizophrenia-control subjects. In response to odorant mixtures, we found decreased [35S]GTPγS binding to Gαs/olf in schizophrenia patients. These changes were not mediated by mRNA expression of key molecules of G protein coupling, including adenylate cyclase III (ACIII), protein kinase A (PKA), protein kinase Cγ (PKCγ), or Gαs or Gαolf in ON cells or ON biopsy tissues. In contrast, dopamine (DA)- and serotonin (5HT)-induced S35-GTPγS binding to Gαs/olf and Gαq/11 were significantly increased in schizophrenia cases, while these parameters were strikingly reduced by in vitro treatment with antipsychotics. Patients with schizophrenia exhibit increases in electrolfactogram (EOG) recordings, suggesting enhanced odorant-induced activation. Our results of decreased odorant-induced G protein activation may point further downstream for underlying mechanisms for increased EOG measures. Increased G protein activation in response to DA and 5HT may suggest increased postreceptor DA or 5HT signaling as an additional mechanism of dopaminergic or serotonergic dysregulation in schizophrenia. PMID:26373539

How much does nasal cavity morphology matter? Patterns and rates of olfactory airflow in phyllostomid bats

PubMed Central

Eiting, Thomas P.; Perot, J. Blair; Dumont, Elizabeth R.

2015-01-01

The morphology of the nasal cavity in mammals with a good sense of smell includes features that are thought to improve olfactory airflow, such as a dorsal conduit that delivers odours quickly to the olfactory mucosa, an enlarged olfactory recess at the back of the airway, and a clear separation of the olfactory and respiratory regions of the nose. The link between these features and having a good sense of smell has been established by functional examinations of a handful of distantly related mammalian species. In this paper, we provide the first detailed examination of olfactory airflow in a group of closely related species that nevertheless vary in their sense of smell. We study six species of phyllostomid bats that have different airway morphologies and foraging ecologies, which have been linked to differences in olfactory ability or reliance. We hypothesize that differences in morphology correlate with differences in the patterns and rates of airflow, which in turn are consistent with dietary differences. To compare species, we make qualitative and quantitative comparisons of the patterns and rates of airflow through the olfactory region during both inhalation and exhalation across the six species. Contrary to our expectations, we find no clear differences among species in either the patterns of airflow through the airway or in rates of flow through the olfactory region. By and large, olfactory airflow seems to be conserved across species, suggesting that morphological differences appear to be driven by other mechanical demands on the snout, such as breathing and feeding. Olfactory ability may depend on other aspects of the system, such as the neurobiological processing of odours that work within the existing morphology imposed by other functional demands on the nasal cavity. PMID:25520358

Reduced Suprathreshold Odor Identification in Patients with Pseudotumor Cerebri: A Non-Randomized Prospective Study.

PubMed

Dotan, Gad; Cohen, Eyal; Klein, Ainat; Kesler, Anat

2018-01-01

Recent evidence suggests that olfaction is impaired in patients with pseudotumor cerebri (PTC). To measure suprathreshold olfactory function by using the University of Pennsylvania Smell Identification Test (UPSIT), assessing its usefulness for routine clinical use. Forty PTC patients underwent USPIT olfactory testing. Twenty-nine out of 40 (73%) PTC patients (36 women, 4 men; mean age 34 years) had reduced suprathreshold smell sensation according to UPSIT scores: 19 (47%) had mild microsmia, 9 (23%) had moderate microsmia, and one (3%) was classified as having severe microsmia. The mean UPSIT score of all patients was 32.4 (95% confidence interval 31.4-33.4). Multivariate regression analysis found that UPSIT scores were not related to disease activity, disease duration, initial intracranial pressure (ICP), or visual function. Many PTC patients have reduced suprathreshold olfactory dysfunction that can be discovered by UPSIT, a rapidly administered smell test, which is suitable for clinical office use.

Olfactory Deficit Detected by fMRI in Early Alzheimer’s Disease

PubMed Central

Wang, Jianli; Eslinger, Paul J.; Doty, Richard L.; Zimmerman, Erin K.; Grunfeld, Robert; Sun, Xiaoyu; Connor, James R.; Price, Joseph L.; Smith, Michael B.; Yang, Qing X.

2012-01-01

Alzheimer’s disease (AD) is accompanied by smell dysfunction, as measured by psychophysical tests. Currently it is unknown whether AD-related alterations in central olfactory system neural activity, as measured by functional magnetic resonance imaging (fMRI), are detectable beyond those observed in healthy elderly. Moreover, it is not known whether such changes are correlated with indices of odor perception and dementia. To investigate these issues, twelve early stage AD patients and thirteen non-demented controls underwent fMRI while being exposed to each of three concentrations of lavender oil odorant. All participants were administered the University of Pennsylvania Smell Identification Test (UPSIT), the Mini-Mental State Examination (MMSE), the Mattis Dementia Rating Scale-2 (DRS-2), and the Clinical Dementia Rating Scale (CDR). The Blood oxygen level-dependent (BOLD) signal at primary olfactory cortex (POC) was weaker in AD than in HC subjects. At the lowest odorant concentration, the BOLD signals within POC, hippocampus, and insula were significantly correlated with UPSIT, MMSE, DRS-2, and CDR scores. The BOLD signal intensity and activation volume within the POC increased significantly as a function of odorant concentration in the AD group, but not in the control group. These findings demonstrate that olfactory fMRI is sensitive to the AD-related olfactory and functional cognitive decline. PMID:20709038

Olfactory Transcriptional Analysis of Salmon Exposed to Mixtures of Chlorpyrifos and Malathion Reveal Novel Molecular Pathways of Neurobehavioral Injury

PubMed Central

Wang, Lu; Espinoza, Herbert M.; MacDonald, James W.; Bammler, Theo K.; Williams, Chase R.; Yeh, Andrew; Louie, Ke’ale W.; Marcinek, David J.; Gallagher, Evan P.

2016-01-01

Pacific salmon exposed to sublethal concentrations of organophosphate pesticides (OP) have impaired olfactory function that can lead to loss of behaviors that are essential for survival. These exposures often involve mixtures and can occur at levels below those which inhibit acetylcholinesterase (AChE). In this study, juvenile Coho salmon were exposed for 24 h to either 0.1, 0.5, or 2.5 ppb chlorpyrifos (CPF), 2, 10, or 50 ppb malathion (MAL), or binary mixtures of 0.1 CPF:2 ppb MAL, 0.5 CPF:10 ppb MAL, or 2.5 CPF:10 ppb MAL to mimic single and binary environmental exposures. Microarray analysis of olfactory rosettes from pesticide-exposed salmon revealed differentially expressed genes involved in nervous system function and signaling, aryl hydrocarbon receptor signaling, xenobiotic metabolism, and mitochondrial dysfunction. Coho exposed to OP mixtures exhibited a more pronounced loss in detection of a predatory olfactory cue relative to those exposed to single compounds, whereas respirometry experiments demonstrated that exposure to OPs, individually and in mixtures, reduced maximum respiratory capacity of olfactory rosette mitochondria. The observed molecular, biochemical, and behavioral effects occurred largely in the absence of effects on brain AChE. In summary, our results provide new insights associated with the sublethal neurotoxic effects of OP mixtures relevant to environmental exposures involving molecular and cellular pathways of injury to the salmon olfactory system that underlie neurobehavioral injury. PMID:26494550

A Qualitative Organic Analysis that Exploits the Senses of Smell, Touch, and Sound

ERIC Educational Resources Information Center

Bromfield-Lee, Deborah C.; Oliver-Hoyo, Maria T.

2007-01-01

This laboratory experiment utilizes the characteristic aromas of some functional groups to exploit the sense of smell as a discriminating tool in an organic qualitative analysis scheme. Students differentiate a variety of compounds by their aromas and based on their olfactory classification identify an unknown functional group. Students then…

Smell in cystic fibrosis.

PubMed

Lindig, J; Steger, C; Beiersdorf, N; Michl, R; Beck, J F; Hummel, T; Mainz, J G

2013-03-01

In cystic fibrosis (CF), the most frequent life threatening inherited disease in Caucasians, sinonasal mucosa is regularly affected by defective mucociliary clearance. This facilitates pathogen colonization into CF airways and causes frequent symptoms of rhinosinusitis, including an impaired sense of smell. Despite probable effects on nutrition and overall health, CF-rhinosinusitis is little understood: CF-associated smelling deficiencies reported in literature vary between 12 and 71 %. The aim of this study was to assess olfactory and gustatory function in relation to sinonasal symptoms and sinonasal colonization, and lung function and nutrition. Thirty-five CF patients of different ages were compared to 35 age-matched healthy controls. Olfactory function was assessed by 'Sniffin'Sticks', gustatory qualities by "Taste-strips", and symptoms by sino-nasal outcome test 20 (SNOT-20). Normosmia was found in 62.8 % of healthy controls but only in 28.6 % of CF patients. In contrast the majority of CF patients exhibited a smell loss; almost 62.9 % of them were hyposmic, and 8.6 % functionally anosmic. Importantly, reduced olfactory function only affected odor thresholds, which were significantly increased in CF, not odor identification. This suggests that the olfactory dysfunction in CF results from the olfactory periphery due to either problems in conduction and/or a functional lesion due to the inflammatory process. SNOT-20 scores increased continuously from normosmic to hyposmic and anosmic CF patients (means 7.2/11.1/28.3 points). Neither sinonasal pathogen colonization, gender, pulmonary function, nor allergy or sinonasal surgery appeared to have significant effects on olfactory function and taste. Olfactory disorders are considerably more frequent in CF patients than in age-matched healthy controls. Assessing these parameters within CF-routine care should be considered because of their importance to nutrition and, thus, overall therapy outcome.

Anosmia and olfactory outcomes following paediatric traumatic brain injury.

PubMed

Bakker, Kathleen; Catroppa, Cathy; Anderson, Vicki

2016-01-01

Research into olfactory dysfunction (OD) following paediatric traumatic brain injury (TBI) is limited. The current study investigated the frequency of OD following paediatric TBI and the relationship between OD and injury characteristics including severity, site of impact and cause of injury. It was hypothesized that children with moderate/severe TBI would demonstrate greater OD than those with mild TBI. Thirty-seven children aged 8-16 with TBI were recruited to a prospective longitudinal study at a metropolitan children's hospital. Olfactory assessment, using the University of Pennsylvania Smell Identification Test, was completed at 0-3 months post-injury. Nineteen per cent of participants demonstrated impaired olfaction, while a small number (5%) were anosmic. A significant relationship between OD and severity of injury was found. No other injury variables demonstrated a significant relationship with olfactory outcomes. OD was relatively common in this paediatric TBI cohort and the hypothesized relationship with severity of injury was supported. It is recommended that information about OD after TBI be routinely provided to children and families. Further research is needed in larger cohorts to support the implementation of routine clinical assessment, understand the relationship between OD and other injury characteristics, determine the functional implications of OD and document recovery trajectories.

PACS-1 Mediates Phosphorylation-Dependent Ciliary Trafficking of the CNG Channel in Olfactory Sensory Neurons

PubMed Central

Jenkins, Paul M.; Zhang, Lian; Thomas, Gary; Martens, Jeffrey R.

2009-01-01

Impaired ciliary protein transport in olfactory sensory neurons (OSNs) leads to anosmia, and is a newly recognized clinical manifestation of a class of human disorders called ciliopathies. Surprisingly little is known regarding the mechanisms controlling trafficking to this unique neuronal compartment. Here, we show a novel role for phosphofurin acidic cluster-sorting protein 1 (PACS-1) in the ciliary trafficking of the olfactory CNG channel. PACS-1 is an intracellular sorting protein that mediates its effects through the binding of acidic clusters on cargo protein. This interaction is dependent on CK2 phosphorylation of both PACS-1 and its cargo. We show that CNGB1b contains two putative PACS-1 binding sites, which are phosphorylated by the serine/threonine protein kinase, CK2. Additionally, we show that PACS-1 is expressed in OSNs and interacts in complex with the CNG channel. CK2 inhibition in native OSNs causes a loss of CNG channel from cilia and subsequent olfactory dysfunction, while adenoviral expression of mutant PACS-1 causes similar mislocalization. These results provide a mechanism for the subunit-dependent ciliary trafficking of the CNG channel and offer insight into the mechanisms of ciliary transport. PMID:19710307

PACS-1 mediates phosphorylation-dependent ciliary trafficking of the cyclic-nucleotide-gated channel in olfactory sensory neurons.

PubMed

Jenkins, Paul M; Zhang, Lian; Thomas, Gary; Martens, Jeffrey R

2009-08-26

Impaired ciliary protein transport in olfactory sensory neurons (OSNs) leads to anosmia, and is a newly recognized clinical manifestation of a class of human disorders called ciliopathies. Surprisingly little is known regarding the mechanisms controlling trafficking to this unique neuronal compartment. Here, we show a novel role for phosphofurin acidic cluster-sorting protein 1 (PACS-1) in the ciliary trafficking of the olfactory cyclic-nucleotide-gated (CNG) channel. PACS-1 is an intracellular sorting protein that mediates its effects through the binding of acidic clusters on cargo protein. This interaction is dependent on CK2 phosphorylation of both PACS-1 and its cargo. We show that CNGB1b contains two putative PACS-1 binding sites, which are phosphorylated by the serine/threonine protein kinase, CK2. Additionally, we show that PACS-1 is expressed in OSNs and interacts in complex with the CNG channel. CK2 inhibition in native OSNs causes a loss of CNG channel from cilia and subsequent olfactory dysfunction, while adenoviral expression of mutant PACS-1 causes similar mislocalization. These results provide a mechanism for the subunit-dependent ciliary trafficking of the CNG channel and offer insight into the mechanisms of ciliary transport.

Olfactory bulb and olfactory sulcus depths are associated with disease duration and attack frequency in multiple sclerosis patients.

PubMed

Tanik, Nermin; Serin, Halil Ibrahim; Celikbilek, Asuman; Inan, Levent Ertugrul; Gundogdu, Fatma

2015-11-15

Multiple sclerosis (MS) is a neuroinflammatory and neurodegenerative disease that progresses to axonal loss and demyelinization. Olfactory dysfunction in patients with MS has been reported frequently. We were interested in the associations of olfactory bulb (OB) and olfactory sulcus depth (OSD) with disease duration and attack frequency. We included 25 patients with MS and 30 age- and sex-matched controls in this study. The Expanded Disability Status Scale, Beck Depression Inventory, and Mini Mental State Examination were applied. OB, OSD, and magnetic resonance imaging plaque numbers were calculated. OB volume and OSD in patients with MS were significantly lower than those in the control group (right and left OB: p<0.001; right OSD: p=0.001; and left OSD: p=0.039). Disease duration was negatively correlated with right and left OB volume (right OB: r=-0.434, p=0.030 and left OB: r=-0.518, p=0.008). Attack frequency was negatively correlated with left OB volume and left OSD (left OB: r=-0.428, p=0.033 and left OSD: r=-0.431, p=0.032). The OB and OSD were atrophied significantly in patients with MS, and this was correlated with disease duration and attack frequency. The left side tended to be dominant. Copyright © 2015 Elsevier B.V. All rights reserved.

Apolipoprotein E4 causes early olfactory network abnormalities and short-term olfactory memory impairments.

PubMed

Peng, Katherine Y; Mathews, Paul M; Levy, Efrat; Wilson, Donald A

2017-02-20

While apolipoprotein (Apo) E4 is linked to increased incidence of Alzheimer's disease (AD), there is growing evidence that it plays a role in functional brain irregularities that are independent of AD pathology. However, ApoE4-driven functional differences within olfactory processing regions have yet to be examined. Utilizing knock-in mice humanized to ApoE4 versus the more common ApoE3, we examined a simple olfactory perceptual memory that relies on the transfer of information from the olfactory bulb (OB) to the piriform cortex (PCX), the primary cortical region involved in higher order olfaction. In addition, we have recorded in vivo resting and odor-evoked local field potentials (LPF) from both brain regions and measured corresponding odor response magnitudes in anesthetized young (6-month-old) and middle-aged (12-month-old) ApoE mice. Young ApoE4 compared to ApoE3 mice exhibited a behavioral olfactory deficit coinciding with hyperactive odor-evoked response magnitudes within the OB that were not observed in older ApoE4 mice. Meanwhile, middle-aged ApoE4 compared to ApoE3 mice exhibited heightened response magnitudes in the PCX without a corresponding olfactory deficit, suggesting a shift with aging in ApoE4-driven effects from OB to PCX. Interestingly, the increased ApoE4-specific response in the PCX at middle-age was primarily due to a dampening of baseline spontaneous activity rather than an increase in evoked response power. Our findings indicate that early ApoE4-driven olfactory memory impairments and OB network abnormalities may be a precursor to later network dysfunction in the PCX, a region that not only is targeted early in AD, but may be selectively vulnerable to ApoE4 genotype. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

(-)Epigallocatechin-3-gallate prevents the reserpine-induced impairment of short-term social memory in rats.

PubMed

Tseng, Hsiang-Chien; Wang, Mao-Hsien; Soung, Hung-Sheng; Chang, Yi; Chang, Kuo-Chi

2015-12-01

Reserpine has been confirmed to induce cognitive dysfunction and increase brain neural oxidative stress. Green tea catechins, particularly (-)epigallocatechin-3-gallate (EGCG), have strong antioxidative properties and can protect against numerous oxidative damages. In this study, we examined the possible protective effects of EGCG on reserpine-induced impairment of short-term memory in rats. Reserpine (1 mg/kg, intraperitoneal)-induced memory impairment was assessed using the social recognition task method; locomotor activity and the olfactory discrimination ability were not altered as measured by an open-field test and an olfactory discrimination test, respectively. EGCG treatment (100 and 300 mg/kg, intraperitoneal, for 7 days, starting 6 days before the reserpine injection) could improve the worsened social memory of reserpine-treated rats. Also, EGCG treatment reduced reserpine-induced lipid peroxidation and enhanced the antioxidation power in the hippocampi of reserpine-treated rats. These results suggest a protective effect of EGCG in treating reserpine-induced impairment of memory, most probably through its powerful antioxidative activities. Accordingly, EGCG may hold a clinically relevant value in preventing reserpine-induced cognitive dysfunction.

Impact of the Usher syndrome on olfaction.

PubMed

Jansen, Fabian; Kalbe, Benjamin; Scholz, Paul; Mikosz, Marta; Wunderlich, Kirsten A; Kurtenbach, Stefan; Nagel-Wolfrum, Kerstin; Wolfrum, Uwe; Hatt, Hanns; Osterloh, Sabrina

2016-02-01

Usher syndrome is a genetically and clinically heterogeneous disease in humans, characterized by sensorineural hearing loss, retinitis pigmentosa and vestibular dysfunction. This disease is caused by mutations in genes encoding proteins that form complex networks in different cellular compartments. Currently, it remains unclear whether the Usher proteins also form networks within the olfactory epithelium (OE). Here, we describe Usher gene expression at the mRNA and protein level in the OE of mice and showed interactions between these proteins and olfactory signaling proteins. Additionally, we analyzed the odor sensitivity of different Usher syndrome mouse models using electro-olfactogram recordings and monitored significant changes in the odor detection capabilities in mice expressing mutant Usher proteins. Furthermore, we observed changes in the expression of signaling proteins that might compensate for the Usher protein deficiency. In summary, this study provides novel insights into the presence and purpose of the Usher proteins in olfactory signal transduction. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The interaction of working memory and emotion in persons clinically at risk for psychosis: an fMRI pilot study.

PubMed

Pauly, Katharina; Seiferth, Nina Y; Kellermann, Thilo; Ruhrmann, Stephan; Daumann, Bianca; Backes, Volker; Klosterkötter, Joachim; Shah, N Jon; Schneider, Frank; Kircher, Tilo T; Habel, Ute

2010-07-01

Subtle emotional and cognitive dysfunctions may already be apparent in individuals at risk for psychosis. However, there is a paucity of research on the neural correlates of the interaction of both domains. It remains unclear whether those correlates are already dysfunctional before a transition to psychosis. We used functional magnetic resonance imaging to examine the interaction of working memory and emotion in 12 persons clinically at high risk for psychosis (CHR) and 12 healthy subjects individually matched for age, gender and parental education. Participants performed an n-back task while negative or neutral emotion was induced by olfactory stimulation. Although healthy and psychosis-prone subjects did not differ in their working memory performance or the evaluation of the induced emotion, decreased activations were found in CHR subjects in the superior parietal lobe and the precuneus during working memory and in the insula during emotion induction. Looking at the interaction, CHR subjects, showed decreased activation in the right superior temporal gyrus, which correlated negatively with psychopathological scores. Decreased activation was also found in the thalamus. However, an increase of activation emerged in several cerebellar regions. Dysfunctions in areas associated with controlling whether incoming information is linked to emotional content and in the integration of multimodal information might lead to compensatory activations of cerebellar regions known to be involved in olfactory and working memory processes. Our study underlines that cerebral dysfunctions related to cognitive and emotional processes, as well as their interaction, can emerge in persons with CHR, even in absence of behavioral differences. (c) 2009 Elsevier B.V. All rights reserved.

Manifestations of Parkinson disease differ in association with REM sleep behavior disorder.

PubMed

Postuma, Ronald B; Gagnon, Jean-Francois; Vendette, Melanie; Charland, Katia; Montplaisir, Jacques

2008-09-15

REM sleep behavior disorder (RBD) is commonly associated with Parkinson disease (PD), but it is unclear whether this association has implications for disease manifestations. We evaluated 36 PD patients for the presence of RBD by polysomnography. Patients underwent an extensive evaluation by a movement disorders specialist blinded to polysomnography results. Severity of motor manifestations, autonomic, visual, psychiatric, and olfactory dysfunctions and quality of life (QOL) were assessed, and compared using regression analysis that adjusted for disease duration, age and sex. Severity of motor manifestations did not differ between groups. However, the presence of RBD in PD was strongly associated with symptoms and signs of orthostatic hypotension (systolic blood pressure lying to standing = -25.7 +/- 13.0 mmHg vs. -4.9 +/-14.1, P < 0.001); and orthostatic symptom prevalence = 71% vs. 27%, P = 0.0076). There was no association between RBD and other autonomic symptoms. Color vision was worse in patients with RBD, but olfactory dysfunction did not differ between groups. The prevalence of depression, hallucinations, paranoia, and impulse disorders did not differ between groups. Emotional functioning and general health QOL measures were lower in those with RBD, but there were no differences between groups on disease-specific indices or on measures of overall physical QOL. These findings suggest that the pathophysiology of RBD and nonmotor manifestations of PD, particularly autonomic dysfunction, are linked. (c) 2007 Movement Disorder Society.

Estradiol prevents olfactory dysfunction induced by A-β 25–35 injection in hippocampus

PubMed Central

2013-01-01

Background Some neurodegenerative diseases, such as Alzheimer and Parkinson, present an olfactory impairment in early stages, and sometimes even before the clinical symptoms begin. In this study, we assess the role of CA1 hippocampus (structure highly affected in Alzheimer disease) subfield in the rats’ olfactory behavior, and the neuroprotective effect of 17 beta estradiol (E2) against the oxidative stress produced by the injection of amyloid beta 25–35. Results 162 Wistar rats were ovariectomized and two weeks after injected with 2 μl of amyloid beta 25–35 (A-β25–35) in CA1 subfield. Olfactory behavior was evaluated with a social recognition test, odor discrimination, and search tests. Oxidative stress was evaluated with FOX assay and Western Blot against 4-HNE, Fluoro Jade staining was made to quantify degenerated neurons; all these evaluations were performed 24 h, 8 or 15 days after A-β25–35 injection. Three additional groups treated with 17 beta estradiol (E2) were also evaluated. The injection of A-β25–35 produced an olfactory impairment 24 h and 8 days after, whereas a partial recovery of the olfactory behavior was observed at 15 days. A complete prevention of the olfactory impairment was observed with the administration of E2 two weeks before the amyloid injection (A-β25–35 24 h + E2) and one or two weeks after (groups 8 A-β +E2 and 15 A-β +E2 days, respectively); a decrease of the oxidative stress and neurodegeneration were also observed. Conclusions Our finding shows that CA1 hippocampus subfield plays an important role in the olfactory behavior of the rat. The oxidative stress generated by the administration of A-β25–35 is enough to produce an olfactory impairment. This can be prevented with the administration of E2 before and after amyloid injection. This suggests a possible therapeutic use of estradiol in Alzheimer’s disease. PMID:24059981

[Reliability and validity analysis of simplified Chinese version of QOL questionnaire of olfactory disorders].

PubMed

Jin, X F; Wang, J; Li, Y J; Liu, J F; Ni, D F

2016-09-20

Objective: To cross-culturally translate the questionnaire of olfactory disorders(QOD)into a simplified Chinese version, and evaluate its reliability and validity in clinical. Method: A simplified Chinese version of the QOD was evaluated in test-retest reliability, split-half reliability and internal consistency.Then it was evaluated in validity test including content validity, criterion-related validity, responsibility. Criterion-related validity was using the medical outcome study's 36-item short rorm health survey(SF-36) and the World Health Organization quality of life-brief (WHOQOL-BREF) for comparison. Result: A total of 239 patients with olfactory dysfunction were enrolled and tested, in which 195 patients completed all three surveys(QOD, SF-36, WHOQOL-BREF). The test-retest reliabilities of the QOD-parosmia statements(QOD-P), QOD-quality of life(QOD-QoL), and the QOD-visual simulation(QOD-VAS)sections were 0.799( P <0.01),0.781( P <0.01),0.488( P <0.01), respectively, and the Cronbach' s α coefficients reliability were 0.477,0.812,0.889,respectively.The split-half reliability of QOD-QoL was 0.89. There was no correlation between the QOD-P section and the SF-36, but there were statistically significant correlations between the QOD-QoL and QOD-VAS sections with the SF-36. There was no correlation between the QOD-P section and the WHOQOL-BREF, but there were statistically significant correlations between the QOD-QoL and QOD-VAS sections with the SF-36 in most sections. Conclusion: The simplified Chinese version of the QOD was testified to be a reliable and valid questionnaire for evaluating patients with olfactory dysfunction living in mainland of China.The QOD-P section needs further modifications to properly adapt patients with Chinese cultural and knowledge background. Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.

Permanent anosmia and ageusia after resection of a left temporoinsular low-grade glioma: anatomofunctional considerations.

PubMed

Ribas, Eduardo Santamaria Carvalhal; Duffau, Hugues

2012-05-01

Five percent of the general population has olfactory or gustatory disorders, although most do not complain about it. However, in some cases, these symptoms can be disabling and may affect quality of life. Anosmia was reported as a possible complication following head injury and neurosurgical procedures, particularly after the resection of tumors located in the anterior fossa and the treatment of aneurysms in the anterior circulation. Nonetheless, in all of these situations, olfactory dysfunction could be explained by damage to the peripheral olfactory system. Here, the authors report a case of complete anosmia associated with ageusia following awake resection of a low-grade glioma involving the left temporoinsular region, with no recovery during a follow-up of 3 years. The frontal lobe was not retracted, and the olfactory tract was not visualized during surgery; therefore, postoperative anosmia and ageusia are likely explained by damage to the cortex and central pathways responsible for these senses. The authors suggest that the patient might have had a subclinical right hemianosmia before surgery, which is a common condition. After resection of the central structures critical for smell and taste processing in the left hemisphere, the patient could have finally had bilateral and complete olfactory and gustatory loss. This is the first known report of permanent anosmia and ageusia following glioma surgery. Because these symptoms might have been underestimated, more attention should be devoted to olfaction and taste, especially with regard to possible subclinical preoperative deficit.

Mice with genetic deletion of the heparin-binding growth factor midkine exhibit early preclinical features of Parkinson's disease.

PubMed

Prediger, Rui D S; Rojas-Mayorquin, Argelia E; Aguiar, Aderbal S; Chevarin, Caroline; Mongeau, Raymond; Hamon, Michel; Lanfumey, Laurence; Del Bel, Elaine; Muramatsu, Hisako; Courty, José; Raisman-Vozari, Rita

2011-08-01

There is considerable evidence showing that the neurodegenerative processes that lead to sporadic Parkinson's disease (PD) begin many years before the appearance of the characteristic motor symptoms and that impairments in olfactory, cognitive and motor functions are associated with time-dependent disruption of dopaminergic neurotransmission in different brain areas. Midkine is a 13-kDa retinoic acid-induced heparin-binding growth factor involved in many biological processes in the central nervous system such as cell migration, neurogenesis and tissue repair. The abnormal midkine expression may be associated with neurochemical dysfunction in the dopaminergic system and cognitive impairments in rodents. Here, we employed adult midkine knockout mice (Mdk(-/-)) to further investigate the relevance of midkine in dopaminergic neurotransmission and in olfactory, cognitive and motor functions. Mdk(/-) mice displayed pronounced impairments in their olfactory discrimination ability and short-term social recognition memory with no gross motor alterations. Moreover, the genetic deletion of midkine decreased the expression of the enzyme tyrosine hydroxylase in the substantia nigra reducing partially the levels of dopamine and its metabolites in the olfactory bulb and striatum of mice. These findings indicate that the genetic deletion of midkine causes a partial loss of dopaminergic neurons and depletion of dopamine, resulting in olfactory and memory deficits with no major motor impairments. Therefore, Mdk(-/-) mice may represent a promising animal model for the study of the early stages of PD and for testing new therapeutic strategies to restore sensorial and cognitive processes in PD.

Effects of Subthalamic Stimulation on Olfactory Function in Parkinson Disease.

PubMed

Cury, Rubens Gisbert; Carvalho, Margarete de Jesus; Lasteros, Fernando Jeyson Lopez; Dias, Alice Estevo; Dos Santos Ghilardi, Maria Gabriela; Paiva, Anderson Rodrigues Brandão; Coutinho, Artur Martins; Buchpiguel, Carlos Alberto; Teixeira, Manoel J; Barbosa, Egberto Reis; Fonoff, Erich Talamoni

2018-06-01

Olfactory dysfunction is a nonmotor symptom of Parkinson disease (PD) associated with reduction in quality of life. There is no evidence on whether improvements in olfaction after subthalamic deep brain stimulation (STN-DBS) may be directly attributable to motor improvement or whether this reflects a direct effect of DBS on olfactory brain areas. The aim of the present study was to evaluate the effect of DBS on olfactory function in PD, as well as to explore the correlation between these changes and changes in motor symptoms and brain metabolism. Thirty-two patients with PD were screened for STN-DBS. Patients were evaluated before and 1 year after surgery. Primary outcome was the change in olfactory function (Sniffin' Sticks odor-identification test [SST]) after surgery among the patients with hyposmia at baseline. Secondary outcomes included the relationship between motor outcomes and olfactory changes and [ 18 F]fluorodeoxyglucose-positron emission tomography analysis between subgroups with improvement versus no improvement of smell. STN-DBS improved SST after surgery (preoperative SST, median 7.3 ± 2.4 vs. postoperative SST, median 8.2 ± 2.1; P = 0.045) in a subset of patients among 29 of 32 patients who presented with hyposmia at baseline. The improvement in SST was correlated with DBS response (r = 0.424; P = 0.035). There was also an increase in glucose metabolism in the midbrain, cerebellum, and right frontal lobe in patients with SST improvement (P < 0.001). STN-DBS improves odor identification in a subset of patients with PD. Motor improvement together with changes in the brain metabolism may be linked to this improvement. Copyright © 2018 Elsevier Inc. All rights reserved.

Olfactory cleft computed tomography analysis and olfaction in chronic rhinosinusitis

PubMed Central

Kohli, Preeti; Schlosser, Rodney J.; Storck, Kristina

2016-01-01

Background: Volumetric analysis of the olfactory cleft by using computed tomography has been associated with olfaction in patients with chronic rhinosinusitis (CRS). However, existing studies have not comprehensively measured olfaction, and it thus remains unknown whether correlations differ across specific dimensions of odor perception. Objective: To use comprehensive measures of patient-reported and objective olfaction to evaluate the relationship between volumetric olfactory cleft opacification and olfaction. Methods: Olfaction in patients with CRS was evaluated by using “Sniffin' Sticks” tests and a modified version of the Questionnaire of Olfactory Disorders. Olfactory cleft opacification was quantified by using two- and three-dimensional, computerized volumetric analysis. Correlations between olfactory metrics and olfactory cleft opacification were then calculated. Results: The overall CRS cohort included 26 patients without nasal polyposis (CRSsNP) (68.4%) and 12 patients with nasal polyposis (CRSwNP) (31.6%). Across the entire cohort, total olfactory cleft opacification was 82.8%, with greater opacification in the CRSwNP subgroup compared with CRSsNP (92.3 versus 78.4%, p < 0.001). The percent total volume opacification correlated with the total Sniffin' Sticks score (r = −0.568, p < 0.001) as well as individual threshold, discrimination, and identification scores (p < 0.001 for all). Within the CRSwNP subgroup, threshold (r = −0.616, p = 0.033) and identification (r = −0.647, p = 0.023) remained highly correlated with total volume opacification. In patients with CRSsNP, the threshold correlated with total volume scores (r = −0.457, p = 0.019), with weaker and nonsignificant correlations for discrimination and identification. Correlations between total volume opacification and the Questionnaire of Olfactory Disorders were qualitatively similar to objective olfactory findings in both CRSwNP (r = −0.566, p = 0.070) and CRSsNP (r = −0.310, p = 0.141) subgroups, although neither reached significance. When examined by two-dimensional planes, the percent opacification of the anterior plane had the strongest correlations with objective olfaction. Conclusion: Olfactory cleft opacification correlated with objective measures of olfaction in patients with CRS, which correlated with threshold values in patients with CRSsNP and all dimensions of olfaction in those with CRSwNP. PMID:28124650

Olfaction in People with Down Syndrome: A Comprehensive Assessment across Four Decades of Age.

PubMed

Cecchini, Maria Paola; Viviani, Dario; Sandri, Marco; Hähner, Antje; Hummel, Thomas; Zancanaro, Carlo

2016-01-01

Down syndrome (DS) shows neuropathology similar to Alzheimer disease, which presents olfactory impairment. Previous work showed olfactory impairment in DS, but a comprehensive evaluation of olfactory function in DS is lacking. We investigated a large number (n = 56; M = 31, F = 25) DS participants (age range18-57y) using the "Sniffin' Sticks" Extended test. This comprises three subtests (threshold, discrimination, and identification) yielding a global score (TDI) defining normosmia, hyposmia, and functional anosmia. To the best of our knowledge, this is the second largest group of DS people investigated for olfactory function ever. Age- and sex matched euploid individuals (n = 53) were the control. In DS, TDI was lower (16.7±5.13 vs. 35.4±3.74; P<0.001), with DS people performing worse in any subtests (P<0.001 for all); 27 DS participants showed functional anosmia (i.e., TDI<16). In DS, age was weakly and negatively correlated with TDI (r = -0.28, P = 0.036) and identification (r = -0.34, P = 0.012). When participants were stratified in young adults (18-29y) and older adults (30-61y), a significant effect of age was found for identification in both DS (young adults, 8.3±2.58; older adults, 6.9±2.99; P = 0.031) and control (young-adult, 14.3±1.18, older adult, 13.0±1.54; P = 0.016). Olfactory function is overall severely impaired in DS people and may be globally impaired at relatively young age, despite of reportedly normal smell. However, specificity of this olfactory profile to DS should be considered with some caution because cognition was not evaluated in all DS participants and comparison with a control group of non-DS individuals having cognitive disabilities was lacking. Further study is required to longitudinally assess olfactory dysfunction in DS and to correlate it with brain pathology.

Olfaction in People with Down Syndrome: A Comprehensive Assessment across Four Decades of Age

PubMed Central

Cecchini, Maria Paola; Viviani, Dario; Sandri, Marco; Hähner, Antje; Hummel, Thomas; Zancanaro, Carlo

2016-01-01

Background Down syndrome (DS) shows neuropathology similar to Alzheimer disease, which presents olfactory impairment. Previous work showed olfactory impairment in DS, but a comprehensive evaluation of olfactory function in DS is lacking. Methods We investigated a large number (n = 56; M = 31, F = 25) DS participants (age range18-57y) using the “Sniffin’ Sticks” Extended test. This comprises three subtests (threshold, discrimination, and identification) yielding a global score (TDI) defining normosmia, hyposmia, and functional anosmia. To the best of our knowledge, this is the second largest group of DS people investigated for olfactory function ever. Age- and sex matched euploid individuals (n = 53) were the control. Results In DS, TDI was lower (16.7±5.13 vs. 35.4±3.74; P<0.001), with DS people performing worse in any subtests (P<0.001 for all); 27 DS participants showed functional anosmia (i.e., TDI<16). In DS, age was weakly and negatively correlated with TDI (r = -0.28, P = 0.036) and identification (r = -0.34, P = 0.012). When participants were stratified in young adults (18-29y) and older adults (30-61y), a significant effect of age was found for identification in both DS (young adults, 8.3±2.58; older adults, 6.9±2.99; P = 0.031) and control (young-adult, 14.3±1.18, older adult, 13.0±1.54; P = 0.016). Conclusion Olfactory function is overall severely impaired in DS people and may be globally impaired at relatively young age, despite of reportedly normal smell. However, specificity of this olfactory profile to DS should be considered with some caution because cognition was not evaluated in all DS participants and comparison with a control group of non-DS individuals having cognitive disabilities was lacking. Further study is required to longitudinally assess olfactory dysfunction in DS and to correlate it with brain pathology. PMID:26730728

Evaluation of olfaction and taste function in type 2 diabetic patients with and without peripheral neuropathy.

PubMed

Yazla, Semih; Özmen, Süay; Kıyıcı, Sinem; Yıldız, Demet; Haksever, Mehmet; Gencay, Sündüz

2018-03-01

Olfaction and gustation in patients with diabetes mellitus have great significance on quality of life, and their impairment may result in possible hazards. A limited number of studies have been performed to determine the alteration of both gustatory and olfactory function in type 2 diabetic patients with diabetic peripheral neuropathy (DPN). The aim of this study was to determine whether type 2 diabetic patients, with and without DPN, exhibit major olfactory and gustatory dysfunction using validated and dependable techniques. An observational-analytical case-control study was conducted. Sixty patients with type 2 diabetes mellitus (T2DM) and 30 healthy control subjects with a mean age of 57.1 ± 8.4 were included in the study. Patients with T2DM were recruited from the endocrinology outpatient clinic. After clinical evaluation and electromyography examination, patients with T2DM were divided into the 2 groups, with and without DPN. After a 10-hour fasting period, blood samples were taken for the measurement of serum creatinine, lipids, and HbA1c. For the quantitative assessment of olfactory function, all participants underwent butanol threshold test and odour identification test. Gustatory function was tested administering a whole-mouth above-threshold test using sucrose solutions. The control subjects showed significantly higher Sniffin' sticks and butanol threshold scores than the diabetic patients without DPN (P = .001 and P = .009). No significant difference was found in the gustatory function test between these 2 groups (P = .116). Diabetic patients with DPN had lower Sniffin' sticks scores, butanol threshold scores, and higher sucrose thresholds compared to the controls (P < .001, P < .001, and P = .002). There were no significant differences between diabetic patients with or without DPN regarding Sniffin' sticks scores, butanol threshold, and sucrose thresholds (P = .302, P = .181, and P = .118). In conclusion, this study demonstrates that T2DM is associated with olfactory and gustatory dysfunction. The fact that there was no difference between the diabetic patients with and without DPN elicits the idea of central neuropathy. This novel finding might facilitate the addition of olfactory and gustatory tests to the methodological spectrum of afferent pathway investigations. Copyright © 2017 John Wiley & Sons, Ltd.

Activity-Dependent Dysfunction in Visual and Olfactory Sensory Systems in Mouse Models of Down Syndrome

PubMed Central

Saqran, Lubna; Herrick, Scott P.; Frosch, Matthew P.; Hyman, Bradley T.

2017-01-01

Activity-dependent synaptic plasticity plays a critical role in the refinement of circuitry during postnatal development and may be disrupted in conditions that cause intellectual disability, such as Down syndrome (DS). To test this hypothesis, visual cortical plasticity was assessed in Ts65Dn mice that harbor a chromosomal duplication syntenic to human chromosome 21q. We find that Ts65Dn mice demonstrate a defect in ocular dominance plasticity (ODP) following monocular deprivation. This phenotype is similar to that of transgenic mice that express amyloid precursor protein (APP), which is duplicated in DS and in Ts65DN mice; however, normalizing APP gene copy number in Ts65Dn mice fails to rescue plasticity. Ts1Rhr mice harbor a duplication of the telomeric third of the Ts65Dn-duplicated sequence and demonstrate the same ODP defect, suggesting a gene or genes sufficient to drive the phenotype are located in that smaller duplication. In addition, we find that Ts65Dn mice demonstrate an abnormality in olfactory system connectivity, a defect in the refinement of connections to second-order neurons in the olfactory bulb. Ts1Rhr mice do not demonstrate a defect in glomerular refinement, suggesting that distinct genes or sets of genes underlie visual and olfactory system phenotypes. Importantly, these data suggest that developmental plasticity and connectivity are impaired in sensory systems in DS model mice, that such defects may contribute to functional impairment in DS, and that these phenotypes, present in male and female mice, provide novel means for examining the genetic and molecular bases for neurodevelopmental impairment in model mice in vivo. SIGNIFICANCE STATEMENT Our understanding of the basis for intellectual impairment in Down syndrome is hindered by the large number of genes duplicated in Trisomy 21 and a lack of understanding of the effect of disease pathology on the function of neural circuits in vivo. This work describes early postnatal developmental abnormalities in visual and olfactory sensory systems in Down syndrome model mice, which provide insight into defects in the function of neural circuits in vivo and provide an approach for exploring the genetic and molecular basis for impairment in the disease. In addition, these findings raise the possibility that basic dysfunction in primary sensory circuitry may illustrate mechanisms important for global learning and cognitive impairment in Down syndrome patients. PMID:28899917

Dysfunctional Incidental Olfaction in Mild Cognitive Impairment (MCI): An Electroencephalography (EEG) Study

PubMed Central

Walla, Peter; Duregger, Cornelia; Deecke, Lüder; Dal-Bianco, Peter

2011-01-01

Our study provides evidence that Mild Cognitive Impairment (MCI) is associated with olfactory dysfunction on both conscious and non-conscious levels. MCI patients and age-matched controls underwent a face processing task during which sympathy decisions had to be made via button presses. Incidentally, some of the faces were associated with a simultaneously presented odour. Although attention was paid to faces, brain activities were analysed with respect to odour versus no-odour conditions. Behavioural differences were found related to overall face recognition performance, but these were not statistically significant. However, odour-related neurophysiology differed between both groups. Normal controls demonstrated brain activity differences between odour and no-odour conditions that resemble difference activity patterns in healthy young participants as described in a previous magnetoencephalography (MEG) study [1]. They showed odour-related activity patterns between about 160 ms and 320 ms after stimulus onset and between about 640 ms and 720 ms. On the other hand, the patient group did not show any such difference activities. Based on previous research we interpret the early odour-related brain activity pattern in controls as being associated with subliminal olfaction and the later activity pattern with conscious olfaction. None of these were found in MCI patients, although it has to be emphasised that our sample size was rather small. We confirm previous findings about olfactory related dysfunction in patients with MCI and conclude from our findings that even subliminal odour-related information processing is impaired. PMID:24962612

Olfactory dysfunction and its measurement in the clinic and workplace.

PubMed

Doty, Richard L

2006-04-01

To provide an overview of practical means for quantitatively assessing the sense of smell in both the clinic and workplace. To address basic measurement issues, including those of test sensitivity, specificity, and reliability. To describe and discuss factors that influence olfactory function, including airborne toxins commonly found in industrial settings. Selective review and discussion. A number of well-validated practical threshold and suprathreshold tests are available for assessing smell function. The reliability, sensitivity, and specificity of such techniques vary, being influenced by such factors as test length and type. Numerous subject factors, including age, sex, health, medications, and exposure to environmental toxins, particularly heavy metals, influence the ability to smell. Modern advances in technology, in conjunction with better occupational medicine practices, now make it possible to reliably monitor and limit occupational exposures to hazardous chemicals and their potential adverse influences on the sense of smell. Quantitative olfactory testing is critical to establish the presence or absence of such adverse influences, as well as to (a) detect malingering, (b) establish disability compensation, and (c) monitor function over time.

In-situ recording of ionic currents in projection neurons and Kenyon cells in the olfactory pathway of the honeybee

PubMed Central

Rössler, Wolfgang

2018-01-01

The honeybee olfactory pathway comprises an intriguing pattern of convergence and divergence: ~60.000 olfactory sensory neurons (OSN) convey olfactory information on ~900 projection neurons (PN) in the antennal lobe (AL). To transmit this information reliably, PNs employ relatively high spiking frequencies with complex patterns. PNs project via a dual olfactory pathway to the mushroom bodies (MB). This pathway comprises the medial (m-ALT) and the lateral antennal lobe tract (l-ALT). PNs from both tracts transmit information from a wide range of similar odors, but with distinct differences in coding properties. In the MBs, PNs form synapses with many Kenyon cells (KC) that encode odors in a spatially and temporally sparse way. The transformation from complex information coding to sparse coding is a well-known phenomenon in insect olfactory coding. Intrinsic neuronal properties as well as GABAergic inhibition are thought to contribute to this change in odor representation. In the present study, we identified intrinsic neuronal properties promoting coding differences between PNs and KCs using in-situ patch-clamp recordings in the intact brain. We found very prominent K+ currents in KCs clearly differing from the PN currents. This suggests that odor coding differences between PNs and KCs may be caused by differences in their specific ion channel properties. Comparison of ionic currents of m- and l-ALT PNs did not reveal any differences at a qualitative level. PMID:29351552

Sex-specific effects of dehydroepiandrosterone (DHEA) on glucose metabolism in the CNS.

PubMed

Vieira-Marques, Claudia; Arbo, Bruno Dutra; Cozer, Aline Gonçalves; Hoefel, Ana Lúcia; Cecconello, Ana Lúcia; Zanini, Priscila; Niches, Gabriela; Kucharski, Luiz Carlos; Ribeiro, Maria Flávia M

2017-07-01

DHEA is a neuroactive steroid, due to its modulatory actions on the central nervous system (CNS). DHEA is able to regulate neurogenesis, neurotransmitter receptors and neuronal excitability, function, survival and metabolism. The levels of DHEA decrease gradually with advancing age, and this decline has been associated with age related neuronal dysfunction and degeneration, suggesting a neuroprotective effect of endogenous DHEA. There are significant sex differences in the pathophysiology, epidemiology and clinical manifestations of many neurological diseases. The aim of this study was to determine whether DHEA can alter glucose metabolism in different structures of the CNS from male and female rats, and if this effect is sex-specific. The results showed that DHEA decreased glucose uptake in some structures (cerebral cortex and olfactory bulb) in males, but did not affect glucose uptake in females. When compared, glucose uptake in males was higher than females. DHEA enhanced the glucose oxidation in both males (cerebral cortex, olfactory bulb, hippocampus and hypothalamus) and females (cerebral cortex and olfactory bulb), in a sex-dependent manner. In males, DHEA did not affect synthesis of glycogen, however, glycogen content was increased in the cerebral cortex and olfactory bulb. DHEA modulates glucose metabolism in a tissue-, dose- and sex-dependent manner to increase glucose oxidation, which could explain the previously described neuroprotective role of this hormone in some neurodegenerative diseases. Copyright © 2016. Published by Elsevier Ltd.

Low plasma tryptophan is associated with olfactory function in healthy elderly community dwellers in Japan.

PubMed

Adachi, Yusuke; Shimodaira, Yoshiki; Nakamura, Hidehiro; Imaizumi, Akira; Mori, Maiko; Kageyama, Yoko; Noguchi, Yasushi; Seki, Asuka; Okabe, Yuki; Miyake, Yuko; Ono, Kaori; Kumagai, Shu

2017-10-16

Decreased circulating tryptophan (Trp) levels are frequently observed in elderly patients with neurodegenerative disease including Alzheimer's disease. Trp may serve as a potential biomarker for monitoring disease risk in elderly people. We aimed to investigate the association between low plasma Trp levels and olfactory function, which is known to predict age-related diseases including dementia in elderly people. A total of 144 healthy elderly Japanese community (≥ 65 years old) dwellers from the Health, Aging and Nutritional Improvement study (HANI study) were the subjects of our analysis. Low Trp levels were classified using the lower limit values of the reference interval according to a previous report. Olfactory function was assessed using a card-type test called Open Essence, which includes 12 odour items that are familiar to Japanese people. The elderly subjects with low circulating Trp levels were compared to a control group with normal plasma Trp levels. We conducted the analyses using 144 people aged 65 years or older (mean age 73.7 ± 5.5 years; 36.1% men). The subjects showed normal serum albumin levels (4.4 ± 0.2 g/dL) and no daily living disabilities. Low plasma Trp levels (low Trp group) were found in 11.1% of the study population. The low Trp group showed a significantly lower correct-answer rate for the items india ink, perfume, curry and sweaty smelling socks than control group (P < 0.05). There was also a significant association between low Trp levels and low olfactory ability, after adjusting for age and sex. Lower plasma Trp levels were associated with a decrease in olfactory function in functionally competent older individuals. Because olfactory dysfunction predicts age-related diseases, low plasma Trp levels may represent a clinical sign of disease risk in elderly people.

Odor Landscapes in Turbulent Environments

NASA Astrophysics Data System (ADS)

Celani, Antonio; Villermaux, Emmanuel; Vergassola, Massimo

2014-10-01

The olfactory system of male moths is exquisitely sensitive to pheromones emitted by females and transported in the environment by atmospheric turbulence. Moths respond to minute amounts of pheromones, and their behavior is sensitive to the fine-scale structure of turbulent plumes where pheromone concentration is detectible. The signal of pheromone whiffs is qualitatively known to be intermittent, yet quantitative characterization of its statistical properties is lacking. This challenging fluid dynamics problem is also relevant for entomology, neurobiology, and the technological design of olfactory stimulators aimed at reproducing physiological odor signals in well-controlled laboratory conditions. Here, we develop a Lagrangian approach to the transport of pheromones by turbulent flows and exploit it to predict the statistics of odor detection during olfactory searches. The theory yields explicit probability distributions for the intensity and the duration of pheromone detections, as well as their spacing in time. Predictions are favorably tested by using numerical simulations, laboratory experiments, and field data for the atmospheric surface layer. The resulting signal of odor detections lends itself to implementation with state-of-the-art technologies and quantifies the amount and the type of information that male moths can exploit during olfactory searches.

Vanadium Exposure Induces Olfactory Dysfunction in an Animal Model of Metal Neurotoxicity

PubMed Central

Ngwa, Hilary Afeseh; Kanthasamy, Arthi; Jin, Huajun; Anantharam, Vellareddy; Kanthasamy, Anumantha G.

2014-01-01

Epidemiological evidence indicates chronic environmental exposure to transition metals may play a role in chronic neurodegenerative conditions such as Parkinson’s disease (PD). Chronic inhalation exposure to welding fumes containing metal mixtures may be associated with development of PD. A significant amount of vanadium is present in welding fumes, as vanadium pentoxide (V2O5), and incorporation of vanadium in the production of high strength steel has become more common. Despite the increased vanadium use in recent years, the neurotoxicological effects of this metal are not well characterized. Recently, we demonstrated that V2O5 induces dopaminergic neurotoxicity via protein kinase C delta (PKCδ)-dependent oxidative signaling mechanisms in dopaminergic neuronal cells. Since anosmia (inability to perceive odors) and non-motor deficits are considered to be early symptoms of neurological diseases, in the present study, we examined the effect of V2O5 on the olfactory bulb in animal models. To mimic the inhalation exposure, we intranasally administered C57 black mice a low-dose of 182 µg of V2O5 three times a week for one month, and behavioral, neurochemical and biochemical studies were performed. Our results revealed a significant decrease in olfactory bulb weights, tyrosine hydroxylase (TH) levels, levels of dopamine (DA) and its metabolite, 3, 4-dihydroxyphenylacetic acid (DOPAC) and increases in astroglia of the glomerular layer of the olfactory bulb in the treatment groups relative to vehicle controls. Neurochemical changes were accompanied by impaired olfaction and locomotion. These findings suggest that nasal exposure to V2O5 adversely affects olfactory bulbs, resulting in neurobehavioral and neurochemical impairments. These results expand our understanding of vanadium neurotoxicity in environmentally-linked neurological conditions. PMID:24362016

Urban air pollution: influences on olfactory function and pathology in exposed children and young adults.

PubMed

Calderón-Garcidueñas, Lilian; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Osnaya, Norma; González-Maciel, Angelica; Reynoso-Robles, Rafael; Villarreal-Calderon, Rafael; Herritt, Lou; Brooks, Diane; Keefe, Sheyla; Palacios-Moreno, Juan; Villarreal-Calderon, Rodolfo; Torres-Jardón, Ricardo; Medina-Cortina, Humberto; Delgado-Chávez, Ricardo; Aiello-Mora, Mario; Maronpot, Robert R; Doty, Richard L

2010-01-01

Mexico City (MC) residents are exposed to severe air pollution and exhibit olfactory bulb inflammation. We compared the olfactory function of individuals living under conditions of extreme air pollution to that of controls from a relatively clean environment and explore associations between olfaction scores, apolipoprotein E (APOE) status, and pollution exposure. The olfactory bulbs (OBs) of 35 MC and 9 controls 20.8+/-8.5 years were assessed by light and electron microscopy. The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 62 MC/25 controls 21.2+/-2.7 years. MC subjects had significantly lower UPSIT scores: 34.24+/-0.42 versus controls 35.76+/-0.40, p=0.03. Olfaction deficits were present in 35.5% MC and 12% of controls. MC APOE epsilon 4 carriers failed 2.4+/-0.54 items in the 10-item smell identification scale from the UPSIT related to Alzheimer's disease, while APOE 2/3 and 3/3 subjects failed 1.36+/-0.16 items, p=0.01. MC residents exhibited OB endothelial hyperplasia, neuronal accumulation of particles (2/35), and immunoreactivity to beta amyloid betaA(42) (29/35) and/or alpha-synuclein (4/35) in neurons, glial cells and/or blood vessels. Ultrafine particles were present in OBs endothelial cytoplasm and basement membranes. Control OBs were unremarkable. Air pollution exposure is associated with olfactory dysfunction and OB pathology, APOE 4 may confer greater susceptibility to such abnormalities, and ultrafine particles could play a key role in the OB pathology. This study contributes to our understanding of the influences of air pollution on olfaction and its potential contribution to neurodegeneration. Copyright 2009 Elsevier GmbH. All rights reserved.

Cholinergic modulation of dopaminergic neurons in the mouse olfactory bulb.

PubMed

Pignatelli, Angela; Belluzzi, Ottorino

2008-04-01

Considerable evidence exists for an extrinsic cholinergic influence in the maturation and function of the main olfactory bulb. In this study, we addressed the muscarinic modulation of dopaminergic neurons in this structure. We used different patch-clamp techniques to characterize the diverse roles of muscarinic agonists on identified dopaminergic neurons in a transgenic animal model expressing a reporter protein (green fluorescent protein) under the tyrosine hydroxylase promoter. Bath application of acetylcholine (1 mM) in slices and in enzymatically dissociated cells reduced the spontaneous firing of dopaminergic neurons recorded in cell-attached mode. In whole-cell configuration no effect of the agonist was observed, unless using the perforated patch technique, thus suggesting the involvement of a diffusible second messenger. The effect was mediated by metabotropic receptors as it was blocked by atropine and mimicked by the m2 agonist oxotremorine (10 muM). The reduction of periglomerular cell firing by muscarinic activation results from a membrane-potential hyperpolarization caused by activation of a potassium conductance. This modulation of dopaminergic interneurons may be important in the processing of sensory information and may be relevant to understand the mechanisms underlying the olfactory dysfunctions occurring in neurodegenerative diseases affecting the dopaminergic and/or cholinergic systems.

Olfaction deterioration in cognitive disorders in the elderly.

PubMed

Ottaviano, Giancarlo; Frasson, Giuliana; Nardello, Ennio; Martini, Alessandro

2016-02-01

Parkinson's and Alzheimer's diseases are widespread neurodegenerative pathologies. Parkinson's disease affects about 1 % of the population over the age of 65 years, while Alzheimer is considered the most common cause of dementia, with an annual incidence of 1 % in persons aged 65 years. It has been demonstrated that both these neurodegenerative diseases are associated with smell dysfunction. The aim of the present review is to describe briefly modern olfactory evaluation tools as well as the importance of olfactory sensitivity screening in the elderly, especially where cognitive disorders, such as Alzheimer's or Parkinson's diseases, are suspected. A brief literature review focusing on the basic principle of smell tests is illustrated together with their application in elderly patients affected by cognitive disorders, in particular Parkinson's and Alzheimer's diseases. Alzheimer's and Parkinson's diseases are both neurodegenerative disorders typically found in the elderly. As both diseases are characterized by the early presence of dysosmia, simple validated smell tests could very well help clinicians in the early diagnosis of these neuropathological conditions. Elderly patients complaining of smell loss and found to be dysosmic, by means of validated olfactory tests, should be neurologically evaluated as early as possible to detect slight motor abnormalities in an at-risk population.

Impact of erectile dysfunction and its subsequent treatment with sildenafil: qualitative study.

PubMed

Tomlinson, John; Wright, David

2004-05-01

To determine the effects of erectile dysfunction and to explore the impact of treatment with sildenafil (Viagra). An exploratory qualitative study with semistructured interviews. Men's health clinic in NHS hospital. 40 men who had had erectile dysfunction and had attended the clinic during the year before interview. Impact of erectile dysfunction on men, their expectations of sildenafil, and impact of treatment on men and their relationships. Issues explored with exploratory qualitative approach. Erectile dysfunction caused serious distress to all those men who experienced it, with marked effects on their self esteem and their relationships. Sildenafil, when it worked, caused a great improvement in wellbeing. The expectations raised by media hyperbole with the launch of sildenafil had an adverse effect on the morale of those who found it did not work. When, according to the patient, treatment did not work, the distress was severe and for many confirmed their lack of self worth. Further study is needed to explore the feelings of men affected by erectile dysfunction and their perception of treatment. Health professionals should be aware of the extreme distress erectile dysfunction can cause.

Behavioral and molecular changes in the mouse in response to prenatal exposure to the anti-epileptic drug valproic acid.

PubMed

Roullet, F I; Wollaston, L; Decatanzaro, D; Foster, J A

2010-10-13

Experiments in rodents have indicated that maternal valproic acid (VPA) exposure has permanent adverse effects upon neurological and behavioral development. In humans, prenatal exposure to VPA can induce fetal valproate syndrome, which has been associated with autism. The present study examined mouse pups exposed in utero to VPA, measuring physical development, olfactory discrimination, and social behavior as well as expression of plasticity-related genes, brain derived neurotrophic factor (BDNF) and NMDA receptor subunits NR2A and NR2B. VPA-exposed mice showed delayed physical development, impaired olfactory discrimination, and dysfunctional pre-weaning social behavior. In situ hybridization experiments revealed lower cortical expression of BDNF mRNA in VPA animals. These results support the validity of the VPA mouse model for human autism and suggest that alterations in plasticity-related genes may contribute to the behavioral phenotype. Copyright 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

Olfactory bulb dysgenesis, mirror neuron system dysfunction, and autonomic dysregulation as the neural basis for autism.

PubMed

Brang, David; Ramachandran, V S

2010-05-01

Autism is a disorder characterized by social withdrawal, impoverished language and empathy, and a profound inability to adopt another's viewpoint - a failure to construct a "theory of mind" for interpreting another person's thoughts and intentions. We previously showed that these symptoms might be explained, in part, by a paucity of mirror neurons. Prompted by an MRI report of an individual with autism, we now suggest that there may be, in addition, a congenital aplasia/dysplasia of the olfactory bulbs with consequent reduction of vasopressin and oxytocin receptor binding. There may also be sub-clinical temporal lobe epilepsy affecting the recently discovered third visual system that is rich in "empathy" related mirror neurons (MNS) and projects (via the TOP junction - just below the inferior parietal lobule) to limbic structures that regulate autonomic outflow. This causes deranged autonomic feedback, resulting in additional deficiencies in MNS with loss of emotional empathy and introspection.

Abnormal Olfaction in Parkinson's Disease Is Related to Faster Disease Progression.

PubMed

Cavaco, Sara; Gonçalves, Alexandra; Mendes, Alexandre; Vila-Chã, Nuno; Moreira, Inês; Fernandes, Joana; Damásio, Joana; Teixeira-Pinto, Armando; Bastos Lima, António

2015-01-01

A possible association between olfactory dysfunction and Parkinson's disease (PD) severity has been a topic of contention for the past 40 years. Conflicting reports may be partially explained by procedural differences in olfactory assessment and motor symptom evaluation. One hundred and sixty-six nondemented PD patients performed the Brief-Smell Identification Test and test scores below the estimated 20th percentile as a function of sex, age, and education (i.e., 80% specificity) were considered demographically abnormal. Patients underwent motor examination after 12 h without antiparkinsonian medication. Eighty-two percent of PD patients had abnormal olfaction. Abnormal performance on the Brief-Smell Identification Test was associated with higher disease severity (i.e., Hoehn and Yahr, Unified Parkinson's Disease Rating Scale-III, Freezing of Gait questionnaire, and levodopa equivalent dose), even when disease duration was taken into account. Abnormal olfaction in PD is associated with increased severity and faster disease progression.

Olfactory Function in Wave 2 of the National Social Life, Health, and Aging Project

PubMed Central

Wroblewski, Kristen E.; Schumm, L. Philip; Pinto, Jayant M.; Chen, Rachel C.; McClintock, Martha K.

2014-01-01

Objective. To investigate the sense of smell, including sensitivity and odor identification, and characterize the U.S. national prevalence of olfactory dysfunction in older adults, thereby facilitating further investigation of the substantial risks for older adults associated with this basic sensory ability. Method. The sense of smell was evaluated using the Olfactory Function Field Exam (OFFE), a measure designed specifically for field research, which assesses 3 components of olfaction: sensitivity to n-butanol (a standard testing odorant) and androstadienone (AND, a key social odor produced by humans), as well as the ability to identify odors. Respondents were randomly selected from the National Social Life, Health, and Aging Project Wave 2 sample to receive the OFFE (n = 2,304), and 2,212 consented to participate. Results. In the U.S. population aged 62–90, n-butanol detection ability was significantly worse at older ages (ordinal logistic regression, p < .001); however, there was no difference in detection ability between genders (p = .60). AND detection ability was also significantly worse at older ages (p = .003), but in contrast to n-butanol, women outperformed men (p = .001). As expected, odor identification ability was worse in older people than in younger (p < .001), and women were more accurate than men (p = .001). Discussion. We report for the first time 3 facets of olfactory function and its association with age and gender in a representative sample of U.S. older adults. Future analyses of these data are needed to elucidate the sense of smell’s role in physical, social, and mental health with aging. PMID:25360014

Different odor tests contribute differently to the evaluation of olfactory loss.

PubMed

Lötsch, Jörn; Reichmann, Heinz; Hummel, Thomas

2008-01-01

In a clinical context, the importance of the sense of smell has increasingly been recognized, for example, in terms of the evaluation of neurodegenerative disorders. In this study, 2 strategies of olfactory testing, a simple one and a more complex one, were compared with respect to their suitability to assess olfactory dysfunction. Odor threshold (T), discrimination (D), and identification (I) were assessed in a control sample of 916 males and 1160 females, aged 6-90 years, and in 81 men and 21 women, aged 38-80 years, suffering from idiopathic Parkinson's disease (IPD). Sums of the 3 subtest results T, D, and I yielded threshold discrimination identification (TDI) scores reflecting olfactory function. Sensitivity of any of the 3 subtests to confirm the diagnosis established by the composite TDI score was assessed separately for each test. Principal component analyses were applied to determine any common source of variance among the 3 specific subtests. Sensitivities of the subtests to provide the diagnosis established by the composite TDI score were 64% (T), 56% (D), and 47% (I), respectively. In IPD patients, each of the subtests provided the correct diagnosis (sensitivity >90%), as olfaction was impaired in 99% of the patient group. Two principal components emerged in both controls and IPD patients, with eigenvalues >0.5. The first component received high loadings from all factors. The second component received high loadings from odor threshold, whereas loadings from odor discrimination and identification were much smaller. In conclusion, combined testing of several components of olfaction, especially including assessment of thresholds, provides the most significant approach to the diagnosis of smell loss.

Olfaction and apathy in Alzheimer's disease, mild cognitive impairment, and healthy older adults.

PubMed

Seligman, Sarah C; Kamath, Vidyulata; Giovannetti, Tania; Arnold, Steven E; Moberg, Paul J

2013-01-01

Apathy is a prevalent neuropsychiatric manifestation in individuals with Alzheimer's disease (AD) that is associated with decreased social functioning and increased caregiver burden. Olfactory deficits are also commonly observed in AD, and prior work has indicated a link between increased apathy and olfactory dysfunction in individuals with Parkinson's disease. Here, we examined odor identification performance in patients with probable AD (n = 172), individuals with mild cognitive impairment (MCI; n = 112), and neurologically and psychiatrically healthy older adults (n = 132) and its relation to apathy, depression, and overall psychopathology. Participants were administered the Sniffin' Sticks odor identification test and measures assessing severity of apathy, depression, and overall neuropsychiatric symptomatology. Consistent with previous research, AD and MCI patients were significantly worse at identifying odors than healthy older adults. Additionally, a sex by diagnosis interaction was observed. AD patients had significantly higher levels of apathy relative to MCI and control participants. Of note, across the entire sample odor identification deficits were correlated with level of apathy at the level of p < 0.01, but not with depression or neuropsychiatric symptom severity, when controlling for Mini-Mental State Examination (MMSE) score. Collectively, these data suggest that olfactory disturbance and apathy in AD may result from the progression of disease pathology in shared neural substrates.

Hippocampal neurogenesis and cortical cellular plasticity in Wahlberg's epauletted fruit bat: a qualitative and quantitative study.

PubMed

Gatome, Catherine W; Mwangi, Deter K; Lipp, Hans-Peter; Amrein, Irmgard

2010-01-01

Species-specific characteristics of neuronal plasticity emerging from comparative studies can address the functional relevance of hippocampal or cortical plasticity in the light of ecological adaptation and evolutionary history of a given species. Here, we present a quantitative and qualitative analysis of neurogenesis in young and adult free-living Wahlberg's epauletted fruit bats. Using the markers for proliferating cell nuclear antigen (PCNA), bromodeoxyuridine (BrdU), doublecortin (DCX) and polysialic acid neural cell adhesion molecule (PSA-NCAM), our findings in the hippocampus, olfactory bulb and cortical regions are described and compared to reports in other mammals. Expressed as a percentage of the total number of granule cells, PCNA- and BrdU-positive cells accounted for 0.04 in young to 0.01% in adult animals; DCX-positive cells for 0.05 (young) to 0.01% (adult); PSA-NCAM-positive cells for 0.1 (young) to 0.02% (adult), and pyknotic cells for 0.007 (young) to 0.005% (adult). The numbers were comparable to other long-lived, late-maturing mammals such as primates. A significant increase in the total granule cell number from young to adult animals demonstrated the successful formation and integration of new cells. In adulthood, granule cell number appeared stable and was surprisingly low in comparison to other species. Observations in the olfactory bulb and rostral migratory stream were qualitatively similar to descriptions in other species. In the ventral horn of the lateral ventricle, we noted prominent expression of DCX and PSA-NCAM forming a temporal migratory stream targeting the piriform cortex, possibly reflecting the importance of olfaction to these species. Low, but persistent hippocampal neurogenesis in non-echolocating fruit bats contrasted the findings in echolocating microbats, in which hippocampal neurogenesis was largely absent. Together with the observed intense cortical plasticity in the olfactory system of fruit bats we suggest a differential influence of sensory modalities on hippocampal and cortical plasticity in this mammalian order. Copyright © 2010 S. Karger AG, Basel.

A comparative study of brain perfusion single-photon emission computed tomography and magnetic resonance imaging in patients with post-traumatic anosmia.

PubMed

Atighechi, Saeid; Salari, Hadi; Baradarantar, Mohammad Hossein; Jafari, Rozita; Karimi, Ghasem; Mirjali, Mehdi

2009-01-01

Loss of smell is a problem that can occur in up to 30% of patients with head trauma. The olfactory function investigation methods so far in use have mostly relied on subjective responses given by patients. Recently, some studies have used magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) to evaluate patients with post-traumatic anosmia. The present study seeks to detect post-traumatic anosmia and the areas in the brain that are related to olfactory impairment by using SPECT and MRI as imaging techniques. The study was conducted on 21 patients suffering from head injury and consequently anosmia as defined by an olfactory identification test. Two control groups (traumatic normosmic and nontraumatic healthy individuals) were selected. Brain MRI, qualitative and semiquantitative SPECT with 99mtc-ethyl-cysteinate-dimer were taken from all the patients. Then the brain SPECT and MRI were compared with each other. Semi-quantitative assessment of the brain perfusion SPECT revealed frontal, left parietal, and left temporal hypoperfusion as compared with the two control groups. Eighty-five percent of the anosmic patients had abnormal brain MRI. Regarding the MRI, the main abnormality proved to be in the anterior inferior region of the frontal lobes and olfactory bulbs. The findings of this study suggest that damage to the frontal lobes and olfactory bulbs as shown in the brain MRI and hypoperfusion in the frontal, left parietal, and left temporal lobes in the semiquantitative SPECT corresponds to post-traumatic anosmia. Further neurophysiological and imaging studies are definitely needed to set the idea completely.

Impact of endoscopic sinus surgery on olfaction and use of alternative components in odor threshold measurement.

PubMed

Gupta, Divya; Gulati, Achal; Singh, Ishwar; Tekur, Uma

2015-01-01

One of the major causes of olfactory disturbances is chronic rhinosinusitis (CRS), and the main surgical modality to treat CRS is functional endoscopic sinus surgery (FESS). It, therefore, is essential to assess the effect of this surgery on olfaction. Also, it is necessary to find new ways of measuring olfaction so as to reduce dependability on standard tests available. To study the prevalence of olfactory impairment in patients with CRS and to evaluate the impact of FESS on olfaction. The study also aims at investigating the use of other odorants in place of butanol-1 in the Connecticut Chemosensory Clinical Research Center test. Forty patients of CRS without nasal polyposis were included in the study to analyze the prevalence of olfactory dysfunction and examine the influence of FESS at 1 and 3 months after surgery. Computed tomography scores (Lund Mackay scores) were calculated preoperatively, whereas other tests, viz., visual analog scale scoring, nasal endoscopy (Lund Kennedy scoring), and composite olfactory testing with odor thresholds of butanol-1, peppermint, lemon, clove, and ethyl acetate were carried out before surgery and after surgery at 1 and 3 months. Of 40 patients, 70% had symptoms of hyposmia or of anosmia before surgery, which dropped to 22.5% at 1 month after surgery and to 10% at 3 months after surgery. Nasal endoscopy and visual analog scale scores improved significantly. Odor threshold and odor identification scores also improved compared with the preoperative levels. A significant positive correlation was found between the threshold scores of butanol-1 and other odorants, both before and after surgery. Significant improvement was observed in olfaction after FESS, both in patient responses and in objective testing. The olfactory results with peppermint, lemon, clove, and ethyl acetate were close to those with butanol-1, and, hence, these other odorants can be used in place of butanol-1 in measuring the odor threshold.

[Sense of smell, physiological ageing and neurodegenerative diseases: II. Ageing and neurodegenerative diseases].

PubMed

Fusari, A; Molina, J A

The sense of smell, which was once studied because of its biological and evolutionary significance, is today one of the centres of interest in research on normal and pathological ageing. The latest scientific developments point to an inversely proportional relationship between age and olfactory sensitivity. In certain neurodegenerative diseases this sensory decline is one of the first symptoms of the disorder and is correlated with the progression of the disease. In this work we are going to review the scientific knowledge on loss of sense of smell in ageing and in neurodegenerative diseases, with special attention given to Alzheimer's and Parkinson's diseases. A survey of studies that have examined the olfactory deficits in ageing and in some neurodegenerative diseases offers conclusive results about the presence of these impairments in the early stages of these disorders and even among healthy elderly persons. Although a number of causes contribute to these sensory losses in physiological ageing, a common neurological foundation has been proposed for Alzheimer's and Parkinson's diseases. Nevertheless, despite certain initial similarities, the olfactory deficits shown in these disorders seem to be qualitatively different.

Assessment of the psychosocial and mental health needs, dysfunction and coping mechanisms of violence affected populations in Bireuen Aceh. A qualitative study.

PubMed

Poudyal, Bhava; Bass, Judith; Subyantoro, Theodora; Jonathan, Abraham; Erni, Theresia; Bolton, Paul

2009-01-01

Qualitative research is important due to the shortage of literature in understanding cultural influences on psychosocial and mental health syndromes and their presentation, especially in developing countries. This qualitative study aims to investigate the psychosocial and mental health needs of populations in Aceh, Indonesia affected by over 30 years of conflict, their dysfunction, and their positive coping mechanisms. Results from this qualitative assessment indicate the presence of depression, anxiety and somatic symptoms. The data provide local terminology and ways in which the local population describes their own distress, which is an important addition to the understanding of the mental health consequences of this conflict. The data has been used to develop appropriate intervention strategies and adapt and validate assessment tools to measure psychological distress, dysfunction and coping mechanisms.

Odors identification differences in deficit and nondeficit schizophrenia.

PubMed

Pełka-Wysiecka, Justyna; Wroński, Michał; Bieńkowski, Przemysław; Murawiec, Sławomir; Samochowiec, Agnieszka; Samochowiec, Jerzy

2016-04-01

There is evidence that deficit schizophrenia (DS) is associated with neuroanatomical changes in structures including those involved in olfaction. Olfactory dysfunction, which includes impaired odor identification, is found in patients with schizophrenia and their family members. 82 patients with DS and 72 patients with NDS (nondeficit schizophrenia), somatically healthy and without acute psychotic symptoms undertook a smell identification test using the 16-item Sniffin' Sticks ID test. Demographic and psychometric data were collected. No differences in the course of the illness, perinatal history and demographic data were found between the DS and NDS groups. No differences in the number of correctly identified odor samples were found. Some differences in the qualitative identification of samples between DS and NDS were found in the groups of female (fewer correct identifications of cinnamon and pineapple smells in DS) and male patients (fewer correct identifications of the smell of rose and more correct identifications of the smell of orange than in NDS). No overall differences between DS and NDS regarding odors identification have been found. The results seem to indicate some specific deficits in the identification of markers of rose, pineapple, orange and cinnamon. Copyright © 2015 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Paraneoplastic limbic encephalitis associated with mixed olfactory neuroblastoma and craniopharyngioma: A case report and literature review.

PubMed

Nagafuji, Hiroshi; Yokoi, Hidenori; Fujiwara, Masachika; Sato, Dai; Saito, Koichiro

2018-06-01

Paraneoplastic limbic encephalitis (PLE) is a rare disorder of the nervous system associated with malignant disease. It has a subacute onset with the following symptoms: cognitive dysfunction, seizures, irritability, hallucinations, and short-term memory loss. Herein, we report the case of a 35-year-old man with PLE, an olfactory neuroblastoma (ONB) admixed with craniopharyngioma, and serum anti-Hu antibodies. The patient presented with generalized seizures, short-term memory loss, and a polypoid mass located high in the nasal cavity. He underwent surgical resection of the tumor and postoperative chemoradiotherapy with concurrent intra-arterial cisplatin administration. Pathological examination indicated an ONB admixed with craniopharyngioma. The patient's neurological symptoms gradually diminished after surgery. No evidence of recurrence was observed during a 4-year follow-up. We reported a histologically unusual heterogeneous tumor that comprised ONB and craniopharyngioma. This is the first reported case of PLE with anti-Hu antibodies possibly associated with ONB admixed with craniopharyngioma.

Traumatic Brain Injury and Olfaction: A Systematic Review

PubMed Central

Schofield, Peter William; Moore, Tammie Maree; Gardner, Andrew

2014-01-01

Traumatic brain injury (TBI) is a common condition that is often complicated by neuropsychiatric sequelae that can have major impacts on function and quality of life. An alteration in the sense of smell is recognized as a relatively common complication of TBI; however in clinical practice, this complication may not be sought or adequately characterized. We conducted a systematic review of studies concerned with olfactory functioning following TBI. Our predetermined criteria led to the identification of 25 studies published in English, which we examined in detail. We have tabulated the data from these studies in eight separate tables, beginning with Table 1, which highlights each study’s key findings, and we provide a summary/synthesis of the findings in the accompanying results and discussion sections. Despite widely differing methodologies, the studies attest to a high frequency of post-TBI olfactory dysfunction and indicate that its presence can serve as a potential marker of additional structural or functional morbidities. PMID:24478752

Olfactory discrimination varies in mice with different levels of α7-nicotinic acetylcholine receptor expression.

PubMed

Hellier, Jennifer L; Arevalo, Nicole L; Blatner, Megan J; Dang, An K; Clevenger, Amy C; Adams, Catherine E; Restrepo, Diego

2010-10-28

Previous studies have shown that schizophrenics have decreased expression of α7-nicotinic acetylcholine (α7) receptors in the hippocampus and other brain regions, paranoid delusions, disorganized speech, deficits in auditory gating (i.e., inability to inhibit neuronal responses to repetitive auditory stimuli), and difficulties in odor discrimination and detection. Here we use mice with decreased α7 expression that also show a deficit in auditory gating to determine if these mice have similar deficits in olfaction. In the adult mouse olfactory bulb (OB), α7 expression localizes in the glomerular layer; however, the functional role of α7 is unknown. We show that inbred mouse strains (i.e., C3H and C57) with varying α7 expressions (e.g., α7 wild-type [α7+/+], α7 heterozygous knock-out [α7+/-] and α7 homozygous knock-out mice [α7-/-]) significantly differ in odor discrimination and detection of chemically-related odorant pairs. Using [(125)I] α-bungarotoxin (α-BGT) autoradiography, α7 expression was measured in the OB. As previously demonstrated, α-BGT binding was localized to the glomerular layer. Significantly more expression of α7 was observed in C57 α7+/+ mice compared to C3H α7+/+ mice. Furthermore, C57 α7+/+ mice were able to detect a significantly lower concentration of an odor in a mixture compared to C3H α7+/+ mice. Both C57 and C3H α7+/+ mice discriminated between chemically-related odorants sooner than α7+/- or α7-/- mice. These data suggest that α7-nicotinic-receptors contribute strongly to olfactory discrimination and detection in mice and may be one of the mechanisms producing olfactory dysfunction in schizophrenics. Copyright © 2010 Elsevier B.V. All rights reserved.

The effects of chronic alcoholism on cell proliferation in the human brain.

PubMed

Sutherland, G T; Sheahan, P J; Matthews, J; Dennis, C V P; Sheedy, D S; McCrossin, T; Curtis, M A; Kril, J J

2013-09-01

Neurogenesis continues in the human subventricular zone and to a lesser extent in the hippocampal subgranular zone throughout life. Subventricular zone-derived neuroblasts migrate to the olfactory bulb where survivors become integrated as interneurons and are postulated to contribute to odor discrimination. Adult neurogenesis is dysregulated in many neurological, neurovascular and neurodegenerative diseases. Alcohol abuse can result in a neurodegenerative condition called alcohol-related brain damage. Alcohol-related brain damage manifests clinically as cognitive dysfunction and the loss of smell sensation (hyposmia) and pathologically as generalized white matter atrophy and focal neuronal loss. The exact mechanism linking chronic alcohol intoxication with alcohol-related brain damage remains largely unknown but rodent models suggest that decreased neurogenesis is an important component. We investigated this idea by comparing proliferative events in the subventricular zone and olfactory bulb of a well-characterized cohort of 15 chronic alcoholics and 16 age-matched controls. In contrast to the findings in animal models there was no difference in the number of proliferative cell nuclear antigen-positive cells in the subventricular zone of alcoholics (mean±SD=28.7±20.0) and controls (27.6±18.9, p=1.0). There were also no differences in either the total (p=0.89) or proliferative cells (p=0.98) in the granular cell layer of the olfactory bulb. Our findings show that chronic alcohol consumption does not affect cell proliferation in the human SVZ or olfactory bulb. In fact only microglial proliferation could be demonstrated in the latter. Therefore neurogenic deficits are unlikely to contribute to hyposmia in chronic alcoholics. Copyright © 2013 Elsevier Inc. All rights reserved.

Impaired Sense of Smell in a Drosophila Parkinson’s Model

PubMed Central

Poddighe, Simone; Bhat, Krishna Moorthi; Setzu, Maria Dolores; Solla, Paolo; Angioy, Anna Maria; Marotta, Roberto; Ruffilli, Roberta; Marrosu, Francesco; Liscia, Anna

2013-01-01

Parkinson’s disease (PD) is one of the most common neurodegenerative disease characterized by the clinical triad: tremor, akinesia and rigidity. Several studies have suggested that PD patients show disturbances in olfaction at the earliest onset of the disease. The fruit fly Drosophila melanogaster is becoming a powerful model organism to study neurodegenerative diseases. We sought to use this system to explore olfactory dysfunction, if any, in PINK1 mutants, which is a model for PD. PINK1 mutants display many important diagnostic symptoms of the disease such as akinetic motor behavior. In the present study, we describe for the first time, to the best of our knowledge, neurophysiological and neuroanatomical results concerning the olfactory function in PINK1 mutant flies. Electroantennograms were recorded in response to synthetic and natural volatiles (essential oils) from groups of PINK1 mutant adults at three different time points in their life cycle: one from 3–5 day-old flies, from 15–20 and from 27–30 days. The results obtained were compared with the same age-groups of wild type flies. We found that mutant adults showed a decrease in the olfactory response to 1-hexanol, α-pinene and essential oil volatiles. This olfactory response in mutant adults decreased even more as the flies aged. Immunohistological analysis of the antennal lobes in these mutants revealed structural abnormalities, especially in the expression of Bruchpilot protein, a marker for synaptic active zones. The combination of electrophysiological and morphological results suggests that the altered synaptic organization may be due to a neurodegenerative process. Our results indicate that this model can be used as a tool for understanding PD pathogensis and pathophysiology. These results help to explore the potential of using olfaction as a means of monitoring PD progression and developing new treatments. PMID:24009736

A controlled trial of aromatherapy for agitation in nursing home patients with dementia.

PubMed

Snow, Lynn A; Hovanec, Linda; Brandt, Jason

2004-06-01

Two controlled trials of aromatherapy to decrease agitation in persons with dementia have recently produced promising results. However, both studies combined the use of essential oils with massage. Thus, it is unclear if the effect of the aromatherapy intervention was the result of smelling or the cutaneous absorption of the oils. The purpose of this study was to determine whether smelling lavender oil decreases the frequency of agitated behaviors in patients with dementia. The study design was within-subjects ABCBA (A = lavender oil, B = thyme oil, C = unscented grapeseed oil): 4 weeks of baseline measurement, 2 weeks for each of the five treatment conditions (10-week total intervention time), and 2 weeks of postintervention measurement. Oil was placed every 3 hours on an absorbent fabric sachet pinned near the collarbone of each participant's shirt. A long-term care facility specifically for persons with dementia. Seven agitated nursing home residents with advanced dementia. Agitation was assessed every 2 days using a modified Cohen-Mansfield Agitation Inventory. Olfactory functioning was assessed with structured olfactory identification and discrimination tasks, and with qualitative behavioral observation during those tasks. Split-middle analyses conducted separately for each patient revealed no treatment effects specific to lavender, no treatment effects nonspecific to pleasant smelling substances, and no treatment effects dependent on order of treatment administration. There were no differences between participants with more and less intact olfactory abilities. There is significant evidence in the neurologic and neuropsychologic literature that persons with dementia have impaired olfactory abilities. Concordant with this literature, this study found no support for the use of a purely olfactory form of aromatherapy to decrease agitation in severely demented patients. Cutaneous application of the essential oil may be necessary to achieve the effects reported in previous controlled studies. Copyright Mary Ann Liebert, Inc.

Malodorous consequences: what comprises negligence in anosmia litigation?

PubMed

Svider, Peter F; Mauro, Andrew C; Eloy, Jean Anderson; Setzen, Michael; Carron, Michael A; Folbe, Adam J

2014-03-01

Our objectives were to evaluate factors raised in malpractice litigation in which plaintiffs alleged that physician negligence led to olfactory dysfunction. We analyzed publically available federal and court records using Westlaw, a widely used computerized legal database. Pertinent jury verdicts and settlements were comprehensively examined for alleged causes of malpractice (including procedures for iatrogenic causes), defendant specialty, patient demographics, and other factors raised in legal proceedings. Of 25 malpractice proceedings meeting inclusion criteria, 60.0% were resolved for the defendant, 12.0% were settled, and 28.0% had jury-awarded damages. Median payments were significant ($300,000 and $412,500 for settlements and awards, respectively). Otolaryngologists were the most frequently named defendants (68.0%), with the majority of iatrogenic cases (55.0%) related to rhinologic procedures. Associated medical events accompanying anosmia included dysgeusia, cerebrospinal fluid leaks, and meningitis. Other alleged factors included requiring additional surgery (80.0%), unnecessary procedures (47.4% of iatrogenic procedural cases), untimely diagnosis leading to anosmia (44.0%), inadequate informed consent (35.0%), dysgeusia (56.0%), and psychological sequelae (24.0%). Olfactory dysfunction can adversely affect quality of life and thus is a potential area for malpractice litigation. This is particularly true for iatrogenic causes of anosmia, especially following rhinologic procedures. Settlements and damages awarded were considerable, making an understanding of factors detailed in this analysis of paramount importance for the practicing otolaryngologist. This analysis reinforces the importance of explicitly including anosmia in a comprehensive informed consent process for any rhinologic procedure. © 2013 ARS-AAOA, LLC.

Association Between Olfactory Dysfunction and Amnestic Mild Cognitive Impairment and Alzheimer Disease Dementia

PubMed Central

Roberts, Rosebud O.; Christianson, Teresa J. H.; Kremers, Walter K.; Mielke, Michelle M.; Machulda, Mary M.; Vassilaki, Maria; Alhurani, Rabe E.; Geda, Yonas E.; Knopman, David S.; Petersen, Ronald C.

2015-01-01

IMPORTANCE To increase the opportunity to delay or prevent mild cognitive impairment (MCI) or dementia due to Alzheimer's disease (AD), markers of early detection are essential. Olfactory impairment may be an important clinical marker and predictor of these conditions and may help identify persons at increased risk. OBJECTIVE To examine associations of impaired olfaction with incident MCI subtypes, and progression from MCI subtypes to AD dementia. DESIGN, SETTING, AND PARTICIPANTS Participants enrolled in the population-based, prospective Mayo Clinic Study of Aging were clinically evaluated at baseline and every 15-months thereafter, and classified as having normal cognition, MCI (amnestic, aMCI and nonamnestic, naMCI), and dementia. We administered the Brief Smell Identification Test (B-SIT) to assess olfactory function. MAIN OUTCOMES AND MEASURES Mild cognitive impairment, AD dementia, longitudinal change in cognitive performance measures. RESULTS Over a mean 3.5 years of follow-up, there were 250 incident cases of MCI among 1430 cognitively normal participants. We observed an association between decreasing olfactory identification, as measured by decrease in number of correct responses in B-SIT score, and an increased risk of aMCI. Compared to the upper B-SIT quartile (Q4, best scores), hazard ratios (HR) were 1.12; P = 0.68 for Q3; HR, 1.95; P =0.003 for Q2; and HR, 2.18; P = 0.001 (worst scores; p for trend <0.001) after adjustment for sex and education, with age as the time scale. There was no association with naMCI. There were 64 incident dementia cases among 221 prevalent MCI cases. The B-SIT score also predicted progression from aMCI to AD, with a significant dose-response with worsening B-SIT quartiles. Compared to Q4, HR estimates were 3.02, P = 0.038 for Q3; HR, 3.63; P = 0.024 for Q2; and HR, 5.20; P = 0.001 for Q1. After adjusting for key predictors of MCI risk, B-SIT (as a continuous measure) remained a significant predictor of MCI (HR, 1.10; p < 0.001), and improved the model concordance. CONCLUSIONS AND RELEVANCE Olfactory impairment predicts incident aMCI and progression from aMCI to AD. These findings are consistent with previous studies that have reported associations of olfactory impairment with cognitive impairment in late life, and suggest that olfactory tests have potential utility for screening for MCI and MCI that is likely to progress. PMID:26569387

Olfactory Hallucinations without Clinical Motor Activity: A Comparison of Unirhinal with Birhinal Phantosmia

PubMed Central

Henkin, Robert I.; Potolicchio, Samuel J.; Levy, Lucien M.

2013-01-01

Olfactory hallucinations without subsequent myoclonic activity have not been well characterized or understood. Herein we describe, in a retrospective study, two major forms of olfactory hallucinations labeled phantosmias: one, unirhinal, the other, birhinal. To describe these disorders we performed several procedures to elucidate similarities and differences between these processes. From 1272, patients evaluated for taste and smell dysfunction at The Taste and Smell Clinic, Washington, DC with clinical history, neurological and otolaryngological examinations, evaluations of taste and smell function, EEG and neuroradiological studies 40 exhibited cyclic unirhinal phantosmia (CUP) usually without hyposmia whereas 88 exhibited non-cyclic birhinal phantosmia with associated symptomology (BPAS) with hyposmia. Patients with CUP developed phantosmia spontaneously or after laughing, coughing or shouting initially with spontaneous inhibition and subsequently with Valsalva maneuvers, sleep or nasal water inhalation; they had frequent EEG changes usually ipsilateral sharp waves. Patients with BPAS developed phantosmia secondary to several clinical events usually after hyposmia onset with few EEG changes; their phantosmia could not be initiated or inhibited by any physiological maneuver. CUP is uncommonly encountered and represents a newly defined clinical syndrome. BPAS is commonly encountered, has been observed previously but has not been clearly defined. Mechanisms responsible for phantosmia in each group were related to decreased gamma-aminobutyric acid (GABA) activity in specific brain regions. Treatment which activated brain GABA inhibited phantosmia in both groups. PMID:24961619

Interobserver and Intraobserver Agreement on Qualitative Assessments of Right Ventricular Dysfunction With Echocardiography in Patients With Pulmonary Embolism.

PubMed

Weekes, Anthony J; Oh, Laura; Thacker, Gregory; Johnson, Angela K; Runyon, Michael; Rose, Geoffrey; Johnson, Thomas; Templin, Megan; Norton, H James

2016-10-01

To evaluate observer agreement using qualitative goal-directed echocardiographic criteria for right ventricular (RV) dysfunction prognostication in submassive pulmonary embolism (PE). Two emergency physicians and 2 cardiologists independently reviewed 31 packets of goal-directed echocardiographic video clips consisting of at least 3 windows obtained by emergency physicians from normotensive patients with PE. Nine packets were repeated to assess for intraobserver agreement. Right ventricular dysfunction criteria on goal-directed echocardiography were as follows: RV enlargement was present, with a right-to-left ventricular basal diameter ratio of 1.0 or higher and blunting of the apex of the RV in 2 or more different windows; RV systolic dysfunction was present if the tricuspid annulus moved toward the apex 10 mm or less and there was RV free wall hypokinesis; and septal deviation was present with any flattening or deviation of the ventricular septum toward the left ventricle. Among the 4 participants, there was 83.9% agreement on the presence or absence of RV enlargement (κ = 0.84), 74.2% agreement on the presence or absence of RV systolic dysfunction (κ = 0.69), and 71.0% agreement on the presence or absence of septal deviation (κ = 0.59). Intraobserver agreement was 100% for each RV dysfunction variable for each observer (κ = 1.0). Agreement was substantial for both severe RV enlargement and RV systolic dysfunction and moderate for septal deviation. Right ventricular dysfunction assessment with qualitative goal-directed echocardiographic criteria is reproducible for PE risk stratification.

Furthering the understanding of olfaction, prevalence of loss of smell and risk factors: a population-based survey (OLFACAT study)

PubMed Central

Mullol, Joaquim; Alobid, Isam; Mariño-Sánchez, Franklin; Quintó, Llorenç; de Haro, Josep; Bernal-Sprekelsen, Manuel; Valero, Antonio; Picado, Cèsar; Marin, Concepció

2012-01-01

Objectives To investigate olfaction in general population, prevalence of olfactory dysfunction and related risk factors. Design Cross-sectional population-based survey, distributing four microencapsulated odorants (rose, banana, musk and gas) and two self-administered questionnaires (odour description; epidemiology/health status). Setting The survey was distributed to general population through a bilingual (Catalan, Spanish) newspaper in Catalonia (Spain), on December 2003. Participants Newspaper readers of all ages and gender; 9348 surveys were analysed from the 10 783 returned. Main outcome measures Characteristics of surveyed population, olfaction by age and gender, smell self-perception and smell impairment risk factors. Terms normosmia, hyposmia and anosmia were used when participants detected, recognised or identified all four, one to three or none of the odours, respectively. Results Survey profile was a 43-year-old woman with medium–high educational level, living in a city. Olfaction was considered normal in 80.6% (detection), 56% (recognition/memory) and 50.7% (identification). Prevalence of smell dysfunction was 19.4% for detection (0.3% anosmia, 19.1% hyposmia), 43.5% for recognition (0.2% anosmia, 43.3% hyposmia) and 48.8% for identification (0.8% anosmia, 48% hyposmia). Olfaction was worse (p<0.0001) in men than in women through all ages. There was a significant age-related smell detection decline however smell recognition and identification increased up to fourth decade and declined after the sixth decade of life. Risk factors for anosmia were: male gender, loss of smell history and poor olfactory self-perception for detection; low educational level, poor self-perception and pregnancy for recognition; and older age, poor self-perception and history of head trauma and loss of smell for identification. Smoking and exposure to noxious substances were mild protective factors for smell recognition. Conclusions Sense of smell in women is better than in men suggesting a learning process during life with deterioration in older ages. Poor self-perception, history of smell loss, head trauma and pregnancy are potential risk factors for olfactory disorders. PMID:23135536

The Bradford Hill criteria and zinc-induced anosmia: a causality analysis.

PubMed

Davidson, Terence M; Smith, Wendy M

2010-07-01

To apply the Bradford Hill criteria, which are widely used to establish causality between an environmental agent and disease, to evaluate the relationship between over-the-counter intranasal zinc gluconate therapy and anosmia. Patient and literature review applying the Bradford Hill criteria on causation. University of California, San Diego, Nasal Dysfunction Clinic. The study included 25 patients who presented to the University of California, San Diego, Nasal Dysfunction Clinic complaining of acute-onset anosmia after intranasal application of homeopathic zinc gluconate gel. Each of the 9 Bradford Hill criteria--strength of association, consistency, specificity, temporality, biological gradient (dose-response), biological plausibility, biological coherence, experimental evidence, and analogy--was applied to intranasal zinc gluconate therapy and olfactory dysfunction using published, peer-reviewed medical literature and reported clinical experiences. Clinical, biological, and experimental data support the Bradford Hill criteria to demonstrate that intranasal zinc gluconate therapy causes hyposmia and anosmia. The Bradford Hill criteria represent an important tool for scientifically determining cause between environmental exposure and disease. Increased Food and Drug Administration oversight of homeopathic medications is needed to monitor the safety of these popular remedies.

At the interface of sensory and motor dysfunctions and Alzheimer’s Disease

PubMed Central

Albers, Mark W.; Gilmore, Grover C.; Kaye, Jeffrey; Murphy, Claire; Wingfield, Arthur; Bennett, David A.; Boxer, Adam L.; Buchman, Aron S.; Cruickshanks, Karen J.; Devanand, Davangere P.; Duffy, Charles J.; Gall, Christine M.; Gates, George A.; Granholm, Ann-Charlotte; Hensch, Takao; Holtzer, Roee; Hyman, Bradley T.; Lin, Frank R.; McKee, Ann C.; Morris, John C.; Petersen, Ronald C.; Silbert, Lisa C.; Struble, Robert G.; Trojanowski, John Q.; Verghese, Joe; Wilson, Donald A.; Xu, Shunbin; Zhang, Li I.

2014-01-01

Recent evidence indicates that sensory and motor changes may precede the cognitive symptoms of Alzheimer’s disease (AD) by several years and may signify increased risk of developing AD. Traditionally, sensory and motor dysfunctions in aging and AD have been studied separately. To ascertain the evidence supporting the relationship between age-related changes in sensory and motor systems and the development of AD and to facilitate communication between several disciplines, the National Institute on Aging held an exploratory workshop titled “Sensory and Motor Dysfunctions in Aging and Alzheimer’s Disease”. The scientific sessions of the workshop focused on age-related and neuropathological changes in the olfactory, visual, auditory, and motor systems, followed by extensive discussion and hypothesis generation related to the possible links among sensory, cognitive, and motor domains in aging and AD. Based on the data presented and discussed at this workshop, it is clear that sensory and motor regions of the CNS are affected by Alzheimer pathology and that interventions targeting amelioration of sensory-motor deficits in AD may enhance patient function as AD progresses. PMID:25022540

Error behaviors associated with loss of competency in Alzheimer's disease.

PubMed

Marson, D C; Annis, S M; McInturff, B; Bartolucci, A; Harrell, L E

1999-12-10

To investigate qualitative behavioral changes associated with declining medical decision-making capacity (competency) in patients with AD. Qualitative measures can yield clinical information about functional changes in neurologic disease not available through quantitative measures. Normal older controls (n = 21) and patients with mild and moderate probable AD (n = 72) were compared using a standardized competency measure and neuropsychological measures. A system of 16 qualitative error scores representing conceptual domains of language, executive dysfunction, affective dysfunction, and compensatory responses was used to analyze errors produced on the competency measure. Patterns of errors were examined across groups. Relationships between error behaviors and competency performance were determined, and neurocognitive correlates of specific error behaviors were identified. AD patients demonstrated more miscomprehension, factual confusion, intrusions, incoherent responses, nonresponsive answers, loss of task, and delegation than controls. Errors in the executive domain (loss of task, nonresponsive answer, and loss of detachment) were key predictors of declining competency performance by AD patients. Neuropsychological analyses in the AD group generally confirmed the conceptual domain assignments of the qualitative scores. Loss of task, nonresponsive answers, and loss of detachment were key behavioral changes associated with declining competency of AD patients and with neurocognitive measures of executive dysfunction. These findings support the growing linkage between executive dysfunction and competency loss.

Steroid-Responsive Chronic Schizophreniform Syndrome in the Context of Mildly Increased Antithyroid Peroxidase Antibodies.

PubMed

Endres, Dominique; Perlov, Evgeniy; Riering, Anne Nicole; Maier, Viktoria; Stich, Oliver; Dersch, Rick; Venhoff, Nils; Erny, Daniel; Mader, Irina; Tebartz van Elst, Ludger

2017-01-01

Schizophreniform syndromes can be divided into primary forms from polygenic causes or secondary forms due to immunological, epileptiform, monogenic, or degenerative causes. Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT) is a secondary immunological form associated with increased thyroid antibodies, such as antithyroid peroxidase antibodies and shows a good response to corticosteroids. We present the case of a 41-year-old woman suffering from a schizophreniform syndrome. Starting at the age of 35, she developed psychotic exacerbations with formal thought disorder, acoustic hallucinations, cenesthopathic experiences, and loss of ego boundaries. At the same time, she began to suffer from chronic sexual delusions and olfactory hallucinations, which did not respond to neuroleptic medication. Her levels of antithyroid peroxidase antibodies were slightly increased, and the blood-brain barrier was disturbed. An electroencephalogram (EEG) showed intermittent generalized slowing, and cerebral magnetic resonance imaging (cMRI) depicted mild temporolateral atrophy. High-dose corticosteroid treatment led to convincing improvement of attentional performance and the disappearance of delusions and olfactory hallucinations. SREAT can mimic typical symptoms of schizophreniform syndromes. The increased titer of antithyroid peroxidase antibodies in combination with the EEG slowing, blood-brain barrier dysfunction, and the cMRI alterations were the basis for suspecting an immunological cause in our patient. Chronic delusions, olfactory hallucinations, and cognitive deficits were successfully treated with corticosteroids. The occurrence of secondary immunological forms of schizophreniform syndromes demonstrates the need for innovative immunosuppressive treatment options.

The adaptive significance of adult neurogenesis: an integrative approach

PubMed Central

Konefal, Sarah; Elliot, Mick; Crespi, Bernard

2013-01-01

Adult neurogenesis in mammals is predominantly restricted to two brain regions, the dentate gyrus (DG) of the hippocampus and the olfactory bulb (OB), suggesting that these two brain regions uniquely share functions that mediate its adaptive significance. Benefits of adult neurogenesis across these two regions appear to converge on increased neuronal and structural plasticity that subserves coding of novel, complex, and fine-grained information, usually with contextual components that include spatial positioning. By contrast, costs of adult neurogenesis appear to center on potential for dysregulation resulting in higher risk of brain cancer or psychological dysfunctions, but such costs have yet to be quantified directly. The three main hypotheses for the proximate functions and adaptive significance of adult neurogenesis, pattern separation, memory consolidation, and olfactory spatial, are not mutually exclusive and can be reconciled into a simple general model amenable to targeted experimental and comparative tests. Comparative analysis of brain region sizes across two major social-ecological groups of primates, gregarious (mainly diurnal haplorhines, visually-oriented, and in large social groups) and solitary (mainly noctural, territorial, and highly reliant on olfaction, as in most rodents) suggest that solitary species, but not gregarious species, show positive associations of population densities and home range sizes with sizes of both the hippocampus and OB, implicating their functions in social-territorial systems mediated by olfactory cues. Integrated analyses of the adaptive significance of adult neurogenesis will benefit from experimental studies motivated and structured by ecologically and socially relevant selective contexts. PMID:23882188

Does the cycad genotoxin MAM implicated in Guam ALS-PDC induce disease-relevant changes in mouse brain that includes olfaction?

PubMed

Kisby, Glen; Palmer, Valerie; Lasarev, Mike; Fry, Rebecca; Iordanov, Mihail; Magun, Eli; Samson, Leona; Spencer, Peter

2011-11-01

Western Pacific amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC), a prototypical neurodegenerative disease (tauopathy) affecting distinct genetic groups with common exposure to neurotoxic chemicals in cycad seed, has many features of Parkinson's and Alzheimer's diseases (AD), including early olfactory dysfunction. Guam ALS-PDC incidence correlates with cycad flour content of cycasin and its aglycone methylazoxymethanol (MAM), which produces persistent DNA damage (O(6)-methylguanine) in the brains of mice lacking O(6)-methylguanine methyltransferase (Mgmt(-/-)). We described in Mgmt(-/-)mice up to 7 days post-MAM treatment that brain DNA damage was linked to brain gene expression changes found in human neurological disease, cancer, and skin and hair development. This addendum reports 6 months post-MAM treatment- related brain transcriptional changes as well as elevated mitogen activated protein kinases and increased caspase-3 activity, both of which are involved in tau aggregation and neurofibrillary tangle formation typical of ALS-PDC and AD, plus transcriptional changes in olfactory receptors. Does cycasin act as a "slow (geno)toxin" in ALS-PDC?

Caspase inhibition in select olfactory neurons restores innate attraction behavior in aged Drosophila.

PubMed

Chihara, Takahiro; Kitabayashi, Aki; Morimoto, Michie; Takeuchi, Ken-ichi; Masuyama, Kaoru; Tonoki, Ayako; Davis, Ronald L; Wang, Jing W; Miura, Masayuki

2014-06-01

Sensory and cognitive performance decline with age. Neural dysfunction caused by nerve death in senile dementia and neurodegenerative disease has been intensively studied; however, functional changes in neural circuits during the normal aging process are not well understood. Caspases are key regulators of cell death, a hallmark of age-related neurodegeneration. Using a genetic probe for caspase-3-like activity (DEVDase activity), we have mapped age-dependent neuronal changes in the adult brain throughout the lifespan of Drosophila. Spatio-temporally restricted caspase activation was observed in the antennal lobe and ellipsoid body, brain structures required for olfaction and visual place memory, respectively. We also found that caspase was activated in an age-dependent manner in specific subsets of Drosophila olfactory receptor neurons (ORNs), Or42b and Or92a neurons. These neurons are essential for mediating innate attraction to food-related odors. Furthermore, age-induced impairments of neural transmission and attraction behavior could be reversed by specific inhibition of caspase in these ORNs, indicating that caspase activation in Or42b and Or92a neurons is responsible for altering animal behavior during normal aging.

Olfaction evaluation and correlation with brain atrophy in Bardet-Biedl syndrome.

PubMed

Braun, J-J; Noblet, V; Durand, M; Scheidecker, S; Zinetti-Bertschy, A; Foucher, J; Marion, V; Muller, J; Riehm, S; Dollfus, H; Kremer, S

2014-12-01

Bardet-Biedl syndrome (BBS) is a well-recognized ciliopathy characterized by cardinal features namely: early onset retinitis pigmentosa, polydactyly, obesity, hypogonadism, renal and cognitive impairment. Recently, disorders of olfaction (anosmia, hyposmia) have been also described in BBS patients. Moreover, morphological brain anomalies have been reported and prompt for further investigations to determine whether they are primary or secondary to peripheral organ involvement (i.e. visual or olfactory neuronal tissue). The objective of this article is to evaluate olfactory disorders in BBS patients and to investigate putative correlation with morphological cerebral anomalies. To this end, 20 BBS patients were recruited and evaluated for olfaction using the University of Pennsylvania Smell Identification Test (UPSIT). All of them underwent a structural magnetic resonance imaging (MRI) scan. We first investigated brain morphological differences between BBS subjects and 14 healthy volunteers. Then, we showed objective olfaction disorders in BBS patients and highlight correlation between gray matter volume reduction and olfaction dysfunction in several brain areas. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

An Investigation on the Role of Spike Latency in an Artificial Olfactory System

PubMed Central

Martinelli, Eugenio; Polese, Davide; Dini, Francesca; Paolesse, Roberto; Filippini, Daniel; Lundström, Ingemar; Di Natale, Corrado

2011-01-01

Experimental studies have shown that the reactions to external stimuli may appear only few hundreds of milliseconds after the physical interaction of the stimulus with the proper receptor. This behavior suggests that neurons transmit the largest meaningful part of their signal in the first spikes, and than that the spike latency is a good descriptor of the information content in biological neural networks. In this paper this property has been investigated in an artificial sensorial system where a single layer of spiking neurons is trained with the data generated by an artificial olfactory platform based on a large array of chemical sensors. The capability to discriminate between distinct chemicals and mixtures of them was studied with spiking neural networks endowed with and without lateral inhibitions and considering as output feature of the network both the spikes latency and the average firing rate. Results show that the average firing rate of the output spikes sequences shows the best separation among the experienced vapors, however the latency code is able in a shorter time to correctly discriminate all the tested volatile compounds. This behavior is qualitatively similar to those recently found in natural olfaction, and noteworthy it provides practical suggestions to tail the measurement conditions of artificial olfactory systems defining for each specific case a proper measurement time. PMID:22194721

"Till Death Do Us Part": A Potential Irreversible Link Between Aberrant Cell Cycle Control and Neurodegeneration in the Adult Olfactory Bulb.

PubMed

Omais, Saad; Jaafar, Carine; Ghanem, Noël

2018-01-01

Adult neurogenesis (AN) is an ongoing developmental process that generates newborn neurons in the olfactory bulb (OB) and the hippocampus (Hi) throughout life and significantly contributes to brain plasticity. Adult neural stem and progenitor cells (aNSPCs) are relatively limited in number and fate and are spatially restricted to the subventricular zone (SVZ) and the subgranular zone (SGZ). During AN, the distinct roles played by cell cycle proteins extend beyond cell cycle control and constitute key regulatory mechanisms involved in neuronal maturation and survival. Importantly, aberrant cell cycle re-entry (CCE) in post-mitotic neurons has been strongly linked to the abnormal pathophysiology in rodent models of neurodegenerative diseases with potential implications on the etiology and progression of such diseases in humans. Here, we present an overview of AN in the SVZ-OB and olfactory epithelium (OE) in mice and humans followed by a comprehensive update of the distinct roles played by cell cycle proteins including major tumors suppressor genes in various steps during neurogenesis. We also discuss accumulating evidence underlining a strong link between abnormal cell cycle control, olfactory dysfunction and neurodegeneration in the adult and aging brain. We emphasize that: (1) CCE in post-mitotic neurons due to loss of cell cycle suppression and/or age-related insults as well as DNA damage can anticipate the development of neurodegenerative lesions and protein aggregates, (2) the age-related decline in SVZ and OE neurogenesis is associated with compensatory pro-survival mechanisms in the aging OB which are interestingly similar to those detected in Alzheimer's disease and Parkinson's disease in humans, and (3) the OB represents a well suitable model to study the early manifestation of age-related defects that may eventually progress into the formation of neurodegenerative lesions and, possibly, spread to the rest of the brain. Such findings may provide a novel approach to the modeling of neurodegenerative diseases in humans from early detection to progression and treatment as well.

Dysfunctional Sensory Modalities, Locus Coeruleus, and Basal Forebrain: Early Determinants that Promote Neuropathogenesis of Cognitive and Memory Decline and Alzheimer's Disease.

PubMed

Daulatzai, Mak Adam

2016-10-01

Sporadic Alzheimer's disease (AD) is a devastating neurodegenerative disorder. It is essential to unravel its etiology and pathogenesis. This should enable us to study the presymptomatic stages of the disease and to analyze and reverse the antemortem behavioral, memory, and cognitive dysfunction. Prima facie, an ongoing chronic vulnerability involving neural insult may lead normal elderly to mild cognitive impairment (MCI) and then to AD. Development of effective preventive and therapeutic strategies to thwart the disease pathology obviously requires a thorough delineation of underlying disruptive neuropathological processes. Our sensory capacity for touch, smell, taste, hearing, and vision declines with advancing age. Declines in different sensory attributes are considered here to be the primary "first-tier pathologies." Olfactory loss is among the first clinical signs of neurodegenerative diseases including AD and Parkinson's disease (PD). Sensory dysfunction in the aged promotes pathological disturbances in the locus coeruleus, basal forebrain, entorhinal cortex, hippocampus, and several key areas of neocortex and brainstem. Hence, sensory dysfunction is the pivotal factor that may upregulate cognitive and memory dysfunction. The age-related constellation of comorbid pathological factors may include apolipoprotein E (APOE) genotype, obesity, diabetes, hypertension, alcohol abuse, head trauma, and obstructive sleep apnea. The concepts and trajectories delineated here are the dynamic pillars of the current hypothesis presented-it postulates that the sensory decline, in conjunction with the above pathologies, is crucial in triggering neurodegeneration and promoting cognitive/memory dysfunction in aging and AD. The application of this thesis can be important in formulating new multifactorial preventive and treatment strategies (suggested here) in order to attenuate cognitive and memory decline and ameliorate pathological dysfunction in aging, MCI, and AD.

Ethological endophenotypes are altered by elevated stress hormone levels in both Huntington's disease and wildtype mice.

PubMed

Mo, Christina; Renoir, Thibault; Hannan, Anthony J

2014-11-01

Huntington's disease (HD) is an autosomal dominant, neurodegenerative disorder with cognitive, psychiatric, motor, neuroendocrine and peripheral dysfunctions. Symptom onset and progression can be closely modeled in HD transgenic mice, which facilitate the search for therapeutics and environmental modulators. In the first investigation of chronic stress in HD, we have previously shown that administering a moderate dose of the stress hormone, corticosterone (CORT) had no effect on short-term memory in wildtype (WT) mice but accelerated the onset of the impairment in male R6/1 HD mice. We now extend this investigation to ethological dysfunctions in HD, which we hypothesized to be more susceptible to CORT treatment compared to the same functions in WT littermates. Both genotypes consumed similar doses of CORT dissolved in drinking water across 6-14 weeks of age and were assessed for olfactory sensitivity, nest-building, saccharin preference as well as vocal responses to sociosexual stimuli. In female HD and WT mice, olfactory sensitivity and saccharin preference were reduced by 2 and 4 weeks of CORT, respectively. In males, there was no effect of CORT on saccharin preference, however the number of vocalizations to a female mouse was transiently increased by CORT-drinking, regardless of genotype. Nest-building was severely impaired in HD mice at an early age, but was unaffected by CORT. Our results suggest that the presence of the HD mutation had no bearing on CORT-induced effects at this dose, suggesting that even moderately elevated stress hormone levels can impair ethological behaviors in both the HD and healthy brain. Copyright © 2014 Elsevier B.V. All rights reserved.

At the interface of sensory and motor dysfunctions and Alzheimer's disease.

PubMed

Albers, Mark W; Gilmore, Grover C; Kaye, Jeffrey; Murphy, Claire; Wingfield, Arthur; Bennett, David A; Boxer, Adam L; Buchman, Aron S; Cruickshanks, Karen J; Devanand, Davangere P; Duffy, Charles J; Gall, Christine M; Gates, George A; Granholm, Ann-Charlotte; Hensch, Takao; Holtzer, Roee; Hyman, Bradley T; Lin, Frank R; McKee, Ann C; Morris, John C; Petersen, Ronald C; Silbert, Lisa C; Struble, Robert G; Trojanowski, John Q; Verghese, Joe; Wilson, Donald A; Xu, Shunbin; Zhang, Li I

2015-01-01

Recent evidence indicates that sensory and motor changes may precede the cognitive symptoms of Alzheimer's disease (AD) by several years and may signify increased risk of developing AD. Traditionally, sensory and motor dysfunctions in aging and AD have been studied separately. To ascertain the evidence supporting the relationship between age-related changes in sensory and motor systems and the development of AD and to facilitate communication between several disciplines, the National Institute on Aging held an exploratory workshop titled "Sensory and Motor Dysfunctions in Aging and AD." The scientific sessions of the workshop focused on age-related and neuropathologic changes in the olfactory, visual, auditory, and motor systems, followed by extensive discussion and hypothesis generation related to the possible links among sensory, cognitive, and motor domains in aging and AD. Based on the data presented and discussed at this workshop, it is clear that sensory and motor regions of the central nervous system are affected by AD pathology and that interventions targeting amelioration of sensory-motor deficits in AD may enhance patient function as AD progresses. Copyright © 2015 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

[Signs and symptoms, etiologies and clinical course of parosmia + in a series of 84 patients].

PubMed

Portier, F; Faulcon, P; Lamblin, B; Bonfils, P

2000-02-01

Eighty-four patients (72% females and 28% males) consulted between January 1995 and January 1998 for olfactory disorders with parosmia (erroneous olfactory response to stimuli). Parosmia occurred immediately after or during the course of acute rhinitis (n=70, 83%), head trauma (n=7, 9%), naso-sinus polyposis (n=5, 6%), chronic rhinitis (n=1) or frontal tumor (n=1). Quantitative and qualitative olfactory disorders were analyzed and products producing the parosmia were identified. The only cases where parosmia regressed concerned patients who developed parosmia after acute rhinitis (n=28 cases, 33%). The prognosis of parosmia appeared to be better when it was a secondary phenomenon: i) the percentage of improvements was higher though not significant (41% versus 26.7% compared with primary parosmia), ii) delay to improvement was shorter (8.4 +/- 2.1 months versus 14.5 +/- 4.4 months for primary parosmia, p<10(-4) ), iii) there were no cases of persistent parosmia where quantitative disorders improved (compared with 7 cases of persistent primary parosmia, p<0.05). In addition, the prognosis of associated quantitative disorders was the same for both primary and secondary parosmia. Only the delay to improvement appeared to be shorter in case of secondary parosomia (though the difference was not significant). Products which produced the parosmic perception were identified by nearly all the patients (85%). The most frequently cited products were coffee, perfume, certain fruits (melon, banana, citric fruits), tobacco or chocolate. All these products contain tannic acid, a water-soluble polyphenol with many biological properties (influence feeding habits and metabolism in the rate, antioxidant and antimutagenic properties). Thus acid tannic could induce parosmic perception due to its antioxidant properties susceptible of integrating the P-450 cytochromes of the mucosal cells or olfactory neuroepithelium supporting cells.

Olfactory Impact of Higher Alcohols on Red Wine Fruity Ester Aroma Expression in Model Solution.

PubMed

Cameleyre, Margaux; Lytra, Georgia; Tempere, Sophie; Barbe, Jean-Christophe

2015-11-11

This study focused on the impact of five higher alcohols on the perception of fruity aroma in red wines. Various aromatic reconstitutions were prepared, consisting of 13 ethyl esters and acetates and 5 higher alcohols, all at the average concentrations found in red wine. These aromatic reconstitutions were prepared in several matrices. Sensory analysis revealed the interesting behavior of certain compounds among the five higher alcohols following their individual addition or omission. The "olfactory threshold" of the fruity pool was evaluated in several matrices: dilute alcohol solution, dilute alcohol solution containing 3-methylbutan-1-ol or butan-1-ol individually, and dilute alcohol solution containing the mixture of five higher alcohols, blended together at various concentrations. The presence of 3-methylbutan-1-ol or butan-1-ol alone led to a significant decrease in the "olfactory threshold" of the fruity reconstitution, whereas the mixture of alcohols raised the olfactory threshold. Sensory profiles highlighted changes in the perception of fruity nuances in the presence of the mixture of higher alcohols, with specific perceptive interactions, including a relevant masking effect on fresh- and jammy-fruit notes of the fruity mixture in both dilute alcohol solution and dearomatized red wine matrices. When either 3-methylbutan-1-ol or butan-1-ol was added to the fruity reconstitution in dilute alcohol solution, an enhancement of butyric notes was reported with 3-methylbutan-1-ol and fresh- and jammy-fruit with butan-1-ol. This study, the first to focus on the impact of higher alcohols on fruity aromatic expression, revealed that these compounds participate, both quantitatively and qualitatively, in masking fruity aroma perception in a model fruity wine mixture.

“Unclassical” Combination of Smell Dysfunction, Altered Abdominal Nociception and Human Hypertension Associated “Classical” Adrenal-Augmentation

PubMed Central

Leon-Ariza, Daniel S.; Leon-Ariza, Juan S.; Leon-Sarmiento, Fidias E.

2015-01-01

We report a 33-year-old female patient, who arrived to the emergency ward with an abdominal pain that suddenly started 10 days before admission. Simultaneously, the patient developed sudden arterial hypertension and smell disturbances. Conventional medical treatment for pain and arterial hypertension was effortless. Laboratory tests ruled out pancreatitis. Metanephrines in her urine were also normal. A dual-phase intravenous contrast computed tomography of the abdomen showed a large mass within left adrenal gland. Adrenocortical adenoma was diagnosed. The mass was not hypervascularized but positive for synaptophysin and chromogranin A. Importantly, these proteins are heavily involved with acetylcholine metabolism. The triad of olfactory disorders, pain and arterial hypertension normalized after surgically extracting the adrenal mass. To our knowledge, this medical case is the first reported patient exhibiting immediate recovery of such unclassical triad of local and remote findings. The function and dysfunction of key nanocholinergic pathways involved with smell, blood pressure and nociception would explain the pathophysiology of this unique medical case. PMID:26688704

Zincergic innervation from the anterior olfactory nucleus to the olfactory bulb displays plastic responses after mitral cell loss.

PubMed

Airado, Carmen; Gómez, Carmela; Recio, Javier S; Baltanás, Fernando C; Weruaga, Eduardo; Alonso, José R

2008-12-01

Zinc ions are selectively accumulated in certain neurons (zinc-enriched neurons). The mouse olfactory bulb is richly innervated by zinc-enriched terminals. Here, the plasticity of the zincergic system was studied in the olfactory bulb of the Purkinje Cell Degeneration mutant mouse, an animal with specific postnatal neurodegeneration of the main projection neurons of the olfactory bulb. The analysis focused particularly on the anterior olfactory nucleus since most centrifugal afferents coming to the olfactory bulb arise from this structure. Zinc-enriched terminals in the olfactory bulb and zinc-enriched somata in the anterior olfactory nucleus were visualized after selenite injections. Immunohistochemistry against the vesicular zinc transporter was also carried out to confirm the distribution pattern of zinc-enriched terminals in the olfactory bulb. The mutant mice showed a clear reorganization of zincergic centrifugal projections from the anterior olfactory nucleus to the olfactory bulb. First, all zincergic contralateral neurons projecting to the olfactory bulb were absent in the mutant mice. Second, a significant increase in the number of stained somata was detected in the ipsilateral anterior olfactory nucleus. Since no noticeable changes were observed in the zinc-enriched terminals in the olfactory bulb, it is conceivable that mitral cell loss could induce a reorganization of zinc-enriched projections coming from the anterior olfactory nucleus, probably directed at balancing the global zincergic centrifugal modulation. These results show that zincergic anterior olfactory nucleus cells projecting to the olfactory bulb undergo plastic changes to adapt to the loss of mitral cells in the olfactory bulb of Purkinje Cell Degeneration mutant mice.

Olfactory Perceptual Learning Requires Action of Noradrenaline in the Olfactory Bulb: Comparison with Olfactory Associative Learning

ERIC Educational Resources Information Center

Vinera, Jennifer; Kermen, Florence; Sacquet, Joëlle; Didier, Anne; Mandairon, Nathalie; Richard, Marion

2015-01-01

Noradrenaline contributes to olfactory-guided behaviors but its role in olfactory learning during adulthood is poorly documented. We investigated its implication in olfactory associative and perceptual learning using local infusion of mixed a1-ß adrenergic receptor antagonist (labetalol) in the adult mouse olfactory bulb. We reported that…

Aging results in reduced epidermal growth factor receptor signaling, diminished olfactory neurogenesis, and deficits in fine olfactory discrimination.

PubMed

Enwere, Emeka; Shingo, Tetsuro; Gregg, Christopher; Fujikawa, Hirokazu; Ohta, Shigeki; Weiss, Samuel

2004-09-22

Previous studies demonstrating olfactory interneuron involvement in olfactory discrimination and decreased proliferation in the forebrain subventricular zone with age led us to ask whether olfactory neurogenesis and, consequently, olfactory discrimination were impaired in aged mice. Pulse labeling showed that aged mice (24 months of age) had fewer new interneurons in the olfactory bulb than did young adult (2 months of age) mice. However, the aged mice had more olfactory interneurons in total than their younger counterparts. Aged mice exhibited no differences from young adult mice in their ability to discriminate between two discrete odors but were significantly poorer at performing discriminations between similar odors (fine olfactory discrimination). Leukemia inhibitory factor receptor heterozygote mice, which have less neurogenesis and fewer olfactory interneurons than their wild-type counterparts, performed more poorly at fine olfactory discrimination than the wild types, suggesting that olfactory neurogenesis, rather than the total number of interneurons, was responsible for fine olfactory discrimination. Immunohistochemistry and Western blot analyses revealed a selective reduction in expression levels of epidermal growth factor (EGF) receptor (EGFR) signaling elements in the aged forebrain subventricular zone. Waved-1 mutant mice, which express reduced quantities of transforming growth factor-alpha, the predominant EGFR ligand in adulthood, phenocopy aged mice in olfactory neurogenesis and performance on fine olfactory discrimination tasks. These results suggest that the impairment in fine olfactory discrimination with age may result from a reduction in EGF-dependent olfactory neurogenesis.

Immunocytochemistry of the olfactory marker protein.

PubMed

Monti-Graziadei, G A; Margolis, F L; Harding, J W; Graziadei, P P

1977-12-01

The olfactory marker protein has been localized, by means of immunohistochemical techniques in the primary olfactory neurons of mice. The olfactory marker protein is not present in the staminal cells of the olfactory neuroepithelium, and the protein may be regarded as indicative of the functional stage of the neurons. Our data indicate that the olfactory marker protein is present in the synaptic terminals of the olfactory neurons at the level of the olfactory bulb glomeruli. The postsynaptic profiles of both mitral and periglomerular cells are negative.

[Posttraumatic anosmia: olfactory event related potentials and MRI evaluation].

PubMed

Liu, Jian-Feng; You, Hui; Ni, Dao-Feng; Zhang, Qiu-Hang; Yang, Da-Zhang; Wang, Na-Ya

2008-03-01

Using olfactory event related potentials (OERP) and magnetic resonance to evaluate olfactory function in patients with posttraumatic anosmia. Twenty four patients with posttraumatic anosmia were reviewed retrospectively. A thorough medical history, physical examination, nasal endoscopy, T&T olfactory testing, olfactory event-related potentials, brain computed tomography scan and magnetic resonance image of olfactory pathway were performed in all patients. Subjective olfactory testing indicated 20 of 24 patients were birhinal anosmia, 2 with right nostril anosmia and left impairment, 2 with left anosmia and right normal. No OERP were obtained in 24 (20 were birhinal, 4 was monorhinal), except 4 cases with single nostril. Magnetic resonance imaging revealed the injures to the olfactory bulbs (100%), rectus gyrus (91.7%), orbital gyrus (67%), olfactory tracts (8%) and temporal lobes (8%). OERP can objectively evaluate posttraumatic olfactory function, and magnetic resonance of olfactory pathway can precisely identify the location and extent of injures.

A potential link among biogenic amines-based pesticides, learning and memory, and colony collapse disorder: a unique hypothesis.

PubMed

Farooqui, Tahira

2013-01-01

Pesticides are substances that have been widely used throughout the world to kill, repel, or control organisms such as certain forms of plants or animals considered as pests. Depending on their type, dose, and persistence in the environment, they can have impact even on non-target species such as beneficial insects (honeybees) in different ways, including reduction in their survival rate and interference with their reproduction process. Honeybee Apis mellifera is a major pollinator and has substantial economical and ecological values. Colony collapse disorder (CCD) is a mysterious phenomenon in which adult honeybee workers suddenly abandon from their hives, leaving behind food, brood, and queen. It is lately drawing a lot of attention due to pollination crisis as well as global agriculture and medical demands. If the problem of CCD is not resolved soon enough, this could have a major impact on food industry affecting world's economy a big time. Causes of CCD are not known. In this overview, I discuss CCD, biogenic amines-based-pesticides (neonicotinoids and formamidines), and their disruptive effects on biogenic amine signaling causing olfactory dysfunction in honeybees. According to my hypothesis, chronic exposure of biogenic amines-based-pesticides to honeybee foragers in hives and agricultural fields can disrupt neural cholinergic and octopaminergic signaling. Abnormality in biogenic amines-mediated neuronal signaling impairs their olfactory learning and memory, therefore foragers do not return to their hive - a possible cause of CCD. This overview is an attempt to discuss a hypothetical link among biogenic amines-based pesticides, olfactory learning and memory, and CCD. Copyright © 2012 Elsevier Ltd. All rights reserved.

Higher blood harmane (1-methyl-9H-pyrido[3,4-b]indole) concentrations correlate with lower olfactory scores in essential tremor.

PubMed

Louis, Elan D; Rios, Eileen; Pellegrino, Kathryn M; Jiang, Wendy; Factor-Litvak, Pam; Zheng, Wei

2008-05-01

Harmane (1-methyl-9H-pyrido[3,4-b]indole), a neurotoxin, may be an environmental risk factor for essential tremor (ET). Harmane and related chemicals are toxic to the cerebellum. Whether it is through this mechanism (cerebellar toxicity) that harmane leads to ET is unknown. Impaired olfaction may be a feature of cerebellar disease. To determine whether blood harmane concentrations correlate with olfactory test scores in patients with ET. Blood harmane concentrations were quantified using high performance liquid chromatography. Odor identification testing was performed with the University of Pennsylvania Smell Identification Test (UPSIT). In 83 ET cases, higher log blood harmane concentration was correlated with lower UPSIT score (rho=-0.46, p<0.001). 25/40 (62.5%) cases with high log blood harmane concentration (based on a median split) had low UPSIT scores (based on a median split) vs. 12/43 (27.9%) ET cases with low log blood harmane concentration (adjusted odd ratios (OR) 4.04, 95% confidence intervals (CI) 1.42-11.50, p=0.009). When compared with the low log blood harmane tertile, the odds of olfactory dysfunction were 2.64 times higher in cases in the middle tertile and 10.95 times higher in cases in the high tertile. In 69 control subjects, higher log blood harmane concentration was not correlated with lower UPSIT score (rho=0.12, p=0.32). Blood harmane concentrations were correlated with UPSIT scores in ET cases but not controls. These analyses set the stage for postmortem studies to further explore the role of harmane as a cerebellar toxin in ET.

Higher Blood Harmane (1-Methyl-9h-Pyrido[3,4-B]Indole) Concentrations Correlate With Lower Olfactory Scores In Essential Tremor

PubMed Central

Louis, Elan D.; Rios, Eileen; Pellegrino, Kathryn M.; Jiang, Wendy; Factor-Litvak, Pam; Zheng, Wei

2008-01-01

Background Harmane (1-methyl-9H-pyrido[3,4-b]indole), a neurotoxin, may be an environmental risk factor for essential tremor (ET). Harmane and related chemicals are toxic to the cerebellum. Whether it is through this mechanism (cerebellar toxicity) that harmane leads to ET is unknown. Impaired olfaction may be a feature of cerebellar disease. Objective To determine whether blood harmane concentrations correlate with olfactory test scores in patients with ET. Methods Blood harmane concentrations were quantified using high performance liquid chromatography. Odor identification testing was performed with the University of Pennsylvania Smell Identification Test (UPSIT). Results In 83 ET cases, higher log blood harmane concentration was correlated with lower UPSIT score (rho = −0.46, p < 0.001). 25/40 (62.5%) cases with high log blood harmane concentration (based on a median split) had low UPSIT scores (based on a median split) vs. 12/43 (27.9%) ET cases with low log blood harmane concentration (adjusted OR 4.04, 95% CI 1.42 – 11.50, p = 0.009). When compared with the low log blood harmane tertile, the odds of olfactory dysfunction were 2.64 times higher in cases in the middle tertile and 10.95 times higher in cases in the high tertile. In 69 control subjects, higher log blood harmane concentration was not correlated with lower UPSIT score (rho = 0.12, p = 0.32). Conclusions Blood harmane concentrations were correlated with UPSIT scores in ET cases but not controls. These analyses set the stage for postmortem studies to further explore the role of harmane as a cerebellar toxin in ET. PMID:18417221

Neurotoxicity following acute inhalation of aerosols generated during resistance spot weld-bonding of carbon steel.

PubMed

Sriram, Krishnan; Jefferson, Amy M; Lin, Gary X; Afshari, Aliakbar; Zeidler-Erdely, Patti C; Meighan, Terence G; McKinney, Walter; Jackson, Mark; Cumpston, Amy; Cumpston, Jared L; Leonard, Howard D; Frazer, David G; Antonini, James M

2014-10-01

Welding generates complex metal aerosols, inhalation of which is linked to adverse health effects among welders. An important health concern of welding fume (WF) exposure is neurological dysfunction akin to Parkinson's disease (PD). Some applications in manufacturing industry employ a variant welding technology known as "weld-bonding" that utilizes resistance spot welding, in combination with adhesives, for metal-to-metal welding. The presence of adhesives raises additional concerns about worker exposure to potentially toxic components like Methyl Methacrylate, Bisphenol A and volatile organic compounds (VOCs). Here, we investigated the potential neurotoxicological effects of exposure to welding aerosols generated during weld-bonding. Male Sprague-Dawley rats were exposed (25 mg/m³ targeted concentration; 4 h/day × 13 days) by whole-body inhalation to filtered air or aerosols generated by either weld-bonding with sparking (high metal, low VOCs; HM) or without sparking (low metal; high VOCs; LM). Fumes generated under these conditions exhibited complex aerosols that contained both metal oxide particulates and VOCs. LM aerosols contained a greater fraction of VOCs than HM, which comprised largely metal particulates of ultrafine morphology. Short-term exposure to LM aerosols caused distinct changes in the levels of the neurotransmitters, dopamine (DA) and serotonin (5-HT), in various brain areas examined. LM aerosols also specifically decreased the mRNA expression of the olfactory marker protein (Omp) and tyrosine hydroxylase (Th) in the olfactory bulb. Consistent with the decrease in Th, LM also reduced the expression of dopamine transporter (Slc6a3; Dat), as well as, dopamine D2 receptor (Drd2) in the olfactory bulb. In contrast, HM aerosols induced the expression of Th and dopamine D5 receptor (Drd5) mRNAs, elicited neuroinflammation and blood-brain barrier-related changes in the olfactory bulb, but did not alter the expression of Omp. Our findings divulge the differential effects of LM and HM aerosols in the brain and suggest that exposure to weld-bonding aerosols can potentially elicit neurotoxicity following a short-term exposure. However, further investigations are warranted to determine if the aerosols generated by weld-bonding can contribute to persistent long-term neurological deficits and/or neurodegeneration.

“Till Death Do Us Part”: A Potential Irreversible Link Between Aberrant Cell Cycle Control and Neurodegeneration in the Adult Olfactory Bulb

PubMed Central

Omais, Saad; Jaafar, Carine; Ghanem, Noël

2018-01-01

Adult neurogenesis (AN) is an ongoing developmental process that generates newborn neurons in the olfactory bulb (OB) and the hippocampus (Hi) throughout life and significantly contributes to brain plasticity. Adult neural stem and progenitor cells (aNSPCs) are relatively limited in number and fate and are spatially restricted to the subventricular zone (SVZ) and the subgranular zone (SGZ). During AN, the distinct roles played by cell cycle proteins extend beyond cell cycle control and constitute key regulatory mechanisms involved in neuronal maturation and survival. Importantly, aberrant cell cycle re-entry (CCE) in post-mitotic neurons has been strongly linked to the abnormal pathophysiology in rodent models of neurodegenerative diseases with potential implications on the etiology and progression of such diseases in humans. Here, we present an overview of AN in the SVZ-OB and olfactory epithelium (OE) in mice and humans followed by a comprehensive update of the distinct roles played by cell cycle proteins including major tumors suppressor genes in various steps during neurogenesis. We also discuss accumulating evidence underlining a strong link between abnormal cell cycle control, olfactory dysfunction and neurodegeneration in the adult and aging brain. We emphasize that: (1) CCE in post-mitotic neurons due to loss of cell cycle suppression and/or age-related insults as well as DNA damage can anticipate the development of neurodegenerative lesions and protein aggregates, (2) the age-related decline in SVZ and OE neurogenesis is associated with compensatory pro-survival mechanisms in the aging OB which are interestingly similar to those detected in Alzheimer's disease and Parkinson's disease in humans, and (3) the OB represents a well suitable model to study the early manifestation of age-related defects that may eventually progress into the formation of neurodegenerative lesions and, possibly, spread to the rest of the brain. Such findings may provide a novel approach to the modeling of neurodegenerative diseases in humans from early detection to progression and treatment as well. PMID:29593485

Association Between Olfactory Dysfunction and Amnestic Mild Cognitive Impairment and Alzheimer Disease Dementia.

PubMed

Roberts, Rosebud O; Christianson, Teresa J H; Kremers, Walter K; Mielke, Michelle M; Machulda, Mary M; Vassilaki, Maria; Alhurani, Rabe E; Geda, Yonas E; Knopman, David S; Petersen, Ronald C

2016-01-01

To increase the opportunity to delay or prevent mild cognitive impairment (MCI) or Alzheimer disease (AD) dementia, markers of early detection are essential. Olfactory impairment may be an important clinical marker and predictor of these conditions and may help identify persons at increased risk. To examine associations of impaired olfaction with incident MCI subtypes and progression from MCI subtypes to AD dementia. Participants enrolled in the population-based, prospective Mayo Clinic Study of Aging between 2004 and 2010 were clinically evaluated at baseline and every 15 months through 2014. Participants (N = 1630) were classified as having normal cognition, MCI (amnestic MCI [aMCI] and nonamnestic MCI [naMCI]), and dementia. We administered the Brief Smell Identification Test (B-SIT) to assess olfactory function. Mild cognitive impairment, AD dementia, and longitudinal change in cognitive performance measures. Of the 1630 participants who were cognitively normal at the time of the smell test, 33 died before follow-up and 167 were lost to follow-up. Among the 1430 cognitively normal participants included, the mean (SD) age was 79.5 (5.3) years, 49.4% were men, the mean duration of education was 14.3 years, and 25.4% were APOE ε4 carriers. Over a mean 3.5 years of follow-up, there were 250 incident cases of MCI among 1430 cognitively normal participants. We observed an association between decreasing olfactory identification, as measured by a decrease in the number of correct responses in B-SIT score, and an increased risk of aMCI. Compared with the upper B-SIT quartile (quartile [Q] 4, best scores), hazard ratios (HRs) (95% CI) were 1.12 (0.65-1.92) for Q3 (P = .68); 1.95 (1.25-3.03) for Q2 (P = .003); and 2.18 (1.36-3.51) for Q1 (P = .001) (worst scores; P for trend <.001) after adjustment for sex and education, with age as the time scale. There was no association with naMCI. There were 64 incident dementia cases among 221 prevalent MCI cases. The B-SIT score also predicted progression from aMCI to AD dementia, with a significant dose-response with worsening B-SIT quartiles. Compared with Q4, HR (95% CI) estimates were 3.02 (1.06-8.57) for Q3 (P = .04); 3.63 (1.19-11.10) for Q2 (P = .02); and 5.20 (1.90-14.20) for Q1 (P = .001). After adjusting for key predictors of MCI risk, B-SIT (as a continuous measure) remained a significant predictor of MCI (HR, 1.10 [95% CI, 1.04-1.16]; P < .001) and improved the model concordance. Olfactory impairment is associated with incident aMCI and progression from aMCI to AD dementia. These findings are consistent with previous studies that have reported associations of olfactory impairment with cognitive impairment in late life and suggest that olfactory tests have potential utility for screening for MCI and MCI that is likely to progress.

Odor-evoked inhibition of olfactory sensory neurons drives olfactory perception in Drosophila.

PubMed

Cao, Li-Hui; Yang, Dong; Wu, Wei; Zeng, Xiankun; Jing, Bi-Yang; Li, Meng-Tong; Qin, Shanshan; Tang, Chao; Tu, Yuhai; Luo, Dong-Gen

2017-11-07

Inhibitory response occurs throughout the nervous system, including the peripheral olfactory system. While odor-evoked excitation in peripheral olfactory cells is known to encode odor information, the molecular mechanism and functional roles of odor-evoked inhibition remain largely unknown. Here, we examined Drosophila olfactory sensory neurons and found that inhibitory odors triggered outward receptor currents by reducing the constitutive activities of odorant receptors, inhibiting the basal spike firing in olfactory sensory neurons. Remarkably, this odor-evoked inhibition of olfactory sensory neurons elicited by itself a full range of olfactory behaviors from attraction to avoidance, as did odor-evoked olfactory sensory neuron excitation. These results indicated that peripheral inhibition is comparable to excitation in encoding sensory signals rather than merely regulating excitation. Furthermore, we demonstrated that a bidirectional code with both odor-evoked inhibition and excitation in single olfactory sensory neurons increases the odor-coding capacity, providing a means of efficient sensory encoding.

[Clinical and magnetic resonance imaging characteristics of isolated congenital anosmia].

PubMed

Liu, Jian-feng; Wang, Jian; You, Hui; Ni, Dao-feng; Yang, Da-zhang

2010-05-25

To report a series of patients with isolated congenital anosmia and summarize their clinical and magnetic resonance imaging (MRI) characteristics. Twenty patients with isolated congenital anosmia were reviewed retrospectively. A thorough medical and chemosensory history, physical examination, nasal endoscopy, T&T olfactory testing, olfactory event-related potentials, sinonasal computed tomography scan and magnetic resonance image of olfactory pathway were performed in all patients. Neither ENT physical examination nor nasal endoscopy was remarkable. Subjective olfactory testing indicated all of them were of anosmia. No olfactory event-related potentials to maximal stimulus were obtained. Computed tomography scan was normal. MRI revealed the absence of olfactory bulbs and tracts in all cases. And hypoplasia or aplasia of olfactory sulcus was found in all cases. All the patients had normal sex hormone level. The diagnosis of isolated congenital anosmia is established on chief complaints, physical examination, olfactory testing and olfactory imaging. MRI of olfactory pathway is indispensable.

Rationalization of the Irrational Neuropathologic Basis of Hypothyroidism-Olfaction Disorders Paradox: Experimental Study.

PubMed

Aydin, Nazan; Ramazanoglu, Leyla; Onen, Mehmet Resid; Yilmaz, Ilhan; Aydin, Mehmet Dumlu; Altinkaynak, Konca; Calik, Muhammet; Kanat, Ayhan

2017-11-01

Hypothyroidism is defined as an underactive thyroid gland and one of the reasons for inadequate stimulation of thyroid is dysfunction of the hormone regulating brain centers. Olfaction disorders have been considered as a problem in hypothyroidism. It has been hypothesized that olfaction disorders reduce olfactory stimulation and diminished olfactory stimulus may trigger hypothyroidism. In this study, an examination was made of the thyroid hormone levels, histologic features of thyroid glands, and vagal nerve network degradation in an experimental animal model of olfactory bulbectomy (OBX). A total of 25 rats were divided into control (n = 5), SHAM (n = 5), and OBX (n = 15) groups and were followed up for 8 weeks. Thyroid hormone levels were measured before (1 time), during the experiment (1 time/month) and the animals were decapitated. The olfactory bulbs, dorsal motor nucleus of the vagal nerves, and thyroid gland sections were stained with hematoxylin-eosin and tunnel dye to determine OBX-related damage. Specimens were analyzed stereologically to evaluate neuron density of the vagal nucleus and hormone-filled total follicle volume (TFV) per cubic centimeter, and these were statistically compared with thyroid hormone levels. The mean degenerated neuron density of the vagal nucleus was 21 ± 8/mm 3 . TFV and triiodothyronine (T 3 )-thyroxine (T 4 ) levels were measured as TFV, (312 ± 91) × 10 6 μm 3 /cm 3 ; T 3 , 105 μg/dl; T 4 , 1.89 μg/dl in control (group I). Mean degenerated neuron density, 56 ± 12/mm 3 ; TFV, (284 ± 69) × 10 6 μm 3 /cm 3 ; T 3 , 103 μg/dl; T 4 , 1.85 μg/dl in SHAM (group II). Mean degenerated neuron density, 235 ± 64/mm 3 ; TFV, (193 ± 34) × 10 6 μm 3 /cm 3 ; T 3 , 86 μg/dl; T 4 , 1.37 μg/dl in the OBX group (group III). The TFV were significantly diminished because of apoptotic degradation in olfactory bulbs and thyroid gland with decreased T 3 - T 4 levels with increased thyroid-stimulating hormone levels in OBX-applied animals of subarachnoid hemorrhage (P < 0.005). The results suggested that diminished hormone secretion as a result of thyroid gland degradation results in both olfaction loss and vagal complex degeneration in OBX animals, contrary to the common belief that anosmia results from hypothyroidism. Copyright © 2017 Elsevier Inc. All rights reserved.

Clinical features of schizophrenia in a woman with hyperandrogenism.

PubMed Central

Kopala, L C; Lewine, R; Good, K P; Fluker, M; Martzke, J S; Lapointe, J S; Honer, W G

1997-01-01

Ample evidence supports sex differences in the clinical features of schizophrenia. In this regard, estrogen may contribute to later onset and less severe course of illness in women. Direct investigation of hormonal status in schizophrenia is extremely difficult. The present report documents the clinical features of schizophrenia in a young woman with long-standing hyperandrogenism related to polycystic ovarian disease. We postulate that hyperandrogenism contributed to a relatively early onset, olfactory dysfunction, and other clinical features of schizophrenia more commonly associated with men. Additionally, acute estrogen depletion following cessation of oral contraceptives may have precipitated psychosis, while recommencement of oral contraceptives could have contributed to subsequent improvement in symptoms. PMID:9002393

Olfactory discrimination deficits in mice lacking the dopamine transporter or the D2 dopamine receptor.

PubMed

Tillerson, Jennifer L; Caudle, W Michael; Parent, Jack M; Gong, C; Schallert, Timothy; Miller, Gary W

2006-09-15

Previous pharmacological studies have implicated dopamine as a modulator of olfactory bulb processing. Several disorders characterized by altered dopamine homeostasis in olfaction-related brain regions display olfactory deficits. To further characterize the role of dopamine in olfactory processing, we subjected dopamine transporter knockout mice (DAT -/-) and dopamine receptor 2 knockout mice (D2 -/-) to a battery of olfactory tests. In addition to behavioral characterization, several neurochemical markers of olfactory bulb integrity and function were examined. DAT -/- mice displayed an olfactory discrimination deficit, but did not differ detectably from DAT wildtype (DAT +/+) mice in odor habituation, olfactory sensitivity, or odor recognition memory. Neurochemically, DAT -/- mice have decreased D2 receptor staining in the periglomerular layer of the olfactory bulb and increased tyrosine hydroxylase immunoreactivity compared to DAT +/+ controls. D2 -/- mice exhibited the same olfactory deficit as the DAT -/- mice, further supporting the role of dopamine at the D2 synapse in olfactory discrimination processing. The findings presented in this paper reinforce the functional significance of dopamine and more specifically the D2 receptor in olfactory discrimination and may help explain the behavioral phenotype in the DAT and D2 knockout mice.

Morphological and electrophysiological examination of olfactory sensory neurons during the early developmental prolarval stage of the sea lamprey Petromyzon marinus L

USGS Publications Warehouse

Zielinski, B.S.; Fredricks, Keith; McDonald, R.; Zaidi, A.U.

2005-01-01

This study examined olfactory sensory neuron morphology and physiological responsiveness in newly hatched sea lamprey, Petromyzon marinus L. These prolarvae hatch shortly after neural tube formation, and stay within nests for approximately 18 days, before moving downstream to silty areas where they burrow, feed and pass to the larval stage. To explore the possibility that the olfactory system is functioning during this prolarval stage, morphological and physiological development of olfactory sensory neurons was examined. The nasal cavity contained an olfactory epithelium with ciliated olfactory sensory neurons. Axons formed aggregates in the basal portion of the olfactory epithelium and spanned the narrow distance between the olfactory epithelium and the brain. The presence of asymmetric synapses with agranular vesicles within fibers in the brain, adjacent to the olfactory epithelium suggests that there was synaptic connectivity between olfactory sensory axons and the brain. Neural recordings from the surface of the olfactory epithelium showed responses following the application of L-arginine, taurocholic acid, petromyzonol sulfate (a lamprey migratory pheromone), and water conditioned by conspecifics. These results suggest that lampreys may respond to olfactory sensory input during the prolarval stage. ?? 2006 Springer Science + Business Media, LLC.

The development of the olfactory organs in newly hatched monotremes and neonate marsupials

PubMed Central

Schneider, Nanette Yvette

2011-01-01

Olfactory cues are thought to play a crucial role in the detection of the milk source at birth in mammals. It has been shown that a marsupial, the tammar wallaby, can detect olfactory cues from its mother's pouch at birth. This study investigates whether the main olfactory and accessory olfactory system are similarly well developed in other marsupials and monotremes at birth/hatching as in the tammar. Sections of the head of various marsupial and two monotreme species were investigated by light microscopy. Both olfactory systems were less well developed in the kowari and Eastern quoll. No olfactory or vomeronasal or terminal nerves could be observed; the main olfactory bulb (MOB) had only two layers while no accessory olfactory bulb or ganglion terminale were visible. All other investigated marsupials and monotremes showed further developed olfactory systems with olfactory, vomeronasal and terminal nerves, a three-layered MOB, and in the marsupials a prominent ganglion terminale. The main olfactory system was further developed than the accessory olfactory system in all species investigated. The olfactory systems were the least developed in species in which the mother's birth position removed most of the difficulty in reaching the teat, placing the neonate directly in the pouch. In monotremes they were the furthest developed as Bowman glands were found underlying the main olfactory epithelium. This may reflect the need to locate the milk field each time they drink as they cannot permanently attach to it, unlike therian mammals. While it still needs to be determined how an odour signal could be further processed in the brain, this study suggests that marsupials and monotremes possess well enough developed olfactory systems to be able to detect an odour cue from the mammary area at birth/hatching. It is therefore likely that neonate marsupials and newly hatched monotremes find their way to the milk source using olfactory cues, as has been previously suggested for the marsupial tammar wallaby, rabbits, rats and other eutherians. PMID:21592102

Therapy of a couple with a bipolar spouse.

PubMed

Witusik, Andrzej; Pietras, Tadeusz

2017-10-23

Qualitative analysis of therapy of a couple with a partner who has bipolar disorder is an important research paradigm in contemporary psychotherapy of mental disorders.The qualitative method of the study is important both from the cognitive point of view and for the evaluation of the therapeutic efficacy in the individual, idiographical aspect. The aim of the study is a qualitative analysis of the therapeutic process of a couple in which one partner suffers from bipolar affective disorder. The study of the couple therapy process utilized the qualitative research methodology using variouspsychotherapeutic paradigms indicating the interrelationships that exist between relapses of the disease and functioning of the couple. The importance of triangulation processes, inheritance of transgenerational myths and dysfunctional cognitive patterns in the functional destabilization of a couple with one partner suffering from bipolar affective disorder was indicated. The study of the couple therapy process utilized the qualitative research methodology using variouspsychotherapeutic paradigms indicating the interrelationships that exist between relapses of the disease and functioning of the couple. The importance of triangulation processes, inheritance of transgenerational myths and dysfunctional cognitive patterns in the functional destabilization of a couple with one partner suffering from bipolar affective disorder was indicated. The dysfunctionality of the discussed couple is largely due to the effects of bipolar disorder and related disturbances on marital functioning. The spectrum of autism in the child is probably related both to the genetic strain of predisposition to psychiatric disorders and to the dysfunctionality of the parental dyad. The presence of bipolar affective disorder in the partner's family is also a genetic burden. The wife's aggression represents probably a syndrome of adaptation to disease in the family. Aggression plays a morphostatic role in the couple integrity.In both families of origin of the spouses, the transgeneration myth placed the woman in the position of a strong and family-oriented person.

Morphometric and ultrastructural comparison of the olfactory system in elasmobranchs: the significance of structure-function relationships based on phylogeny and ecology.

PubMed

Schluessel, Vera; Bennett, Michael B; Bleckmann, Horst; Blomberg, Simon; Collin, Shaun P

2008-11-01

This study investigated the relationship between olfactory morphology, habitat occupancy, and lifestyle in 21 elasmobranch species in a phylogenetic context. Four measures of olfactory capability, that is, the number of olfactory lamellae, the surface area of the olfactory epithelium, the mass of the olfactory bulb, and the mass of the olfactory rosette were compared between individual species and groups, comprised of species with similar habitat and/or lifestyle. Statistical analyses using generalized least squares phylogenetic regression revealed that bentho-pelagic sharks and rays possess significantly more olfactory lamellae and larger sensory epithelial surface areas than benthic species. There was no significant correlation between either olfactory bulb or rosette mass and habitat type. There was also no significant difference between the number of lamellae or the size of the sensory surface area in groups comprised of species with similar diets, that is, groups preying predominantly on crustaceans, cephalopods, echinoderms, polychaetes, molluscs, or teleosts. However, some groups had significantly larger olfactory bulb or rosette masses than others. There was little evidence to support a correlation between phylogeny and morphology, indicating that differences in olfactory capabilities are the result of functional rather than phylogenetic adaptations. All olfactory epithelia exhibited microvilli and cilia, with microvilli in both nonsensory and sensory areas, and cilia only in sensory areas. Cilia over the sensory epithelia originated from supporting cells. In contrast to teleosts, which possess ciliated and microvillous olfactory receptor types, no ciliated olfactory receptor cells were observed. This is the first comprehensive study comparing olfactory morphology to several aspects of elasmobranch ecology in a phylogenetic context.

The physiological basics of the olfactory neuro-epithelium.

PubMed

Watelet, J B; Katotomichelakis, M; Eloy, P; Danielidis, V

2009-01-01

All living organisms can detect and identify chemical substances in their environment. The olfactory epithelium is covered by a mucus layer which is essential for the function of the olfactory neurons that are directly connected to the brain through the cribriform plate. However, little is known about the composition of this mucus in humans and its significance for the diagnosis of olfactory disorders. The olfactory epithelium consists of four primary cell types, including the olfactory receptor cells essential for odour transduction. This review examines the anatomical, histological and physiological fundamentals of olfactory mucosa. Particular attention is paid to the biochemical environment of the olfactory mucosa that regulates both peri-receptor events and several protective functions.

A Closer Look at Acid-Base Olfactory Titrations

ERIC Educational Resources Information Center

Neppel, Kerry; Oliver-Hoyo, Maria T.; Queen, Connie; Reed, Nicole

2005-01-01

Olfactory titrations using raw onions and eugenol as acid-base indicators are reported. An in-depth investigation on olfactory titrations is presented to include requirements for potential olfactory indicators and protocols for using garlic, onions, and vanillin as acid-base olfactory indicators are tested.

Novel spiroimidazopyridine derivative SAK3 improves methimazole-induced cognitive deficits in mice.

PubMed

Noreen, Husain; Yabuki, Yasushi; Fukunaga, Kohji

2017-09-01

Methimazole (MMI) is a first-line therapy used to manage hyperthyroidism and Graves' disease. Despite its therapeutic benefit, chronic MMI administration can lead to hypothyroidism and perturb brain homeostasis in patients, resulting in neuropsychiatric disorders such as depression and cognitive dysfunction. We recently developed the spiroimidazopyridine derivative SAK3 as cognitive enhancer; however, mechanisms underlying its activity remained unclear. Here, we show that SAK3 potentially improves cognitive impairment seen following MMI-induced hypothyroidism. Twenty-four hours after MMI (75 mg/kg, i.p.) treatment, we administered SAK3 (0.1, 0.5 and 1 mg/kg, p.o.) to mice daily for 7 days. MMI treatment alone disrupted olfactory bulb (OB) glomerular structure, as assessed by staining with the olfactory marker protein (OMP), reduced the number of choline acetyl transferase (ChAT)-immunoreactive neurons in medial septum (MS), and significantly impaired cognition. SAK3 (0.5 and 1 mg/kg, p.o.) administration significantly restored the number of cholinergic MS neurons in MMI-treated mice, and SAK3 treatment at a higher dose significantly improved cognitive deficits seen in MMI-treated control mice. Overall, our study suggests that SAK3 treatment could antagonize such impairment in patients with hypothyroidism. Copyright © 2017 Elsevier Ltd. All rights reserved.

Self-esteem as an important factor in quality of life and depressive symptoms in anosmia: A pilot study.

PubMed

Kollndorfer, K; Reichert, J L; Brückler, B; Hinterleitner, V; Schöpf, V

2017-12-01

Previous research has reported a negative impact of olfactory dysfunction on quality of life (QoL) and depressive symptoms. As self-esteem was identified as a contributing factor to depression, this study aimed to investigate QoL, depressive symptoms and self-esteem in patients with smell loss. Prospective controlled study. Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, in co-operation with the Department of Ear, Nose and Throat Diseases, Medical University of Vienna, Austria. Twenty-two anosmic patients (12 females, 10 males) and 25 healthy controls (15 females, 10 males) participated in this study. Olfactory performance was assessed using the Sniffin' Sticks battery. In addition, psychological questionnaires that covered the topics quality of life (WHOQOL-BREF), depressive symptoms (BDI-II) and self-esteem (MSWS) were conducted. The results of this study revealed a decrease in QoL and reduced body-related self-esteem in anosmic patients. Furthermore, QoL and self-esteem were correlated with depressive symptoms. As self-esteem, QoL and depressive symptoms in anosmia interact with each other, we suggest that self-esteem should be considered in the medical history, in order to provide a personalised intervention, adapted to the patient's needs. © 2017 The Authors. Clinical Otolaryngology Published by John Wiley & Sons Ltd.

Development of an International Odor Identification Test for Children: The Universal Sniff Test.

PubMed

Schriever, Valentin A; Agosin, Eduardo; Altundag, Aytug; Avni, Hadas; Cao Van, Helene; Cornejo, Carlos; de Los Santos, Gonzalo; Fishman, Gad; Fragola, Claudio; Guarneros, Marco; Gupta, Neelima; Hudson, Robyn; Kamel, Reda; Knaapila, Antti; Konstantinidis, Iordanis; Landis, Basile N; Larsson, Maria; Lundström, Johan N; Macchi, Alberto; Mariño-Sánchez, Franklin; Martinec Nováková, Lenka; Mori, Eri; Mullol, Joaquim; Nord, Marie; Parma, Valentina; Philpott, Carl; Propst, Evan J; Rawan, Ahmed; Sandell, Mari; Sorokowska, Agnieszka; Sorokowski, Piotr; Sparing-Paschke, Lisa-Marie; Stetzler, Carolin; Valder, Claudia; Vodicka, Jan; Hummel, Thomas

2018-07-01

To assess olfactory function in children and to create and validate an odor identification test to diagnose olfactory dysfunction in children, which we called the Universal Sniff (U-Sniff) test. This is a multicenter study involving 19 countries. The U-Sniff test was developed in 3 phases including 1760 children age 5-7 years. Phase 1: identification of potentially recognizable odors; phase 2: selection of odorants for the odor identification test; and phase 3: evaluation of the test and acquisition of normative data. Test-retest reliability was evaluated in a subgroup of children (n = 27), and the test was validated using children with congenital anosmia (n = 14). Twelve odors were familiar to children and, therefore, included in the U-Sniff test. Children scored a mean ± SD of 9.88 ± 1.80 points out of 12. Normative data was obtained and reported for each country. The U-Sniff test demonstrated a high test-retest reliability (r 27  = 0.83, P < .001) and enabled discrimination between normosmia and children with congenital anosmia with a sensitivity of 100% and specificity of 86%. The U-Sniff is a valid and reliable method of testing olfaction in children and can be used internationally. Copyright © 2018 Elsevier Inc. All rights reserved.

Subclinical dopaminergic dysfunction in asymptomatic Parkinson's disease patients' relatives with a decreased sense of smell.

PubMed

Berendse, H W; Booij, J; Francot, C M; Bergmans, P L; Hijman, R; Stoof, J C; Wolters, E C

2001-07-01

By the time a clinical diagnosis of Parkinson's disease (PD) is made, a significant loss of dopaminergic neurons has already occurred. Identifying patients in the period between the presumed onset of dopaminergic cell loss and the appearance of clinical parkinsonism may be of major importance in the development of effective neuroprotective treatment strategies. In an effort to develop a feasible strategy to detect preclinical PD, a combination of olfactory processing tasks, including odor detection, odor identification, and odor discrimination was used to select groups of hyposmic and normosmic individuals from a total of 250 relatives (parents, siblings, or children) of subjects with PD. Single photon emission computed tomography (SPECT) with [123I]beta-CIT as a dopamine transporter ligand was used to assess nigrostriatal dopaminergic function in 25 hyposmic and 23 normosmic relatives of PD patients. An abnormal reduction in striatal dopamine transporter binding was found in 4 out of 25 hyposmic relatives of PD patients, two of whom subsequently developed clinical parkinsonism, and in none of the 23 normosmic relatives. These observations demonstrate that subclinical reductions in dopamine transporter binding can be detected in asymptomatic relatives of sporadic PD patients by means of [123I]beta-CIT and SPECT. The results further indicate that olfactory deficits may precede clinical motor signs in PD.

Wiring Olfaction: The Cellular and Molecular Mechanisms that Guide the Development of Synaptic Connections from the Nose to the Cortex

PubMed Central

de Castro, Fernando

2009-01-01

Within the central nervous system, the olfactory system fascinates by its developmental and physiological particularities, and is one of the most studied models to understand the mechanisms underlying the guidance of growing axons to their appropriate targets. A constellation of contact-mediated (laminins, CAMs, ephrins, etc.) and secreted mechanisms (semaphorins, slits, growth factors, etc.) are known to play different roles in the establishment of synaptic interactions between the olfactory epithelium, olfactory bulb (OB) and olfactory cortex. Specific mechanisms of this system (including the amazing family of about 1000 different olfactory receptors) have been also proposed. In the last years, different reviews have focused in partial sights, specially in the mechanisms involved in the formation of the olfactory nerve, but a detailed review of the mechanisms implicated in the development of the connections among the different olfactory structures (olfactory epithelium, OB, olfactory cortex) remains to be written. In the present work, we afford this systematic review: the different cellular and molecular mechanisms which rule the formation of the olfactory nerve, the lateral olfactory tract and the intracortical connections, as well as the few data available regarding the accessory olfactory system. These mechanisms are compared, and the implications of the differences and similarities discussed in this fundamental scenario of ontogeny. PMID:20582279

Functional Reintegration of Sensory Neurons and Transitional Dendritic Reduction of Mitral/Tufted Cells during Injury-Induced Recovery of the Larval Xenopus Olfactory Circuit.

PubMed

Hawkins, Sara J; Weiss, Lukas; Offner, Thomas; Dittrich, Katarina; Hassenklöver, Thomas; Manzini, Ivan

2017-01-01

Understanding the mechanisms involved in maintaining lifelong neurogenesis has a clear biological and clinical interest. In the present study, we performed olfactory nerve transection on larval Xenopus to induce severe damage to the olfactory circuitry. We surveyed the timing of the degeneration, subsequent rewiring and functional regeneration of the olfactory system following injury. A range of structural labeling techniques and functional calcium imaging were performed on both tissue slices and whole brain preparations. Cell death of olfactory receptor neurons and proliferation of stem cells in the olfactory epithelium were immediately increased following lesion. New olfactory receptor neurons repopulated the olfactory epithelium and once again showed functional responses to natural odorants within 1 week after transection. Reinnervation of the olfactory bulb (OB) by newly formed olfactory receptor neuron axons also began at this time. Additionally, we observed a temporary increase in cell death in the OB and a subsequent loss in OB volume. Mitral/tufted cells, the second order neurons of the olfactory system, largely survived, but transiently lost dendritic tuft complexity. The first odorant-induced responses in the OB were observed 3 weeks after nerve transection and the olfactory network showed signs of major recovery, both structurally and functionally, after 7 weeks.

Functional Reintegration of Sensory Neurons and Transitional Dendritic Reduction of Mitral/Tufted Cells during Injury-Induced Recovery of the Larval Xenopus Olfactory Circuit

PubMed Central

Hawkins, Sara J.; Weiss, Lukas; Offner, Thomas; Dittrich, Katarina; Hassenklöver, Thomas; Manzini, Ivan

2017-01-01

Understanding the mechanisms involved in maintaining lifelong neurogenesis has a clear biological and clinical interest. In the present study, we performed olfactory nerve transection on larval Xenopus to induce severe damage to the olfactory circuitry. We surveyed the timing of the degeneration, subsequent rewiring and functional regeneration of the olfactory system following injury. A range of structural labeling techniques and functional calcium imaging were performed on both tissue slices and whole brain preparations. Cell death of olfactory receptor neurons and proliferation of stem cells in the olfactory epithelium were immediately increased following lesion. New olfactory receptor neurons repopulated the olfactory epithelium and once again showed functional responses to natural odorants within 1 week after transection. Reinnervation of the olfactory bulb (OB) by newly formed olfactory receptor neuron axons also began at this time. Additionally, we observed a temporary increase in cell death in the OB and a subsequent loss in OB volume. Mitral/tufted cells, the second order neurons of the olfactory system, largely survived, but transiently lost dendritic tuft complexity. The first odorant-induced responses in the OB were observed 3 weeks after nerve transection and the olfactory network showed signs of major recovery, both structurally and functionally, after 7 weeks. PMID:29234276

Extrabulbar olfactory system and nervus terminalis FMRFamide immunoreactive components in Xenopus laevis ontogenesis.

PubMed

Pinelli, Claudia; D'Aniello, Biagio; Polese, Gianluca; Rastogi, Rakesh K

2004-09-01

The extrabulbar olfactory system (EBOS) is a collection of nerve fibers which originate from primary olfactory receptor-like neurons and penetrate into the brain bypassing the olfactory bulbs. Our description is based upon the application of two neuronal tracers (biocytin, carbocyanine DiI) in the olfactory sac, at the cut end of the olfactory nerve and in the telencephalon of the developing clawed frog. The extrabulbar olfactory system was observed already at stage 45, which is the first developmental stage compatible with our techniques; at this stage, the extrabulbar olfactory system fibers terminated diffusely in the preoptic area. A little later in development, i.e. at stage 50, the extrabulbar olfactory system was maximally developed, extending as far caudally as the rhombencephalon. In the metamorphosing specimens, the extrabulbar olfactory system appeared reduced in extension; caudally, the fiber terminals did not extend beyond the diencephalon. While a substantial overlapping of biocytin/FMRFamide immunoreactivity was observed along the olfactory pathways as well as in the telencephalon, FMRFamide immunoreactivity was never observed to be colocalized in the same cellular or fiber components visualized by tracer molecules. The question whether the extrabulbar olfactory system and the nervus terminalis (NT) are separate anatomical entities or represent an integrated system is discussed.

Localization of α1-2 Fucose Glycan in the Mouse Olfactory Pathway.

PubMed

Kondoh, Daisuke; Kamikawa, Akihiro; Sasaki, Motoki; Kitamura, Nobuo

2017-01-01

Glycoconjugates in the olfactory system play critical roles in neuronal formation, and α1-2 fucose (α1-2Fuc) glycan mediates neurite outgrowth and synaptic plasticity. Histochemical findings of α1-2Fuc glycan in the mouse olfactory system detected using Ulex europaeus agglutinin-I (UEA-I) vary. This study histochemically assessed the main olfactory and vomeronasal pathways in male and female ICR and C57BL/6J mice aged 3-4 months using UEA-I. Ulex europaeus agglutinin-I reacted with most receptor cells arranged mainly at the basal region of the olfactory epithelium. The olfactory nerve layer and glomerular layer of the main olfactory bulb were speckled with positive UEA-I staining, and positive fibers were scattered from the glomerular to the internal plexiform layer. The lateral olfactory tract and rostral migratory stream were also positive for UEA-I. We identified superficial short-axon cells, interneurons of the external plexiform layer, external, middle and internal tufted cells, mitral cells and granule cells as the origins of the UEA-I-positive fibers in the main olfactory bulb. The anterior olfactory nucleus, anterior piriform cortex and olfactory tubercle were negative for UEA-I. Most receptor cells in the vomeronasal epithelium and most glomeruli of the accessory olfactory bulb were positive for UEA-I. Our findings indicated that α1-2Fuc glycan is located within the primary and secondary, but not the ternary, pathways of the main olfactory system, in local circuits of the main olfactory bulb and within the primary, but not secondary, pathway of the vomeronasal system. © 2016 S. Karger AG, Basel.

[Clinical observation of isolated congenital anosmia].

PubMed

Li, Li; Wei, Yong-xiang; Wang, Ning-yu; Miao, Xu-tao; Yang, Ling; Ge, Xiao-hui; Wu, Ying; Liu, Jia; Tian, Jun; Li, Kun-yan; Liu, Chun-li

2013-12-01

To introduce 8 patients with isolated congenital anosmia and to discuss the clinical manifestations, imaging characteristics and family characteristics of this rarely seen disorder. Eight patients with isolated congenital anosmia treated between April 2007 and April 2012 were reviewed retrospectively. There were 4 males and 4 females. A detailed medical history collection, physical examination, nasal endoscopy, T&T and Sniffin'Sticks subjective olfactory function tests, olfactory event-related potentials sinonasal computed tomography scan and sex hormones level monitoring were performed in all patients. Seven cases underwent magnetic resonance image of olfactory pathway examination. All patients were anosmia without evidence of other defects. ENT physical examination, nasal endoscopy and computed tomography scan were normal except 4 cases with obvious nasal septum deviation, 2 cases with concha bullosa. Subjective olfactory test indicated all of them were anosmia. Olfactory event-related potentials were obtained in only 1 patient. Magnetic resonance imaging revealed the smaller or atrophy olfactory bulb and olfactory tract in five cases, the absence of olfactory bulbs and tracts in two case. A female patient did not have MRI examination because of wearing IUDs. Detection of 8 patients of sex hormones were normal. Family characteristics: 3 patients showed family inheritance pattern. The diagnosis of isolated congenital anosmia should be based on chief complaint, medical history, physical examination, olfactory test, nasal endoscopy, olfactory testing, olfactory imaging and olfactory event-related potentials. Magnetic resonance image of olfactory pathway and olfactory event-related potentials have important value for the diagnosis. More attention should be paid to the genetic susceptibility of the family.

Uptake and transport of manganese in primary and secondary olfactory neurones in pike.

PubMed

Tjälve, H; Mejàre, C; Borg-Neczak, K

1995-07-01

gamma-spectrometry and autoradiography were used to examine the axoplasmic flow of manganese in the olfactory nerves and to study the uptake of the metal in the brain after application of 54Mn2+ in the olfactory chambers of pikes. The results show that the 54Mn2+ is taken up in the olfactory receptor cells and is transported at a constant rate along the primary olfactory neurones into the brain. The maximal velocity for the transported 54Mn2+ was 2.90 +/- 0.21 mm/hr (mean +/- S.E.) at 10 degrees, which was the temperature used in the experiments. The 54Mn2+ accumulated in the entire olfactory bulbs, although most marked in central and caudal parts. The metal was also seen to migrate into large areas of the telencephalon, apparently mainly via the secondary olfactory axons present in the medial olfactory tract. A transfer along fibres of the medial olfactory tract probably also explains the labelling which was seen in the diencephalon down to the hypothalamus. The results also showed that there is a pathway connecting the two olfactory bulbs of the pike and that this can carry the metal. Our data further showed a marked accumulation of 54Mn2+ in the meningeal epithelium and in the contents of the meningeal sacs surrounding the olfactory bulbs. It appears from our study that manganese has the ability to pass the synaptic junctions between the primary and the secondary olfactory neurones in the olfactory bulbs and to migrate along secondary olfactory pathways into the telencephalon and the diencephalon.(ABSTRACT TRUNCATED AT 250 WORDS)

No evidence for visual context-dependency of olfactory learning in Drosophila

NASA Astrophysics Data System (ADS)

Yarali, Ayse; Mayerle, Moritz; Nawroth, Christian; Gerber, Bertram

2008-08-01

How is behaviour organised across sensory modalities? Specifically, we ask concerning the fruit fly Drosophila melanogaster how visual context affects olfactory learning and recall and whether information about visual context is getting integrated into olfactory memory. We find that changing visual context between training and test does not deteriorate olfactory memory scores, suggesting that these olfactory memories can drive behaviour despite a mismatch of visual context between training and test. Rather, both the establishment and the recall of olfactory memory are generally facilitated by light. In a follow-up experiment, we find no evidence for learning about combinations of odours and visual context as predictors for reinforcement even after explicit training in a so-called biconditional discrimination task. Thus, a ‘true’ interaction between visual and olfactory modalities is not evident; instead, light seems to influence olfactory learning and recall unspecifically, for example by altering motor activity, alertness or olfactory acuity.

Individual olfactory perception reveals meaningful nonolfactory genetic information

PubMed Central

Secundo, Lavi; Snitz, Kobi; Weissler, Kineret; Pinchover, Liron; Shoenfeld, Yehuda; Loewenthal, Ron; Agmon-Levin, Nancy; Frumin, Idan; Bar-Zvi, Dana; Shushan, Sagit; Sobel, Noam

2015-01-01

Each person expresses a potentially unique subset of ∼400 different olfactory receptor subtypes. Given that the receptors we express partially determine the odors we smell, it follows that each person may have a unique nose; to capture this, we devised a sensitive test of olfactory perception we termed the “olfactory fingerprint.” Olfactory fingerprints relied on matrices of perceived odorant similarity derived from descriptors applied to the odorants. We initially fingerprinted 89 individuals using 28 odors and 54 descriptors. We found that each person had a unique olfactory fingerprint (P < 10−10), which was odor specific but descriptor independent. We could identify individuals from this pool using randomly selected sets of 7 odors and 11 descriptors alone. Extrapolating from this data, we determined that using 34 odors and 35 descriptors we could individually identify each of the 7 billion people on earth. Olfactory perception, however, fluctuates over time, calling into question our proposed perceptual readout of presumably stable genetic makeup. To test whether fingerprints remain informative despite this temporal fluctuation, building on the linkage between olfactory receptors and HLA, we hypothesized that olfactory perception may relate to HLA. We obtained olfactory fingerprints and HLA typing for 130 individuals, and found that olfactory fingerprint matching using only four odorants was significantly related to HLA matching (P < 10−4), such that olfactory fingerprints can save 32% of HLA tests in a population screen (P < 10−6). In conclusion, a precise measure of olfactory perception reveals meaningful nonolfactory genetic information. PMID:26100865

A Subtype-Specific Critical Period for Neurogenesis in the Postnatal Development of Mouse Olfactory Glomeruli

PubMed Central

Ito, Keishi; Arakawa, Sousuke; Murakami, Shingo; Sawamoto, Kazunobu

2012-01-01

Sensory input is essential for the normal development of sensory centers in the brain, such as the somatosensory, visual, auditory, and olfactory systems. Visual deprivation during a specific developmental stage, called the critical period, results in severe and irreversible functional impairments in the primary visual cortex. Olfactory deprivation in the early postnatal period also causes significant developmental defects in the olfactory bulb, the primary center for olfaction. Olfactory bulb interneurons are continuously generated from neural stem cells in the ventricular-subventricular zone, suggesting that the olfactory system has plasticity even in adulthood. Here, we investigated the effect of transient neonatal olfactory deprivation on the addition of interneurons to the glomerular layer of the adult mouse olfactory bulb. We found that the addition of one subtype of interneurons was persistently inhibited even after reopening the naris. BrdU pulse-chase experiments revealed that the neonatal olfactory deprivation predominantly affected an early phase in the maturation of this neuronal subtype in the olfactory bulb. Subjecting the mice to odor stimulation for 6 weeks after naris reopening resulted in significant recovery from the histological and functional defects caused by the olfactory deprivation. These results suggest that a subtype-specific critical period exists for olfactory bulb neurogenesis, but that this period is less strict and more plastic compared with the critical periods for other systems. This study provides new insights into the mechanisms of postnatal neurogenesis and a biological basis for the therapeutic effect of olfactory training. PMID:23133633

[Clinical and MRI Findings in Patients with Congenital Anosmia].

PubMed

Ogawa, Takao; Kato, Tomohisa; Ono, Mayu; Shimizu, Takeshi

2015-08-01

The clinical characteristics of 16 patients with congenital anosmia were examined retrospectively. MRI (magnetic resonance imaging) was used to assess the morphological changes in the olfactory bulbs and olfactory sulci according to the method of P. Rombaux (2009). Congenital anosmia was divided into two forms: syndromic forms in association with a syndrome, and isolated forms without evidence of other defects. Only three patients (19%) in our series had syndromic forms of congenital anosmia, such as the Kallmann syndrome. Most cases (13 patients, 81%) had isolated congenital anosmia. Psychophysical testing of the olfactory function included T&T olfactometry and the intravenous Alinamin test, which are widely used in Japan. In T&T olfactometry, detection and recognition thresholds for the five odorants are used to assign a diagnostic category representing the level of olfactory function. Most cases (14 patients, 88%) showed off-scale results on T&T olfactometry, and the Alinamin test resulted in no response in all 11 patients who underwent the test. Abnormal MRI findings of the olfactory bulbs and sulci were detected in 15 of 16 patients (94%). Olfactory bulbs were bilaterally absent in nine patients (56%), and two patients (13%) had unilateral olfactory bulbs. Four patients (25%) had bilateral hypoplastic olfactory bulbs, and only one patient had normal olfactory bulbs (6%). The olfactory sulcus was unilaterally absent in one patient (6%), and nine patients (56%) had bilaterally hypoplastic olfactory sulci. Two patients (13%) had a unilateral normal olfactory sulcus and hypoplastic olfactory sulcus. Three patients (19%) had normal olfactory sulci. Quantitative analysis showed that the volume of olfactory bulbs varied from 0 mm3 to 63.5 mm3, with a mean volume of 10.20 ± 18 mm3, and the mean depth of the olfactory sulcus varied from 0 mm to 12.22 mm, with a mean length of 4.85 ± 4.1 mm. Currently, there is no effective treatment for congenital anosmia. However, diagnosis of congenital anosmia is important, as its presence can lead to dangerous situations. Careful examination for hypogonadism is also required in people with anosmia. MRI examinations of the olfactory bulbs and sulci were useful for the diagnosis of congenital anosmia.

REM sleep Behaviour Disorder.

PubMed

Ferini-Strambi, Luigi; Rinaldi, Fabrizio; Giora, Enrico; Marelli, Sara; Galbiati, Andrea

2016-01-01

Rapid Eye Movement (REM) sleep Behaviour Disorder (RBD) is a REM sleep parasomnia characterized by loss of the muscle atonia that typically occurs during REM sleep, therefore allowing patients to act out their dreams. RBD manifests itself clinically as a violent behaviour occurring during the night, and is detected at the polysomnography by phasic and/or tonic muscle activity on the electromyography channel. In absence of neurological signs or central nervous system lesions, RBD is defined as idiopathic. Nevertheless, in a large number of cases the development of neurodegenerative diseases in RBD patients has been described, with the duration of the follow-up representing a fundamental aspect. A growing number of clinical, neurophysiologic and neuropsychological studies aimed to detect early markers of neurodegenerative dysfunction in RBD patients. Anyway, the evidence of impaired cortical activity, subtle neurocognitive dysfunction, olfactory and autonomic impairment and neuroimaging brain changes in RBD patients is challenging the concept of an idiopathic form of RBD, supporting the idea of RBD as an early manifestation of a more complex neurodegenerative process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Contribution of DA Signaling to Appetitive Odor Perception in a Drosophila Model.

PubMed

Pu, Yuhan; Palombo, Melissa Megan Masserant; Shen, Ping

2018-04-13

Understanding cognitive processes that translate chemically diverse olfactory stimuli to specific appetitive drives remains challenging. We have shown that food-related odors arouse impulsive-like feeding of food media that are palatable and readily accessible in well-nourished Drosophila larvae. Here we provide evidence that two assemblies of four dopamine (DA) neurons, one per brain hemisphere, contribute to perceptual processing of the qualitative and quantitative attributes of food scents. These DA neurons receive neural representations of chemically diverse food-related odors, and their combined neuronal activities become increasingly important as the chemical complexity of an appetizing odor stimulus increases. Furthermore, in each assembly of DA neurons, integrated odor signals are transformed to one-dimensional DA outputs that have no intrinsic reward values. Finally, a genetic analysis has revealed a D1-type DA receptor (Dop1R1)-gated mechanism in neuropeptide Y-like neurons that assigns appetitive significance to selected DA outputs. Our findings suggest that fly larvae provide a useful platform for elucidation of molecular and circuit mechanisms underlying cognitive processing of olfactory and possibly other sensory cues.

Perceptions of erectile dysfunction and phosphodiesterase type 5 inhibitor therapy in a qualitative study of men and women in affected relationships.

PubMed

McGraw, Sarah A; Rosen, Raymond C; Althof, Stanley E; Dunn, Marian; Cameron, Ann; Wong, David

2015-01-01

Erectile dysfunction negatively affects men and women in relationships; however, the subjective experience of erectile dysfunction and phosphodiesterase-type 5 inhibitor therapy remains poorly understood. The authors therefore characterized participants' subjective understanding of erectile dysfunction and phosphodiesterase-type 5 inhibitor therapy using individual interviews with affected heterosexual men (n = 58) and women (n = 65). Responses were characterized by 6 psychosocial domains: explanation of the experience, emotional responses, socially expected responses, value of sex, communication with the partner, and treatment expectations. The findings may aid clinicians in relating to men with erectile dysfunction and thus potentially improve effectiveness of therapy.

Neuronal nitric oxide synthase in the olfactory system of an adult teleost fish Oreochromis mossambicus.

PubMed

Singru, Praful S; Sakharkar, Amul J; Subhedar, Nishikant

2003-07-11

The aim of the present study is to explore the distribution of nitric oxide synthase in the olfactory system of an adult teleost, Oreochromis mossambicus using neuronal nitric oxide synthase (nNOS) immunocytochemistry and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry methods. Intense nNOS immunoreactivity was noticed in several olfactory receptor neurons (ORNs), in their axonal extensions over the olfactory nerve and in some basal cells of the olfactory epithelium. nNOS containing fascicles of the ORNs enter the bulb from its rostral pole, spread in the olfactory nerve layer in the periphery of the bulb and display massive innervation of the olfactory glomeruli. Unilateral ablation of the olfactory organ resulted in dramatic loss of nNOS immunoreactivity in the olfactory nerve layer of the ipsilateral bulb. In the olfactory bulb of intact fish, some granule cells showed intense immunoreactivity; dendrites arising from the granule cells could be traced to the glomerular layer. Of particular interest is the occurrence of nNOS immunoreactivity in the ganglion cells of the nervus terminalis. nNOS containing fibers were also encountered in the medial olfactory tracts as they extend to the telencephalon. The NADPHd staining generally coincides with that of nNOS suggesting that it may serve as a marker for nNOS in the olfactory system of this fish. However, mismatch was encountered in the case of mitral cells, while all are nNOS-negative, few were NADPHd positive. The present study for the first time revealed the occurrence of nNOS immunoreactivity in the ORNs of an adult vertebrate and suggests a role for nitric oxide in the transduction of odor stimuli, regeneration of olfactory epithelium and processing of olfactory signals.

Olfactory epithelium influences the orientation of mitral cell dendrites during development.

PubMed

López-Mascaraque, Laura; García, Concepción; Blanchart, Albert; De Carlos, Juan A

2005-02-01

We have established previously that, although the olfactory epithelium is absent in the homozygous Pax-6 mutant mouse, an olfactory bulb-like structure (OBLS) does develop. Moreover, this OBLS contains cells that correspond to mitral cells, the primary projection neurons in the olfactory bulb. The current study aimed to address whether the dendrites of mitral cells in the olfactory bulb or in the OBLS mitral-like cells, exhibit a change in orientation in the presence of the olfactory epithelium. The underlying hypothesis is that the olfactory epithelium imparts a trophic signal on mitral and mitral-like cell that influences the growth of their primary dendrites, orientating them toward the surface of the olfactory bulb. Hence, we cultured hemibrains from wild-type and Pax 6 mutant mice from two different embryonic stages (embryonic days 14 and 15) either alone or in coculture with normal olfactory epithelial explants or control tissue (cerebellum). Our results indicate that the final dendritic orientation of mitral and mitral-like cells is directly influenced both by age and indeed by the presence of the olfactory epithelium. Copyright 2004 Wiley-Liss, Inc.

Smell or vision? The use of different sensory modalities in predator discrimination.

PubMed

Fischer, Stefan; Oberhummer, Evelyne; Cunha-Saraiva, Filipa; Gerber, Nina; Taborsky, Barbara

2017-01-01

Theory predicts that animals should adjust their escape responses to the perceived predation risk. The information animals obtain about potential predation risk may differ qualitatively depending on the sensory modality by which a cue is perceived. For instance, olfactory cues may reveal better information about the presence or absence of threats, whereas visual information can reliably transmit the position and potential attack distance of a predator. While this suggests a differential use of information perceived through the two sensory channels, the relative importance of visual vs. olfactory cues when distinguishing between different predation threats is still poorly understood. Therefore, we exposed individuals of the cooperatively breeding cichlid Neolamprologus pulcher to a standardized threat stimulus combined with either predator or non-predator cues presented either visually or chemically. We predicted that flight responses towards a threat stimulus are more pronounced if cues of dangerous rather than harmless heterospecifics are presented and that N. pulcher , being an aquatic species, relies more on olfaction when discriminating between dangerous and harmless heterospecifics. N. pulcher responded faster to the threat stimulus, reached a refuge faster and entered a refuge more likely when predator cues were perceived. Unexpectedly, the sensory modality used to perceive the cues did not affect the escape response or the duration of the recovery phase. This suggests that N. pulcher are able to discriminate heterospecific cues with similar acuity when using vision or olfaction. We discuss that this ability may be advantageous in aquatic environments where the visibility conditions strongly vary over time. The ability to rapidly discriminate between dangerous predators and harmless heterospecifics is crucial for the survival of prey animals. In seasonally fluctuating environment, sensory conditions may change over the year and may make the use of multiple sensory modalities for heterospecific discrimination highly beneficial. Here we compared the efficacy of visual and olfactory senses in the discrimination ability of the cooperatively breeding cichlid Neolamprologus pulcher . We presented individual fish with visual or olfactory cues of predators or harmless heterospecifics and recorded their flight response. When exposed to predator cues, individuals responded faster, reached a refuge faster and were more likely to enter the refuge. Unexpectedly, the olfactory and visual senses seemed to be equally efficient in this discrimination task, suggesting that seasonal variation of water conditions experienced by N. pulcher may necessitate the use of multiple sensory channels for the same task.

Cognitive Impairment and Structural Abnormalities in Late Life Depression with Olfactory Identification Impairment: an Alzheimer's Disease-Like Pattern.

PubMed

Chen, Ben; Zhong, Xiaomei; Mai, Naikeng; Peng, Qi; Wu, Zhangying; Ouyang, Cong; Zhang, Weiru; Liang, Wanyuan; Wu, Yujie; Liu, Sha; Chen, Lijian; Ning, Yuping

2018-03-15

Late-life depression patients are at a high risk of developing Alzheimer's disease, and diminished olfactory identification is an indicator in early screening for Alzheimer's disease in the elderly. However, whether diminished olfactory identification is associated with risk of developing Alzheimer's disease in late-life depression patients remains unclear. One hundred and twenty-five late-life depression patients, 50 Alzheimer's disease patients, and 60 normal controls were continuously recruited. The participants underwent a clinical evaluation, olfactory test, neuropsychological assessment, and neuroimaging assessment. The olfactory identification impairment in late-life depression patients was milder than that in Alzheimer's disease patients. Diminished olfactory identification was significantly correlated with worse cognitive performance (global function, memory language, executive function, and attention) and reduced grey matter volume (olfactory bulb and hippocampus) in the late-life depression patients. According to a multiple linear regression analysis, olfactory identification was significantly associated with the memory scores in late-life depression group (B=1.623, P<.001). The late-life depression with olfactory identification impairment group had worse cognitive performance (global, memory, language, and executive function) and more structural abnormalities in Alzheimer's disease-related regions than the late-life depression without olfactory identification impairment group, and global cognitive function and logical memory in the late-life depression without olfactory identification impairment group was intact. Reduced volume observed in many areas (hippocampus, precuneus, etc.) in the Alzheimer's disease group was also observed in late-life depression with olfactory identification impairment group but not in the late-life depression without olfactory identification impairment group. The patterns of cognitive impairment and structural abnormalities in late-life depression with olfactory identification impairment patients were similar to those in Alzheimer's disease; olfactory identification may help identify late-life depression patients who are at a high risk of developing Alzheimer's disease.

Fluctuating olfactory sensitivity and distorted odor perception in allergic rhinitis.

PubMed

Apter, A J; Gent, J F; Frank, M E

1999-09-01

To characterize the relationship between allergic rhinitis, the severity and duration of nasal disease, olfactory function, and self-reported olfactory symptoms, including fluctuations or distortions in odor perception. Assessment of olfactory function and symptoms of 90 patients with allergic rhinitis. A clinic of a university teaching hospital and research facility. Sixty patients who presented to the Taste and Smell Clinic who had positive allergy test results and 30 patients who presented to the Allergy-Immunology Clinic. The Taste and Smell Clinic patients were grouped by nasal-sinus disease status (30 without chronic rhinosinusitis or nasal polyps, 14 with chronic rhinosinusitis but without polyps, and 16 with nasal polyps). Subjective olfactory symptom questionnaire and objective olfactory function tests. The Allergy-Immunology Clinic patients were diagnosed as being normosmic and the Taste and Smell Clinic patients as being hyposmic or anosmic with olfactory loss that increased significantly with nasal-sinus disease severity. Comparisons with normative data confirm that olfactory scores observed in all groups were significantly lower than expected because of the aging process alone. The self-reported duration of olfactory loss increased significantly with nasal-sinus disease severity. The Taste and Smell Clinic patients without chronic rhinosinusitis or nasal polyps reported the greatest incidence of olfactory distortions and olfactory loss associated with upper respiratory tract infections. There appears to be a continuum of duration and severity of olfactory loss in allergic rhinitis that parallels increasing severity of nasal-sinus disease. As a result of the increased frequency of respiratory infection associated with allergic rhinitis, these patients are at risk for damage to the olfactory epithelium.

Chemosensory interaction: acquired olfactory impairment is associated with decreased taste function.

PubMed

Landis, Basile N; Scheibe, Mandy; Weber, Cornelia; Berger, Robert; Brämerson, Annika; Bende, Mats; Nordin, Steven; Hummel, Thomas

2010-08-01

Olfaction, taste and trigeminal function are three distinct modalities. However, in daily life they are often activated concomitantly. In health and disease, it has been shown that in two of these senses, the trigeminal and olfactory senses, modification of one sense leads to changes in the other sense and vice versa. The objective of the study was to investigate whether and (if so) how, the third modality, taste, is influenced by olfactory impairment. We tested 210 subjects with normal (n = 107) or impaired (n = 103) olfactory function for their taste identification capacities. Validated tests were used for olfactory and gustatory testing (Sniffin' Sticks, Taste Strips). In an additional experiment, healthy volunteers underwent reversible olfactory cleft obstruction to investigate short-time changes of gustatory function after olfactory alteration. Mean gustatory identification (taste strip score) for the subjects with impaired olfaction was 19.4 +/- 0.6 points and 22.9 +/- 0.5 points for those with normal olfactory function (t = 4.6, p < 0.001). The frequencies of both, smell and taste impairments interacted significantly (Chi(2), F = 16.4, p < 0.001), and olfactory and gustatory function correlated (r (210) = 0.30, p < 0.001). Neither age nor olfactory impairment cause effects interfered with this olfactory-gustatory interaction. In contrast, after short-lasting induced olfactory decrease, gustatory function remained unchanged. The present study suggests that longstanding impaired olfactory function is associated with decreased gustatory function. These findings seem to extend previously described mutual chemosensory interactions also to smell and taste. It further raises the question whether chemical senses in general decrease mutually after acquired damage.

Role of Nrf2 antioxidant defense in mitigating cadmium-induced oxidative stress in the olfactory system of zebrafish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Lu; Gallagher, Evan P., E-mail: evang3@uw.edu

2013-01-15

Exposure to trace metals can disrupt olfactory function in fish leading to a loss of behaviors critical to survival. Cadmium (Cd) is an olfactory toxicant that elicits cellular oxidative stress as a mechanism of toxicity while also inducing protective cellular antioxidant genes via activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. However, the molecular mechanisms of Cd-induced olfactory injury have not been characterized. In the present study, we investigated the role of the Nrf2-mediated antioxidant defense pathway in protecting against Cd-induced olfactory injury in zebrafish. A dose-dependent induction of Nrf2-regulated antioxidant genes associated with cellular responses to oxidativemore » stress was observed in the olfactory system of adult zebrafish following 24 h Cd exposure. Zebrafish larvae exposed to Cd for 3 h showed increased glutathione S-transferase pi (gst pi), glutamate–cysteine ligase catalytic subunit (gclc), heme oxygenase 1 (hmox1) and peroxiredoxin 1 (prdx1) mRNA levels indicative of Nrf2 activation, and which were blocked by morpholino-mediated Nrf2 knockdown. The inhibition of antioxidant gene induction in Cd-exposed Nrf2 morphants was associated with disruption of olfactory driven behaviors, increased cell death and loss of olfactory sensory neurons (OSNs). Nrf2 morphants also exhibited a downregulation of OSN-specific genes after Cd exposure. Pre-incubation of embryos with sulforaphane (SFN) partially protected against Cd-induced olfactory tissue damage. Collectively, our results indicate that oxidative stress is an important mechanism of Cd-mediated injury in the zebrafish olfactory system. Moreover, the Nrf2 pathway plays a protective role against cellular oxidative damage and is important in maintaining zebrafish olfactory function. -- Highlights: ► Oxidative stress is an important mechanism of Cd-mediated olfactory injury. ► Cd induces antioxidant gene expression in the zebrafish olfactory system. ► The olfactory antioxidant response is blocked by Nrf2 knockdown. ► Disruption of olfactory neurobehaviors is associated with Nrf2 knockdown. ► Nrf2 morphants show increased cell death and olfactory sensory neuron loss.« less

The Embryonic Septum and Ventral Pallium, New Sources of Olfactory Cortex Cells

PubMed Central

de Carlos, Juan A.

2012-01-01

The mammalian olfactory cortex is a complex structure located along the rostro-caudal extension of the ventrolateral prosencephalon, which is divided into several anatomically and functionally distinct areas: the anterior olfactory nucleus, piriform cortex, olfactory tubercle, amygdaloid olfactory nuclei, and the more caudal entorhinal cortex. Multiple forebrain progenitor domains contribute to the cellular diversity of the olfactory cortex, which is invaded simultaneously by cells originating in distinct germinal areas in the dorsal and ventral forebrain. Using a combination of dye labeling techniques, we identified two novel areas that contribute cells to the developing olfactory cortices, the septum and the ventral pallium, from which cells migrate along a radial and then a tangential path. We characterized these cell populations by comparing their expression of calretinin, calbindin, reelin and Tbr1 with that of other olfactory cell populations. PMID:22984546

Chemosensory Dysfunction in Alcohol-Related Disorders: A Joint Exploration of Olfaction and Taste.

PubMed

Brion, Mélanie; de Timary, Philippe; Vander Stappen, Caroline; Guettat, Lamia; Lecomte, Benoît; Rombaux, Philippe; Maurage, Pierre

2015-11-01

Chemosensory (olfaction-taste) dysfunctions are considered as reliable biomarkers in many neurological and psychiatric states. However, experimental measures of chemosensory abilities are lacking in alcohol-dependence (AD) and Korsakoff Syndrome (KS, a neurological complication of AD), despite the role played by alcohol-related odors and taste in the emergence and maintenance of AD. This study thus investigated chemosensory impairments in AD and KS. Olfactory-gustatory measures were taken among 20 KS, 20 AD, and 20 control participants. Olfaction (odor detection-discrimination-identification) was assessed using the "Sniffin Sticks" battery and taste was measured using the "Taste Strips" task. Impairments were found for high-level olfaction in AD (odor discrimination) and KS (odor discrimination-identification), even after controlling for psychopathological comorbidities. Gustatory deficits were also observed in both groups, indexing a global deficit for chemosensory perception. Finally, the gradient of impairment between the successive disease stages for odor identification suggests that the hypothesis of a continuum between AD and KS regarding cognitive deficits can be generalized to chemosensory perception. AD and KS are thus characterized by deficits in chemosensory abilities, which could constitute a marker of the AD-KS transition. In view of its deleterious influence on everyday life, chemosensory dysfunction should also be taken into account in clinical settings. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Olfactory memory in the old and very old: relations to episodic and semantic memory and APOE genotype.

PubMed

Larsson, Maria; Hedner, Margareta; Papenberg, Goran; Seubert, Janina; Bäckman, Lars; Laukka, Erika J

2016-02-01

The neuroanatomical organization that underlies olfactory memory is different from that of other memory types. The present work examines olfactory memory in an elderly population-based sample (Swedish National Study on Aging and Care in Kungsholmen) aged 60-100 years (n = 2280). We used structural equation modeling to investigate whether olfactory memory in old age is best conceptualized as a distinct category, differentiated from episodic and semantic memory. Further, potential olfactory dedifferentiation and genetic associations (APOE) to olfactory function in late senescence were investigated. Results are in support of a 3-factor solution where olfactory memory, as indexed by episodic odor recognition and odor identification, is modeled separately from episodic and semantic memory for visual and verbal information. Increasing age was associated with poorer olfactory memory performance, and observed age-related deficits were further exacerbated for carriers of the APOE ε4 allele; these effects tended to be larger for olfactory memory compared to episodic and semantic memory pertaining to other sensory systems (vision, auditory). Finally, stronger correlations between olfactory and episodic memory, indicating dedifferentiation, were observed in the older age groups. Copyright © 2016 Elsevier Inc. All rights reserved.

[How we smell and what it means to us: basic principles of the sense of smell].

PubMed

Manzini, I; Frasnelli, J; Croy, I

2014-12-01

The origins of the sense of smell lie in the perception of environmental molecules and go back to unicellular organisms such as bacteria. Odors transmit a multitude of information about the chemical composition of our environment. The sense of smell helps people and animals with orientation in space, warns of potential threats, influences the choice of sexual partners, regulates food intake and influences feelings and social behavior in general. The perception of odors begins in sensory neurons residing in the olfactory epithelium that express G protein-coupled receptors, the so-called olfactory receptors. The binding of odor molecules to olfactory receptors initiates a signal transduction cascade that converts olfactory stimuli into electrical signals. These signals are then transmitted to the olfactory bulb, the first relay center in the olfactory pathway, via the axons of the sensory neurons. The olfactory information is processed in the bulb and then transferred to higher olfactory centers via axons of mitral cells, the bulbar projection neurons. This review describes the mechanisms involved in peripheral detection of odorants, outlines the further processing of olfactory information in higher olfactory centers and finally gives an overview of the overall significance of the ability to smell.

Olfaction in the autism spectrum.

PubMed

Galle, Sara A; Courchesne, Valérie; Mottron, Laurent; Frasnelli, Johannes

2013-01-01

The autism spectrum (AS) is characterised by enhanced perception in vision and audition, described by the enhanced perceptual functioning (EPF) model. This model predicts enhanced low-level (discrimination of psychophysical dimensions), and mid- and high-level (pattern detection and identification) perception. The EPF model is here tested for olfaction by investigating olfactory function in autistic and Asperger participants. Experiment 1 targeted higher-order olfactory processing by assessing olfactory identification in nine Asperger, ten autistic, and eleven typically developed individuals. Experiment 2 focused on low-level olfactory processing; we assessed odour detection thresholds and odour discrimination in five Asperger, five autistic, and five typically developed males. Olfactory identification was impaired in autistic participants relative to control and Asperger participants. Typical performance in low-level olfactory processing suggests that neural mechanisms involved in the perceptual phenotype of AS do not affect structures implicated in olfactory processing. Reduced olfactory identification is limited to autistic participants who displayed speech delay and may be due to a reduced facility to use verbal labels. The apparent absence of enhanced olfactory perception of AS participants distinguishes the olfactory system from the other sensory modalities and might be caused by the absence of an obligatory thalamic relay.

Olfactory organ of Octopus vulgaris: morphology, plasticity, turnover and sensory characterization

PubMed Central

Polese, Gianluca; Bertapelle, Carla

2016-01-01

ABSTRACT The cephalopod olfactory organ was described for the first time in 1844 by von Kölliker, who was attracted to the pair of small pits of ciliated cells on each side of the head, below the eyes close to the mantle edge, in both octopuses and squids. Several functional studies have been conducted on decapods but very little is known about octopods. The morphology of the octopus olfactory system has been studied, but only to a limited extent on post-hatching specimens, and the only paper on adult octopus gives a minimal description of the olfactory organ. Here, we describe the detailed morphology of young male and female Octopus vulgaris olfactory epithelium, and using a combination of classical morphology and 3D reconstruction techniques, we propose a new classification for O. vulgaris olfactory sensory neurons. Furthermore, using specific markers such as olfactory marker protein (OMP) and proliferating cell nuclear antigen (PCNA) we have been able to identify and differentially localize both mature olfactory sensory neurons and olfactory sensory neurons involved in epithelium turnover. Taken together, our data suggest that the O. vulgaris olfactory organ is extremely plastic, capable of changing its shape and also proliferating its cells in older specimens. PMID:27069253

Multidisciplinary, interdisciplinary, or dysfunctional? Team working in mixed-methods research.

PubMed

O'Cathain, Alicia; Murphy, Elizabeth; Nicholl, Jon

2008-11-01

Combining qualitative and quantitative methods in a single study-otherwise known as mixed-methods research-is common. In health research these projects can be delivered by research teams. A typical scenario, for example, involves medical sociologists delivering qualitative components and researchers from medicine or health economics delivering quantitative components. We undertook semistructured interviews with 20 researchers who had worked on mixed-methods studies in health services research to explore the facilitators of and barriers to exploiting the potential of this approach. Team working emerged as a key issue, with three models of team working apparent: multidisciplinary, interdisciplinary, and dysfunctional. Interdisciplinary research was associated with integration of data or findings from the qualitative and quantitative components in both the final reports and the peer-reviewed publications. Methodological respect between team members and a principal investigator who valued integration emerged as essential to achieving integrated research outcomes.

Exercise Is Associated with Lower Long-Term Risk of Olfactory Impairment in Older Adults

PubMed Central

Schubert, Carla R.; Cruickshanks, Karen J.; Nondahl, David M.; Klein, Barbara EK; Klein, Ronald; Fischer, Mary E.

2013-01-01

Importance The prevalence of olfactory impairment is high in older adults and this decline in olfactory ability may pose health and safety risks, affect nutrition and decrease quality of life. It is important to identify modifiable risk factors to reduce the burden of olfactory impairment in aging populations. Objectives To determine if exercise is associated with the 10-year cumulative incidence of olfactory impairment. Design, Setting and Participants Observational longitudinal population-based Epidemiology of Hearing Loss Study. Participants without olfactory impairment (n=1611) were ages 53-97 years at baseline and were followed for up to ten years (1998-2010). Interventions None Main Outcome and Measures Olfaction was measured with the San Diego Odor Identification Test at three examinations (1998-2000, 2003-2005, 2009-2010) of the Epidemiology of Hearing Loss Study. The main outcome was the incidence of olfactory impairment five (2003-2005) or ten (2009-2010) years later and the association of baseline exercise with the long-term risk of developing olfactory impairment. Results The 10-year cumulative incidence of olfactory impairment was 27.6% (95% confidence interval =25.3, 29.9) and rates varied by age and sex; those who were older (Hazard Ratio =1.88, 95% Confidence Interval=1.74, 2.03, for every 5 years) or male (Hazard Ratio=1.27, 95% Confidence Interval=1.00, 1.61) had an increased risk of olfactory impairment. Participants who reported exercising at least once a week long enough to work up a sweat had a decreased risk of olfactory impairment (age and sex adjusted Hazard Ratio= 0.76, 95% CI= 0.60, 0.97). Increasing frequency of exercise was associated with decreasing risk of developing olfactory impairment (p for trend = 0.02). Conclusion and Relevance Regular exercise was associated with lower 10-year cumulative incidence of olfactory impairment. Older adults who exercise may be able to retain olfactory function with age. PMID:24135745

The role of olfaction throughout juvenile development: functional adaptations in elasmobranchs.

PubMed

Schluessel, Vera; Bennett, Michael B; Bleckmann, Horst; Collin, Shaun P

2010-04-01

Seven elasmobranch species, a group known for their highly-developed sense of smell, were examined for developmental changes in the number of olfactory lamellae, the size of the surface area of the sensory olfactory epithelium and the mass of both the olfactory rosettes (primary input to the CNS), and the olfactory bulbs. Within each species, juveniles possessed miniature versions of the adult olfactory organs, visually not distinguishable from these and without any obvious structural differences (e.g., with respect to the number of lamellae and the extent of secondary folding) between differently sized individuals. The size of the olfactory organs was positively correlated with body length and body mass, although few species showed proportional size scaling. In Aetobatus narinari and Aptychotrema rostrata, olfactory structures increased in proportion to body size. With respect to the growth of the olfactory bulb, all species showed allometric but not proportional growth. Olfaction may be of particular importance to juveniles in general, which are often subjected to heavy predation rates and fierce inter/intraspecific competition. Accordingly, it would be advantageous to possess a fully functional olfactory system early on in development. Slow growth rates of olfactory structures could then be attributed to a greater reliance on other sensory systems with increasing age or simply be regarded as maintaining an already optimized olfactory system. (c) 2009 Wiley-Liss, Inc.

Olfactory acuity in theropods: palaeobiological and evolutionary implications.

PubMed

Zelenitsky, Darla K; Therrien, François; Kobayashi, Yoshitsugu

2009-02-22

This research presents the first quantitative evaluation of the olfactory acuity in extinct theropod dinosaurs. Olfactory ratios (i.e. the ratio of the greatest diameter of the olfactory bulb to the greatest diameter of the cerebral hemisphere) are analysed in order to infer the olfactory acuity and behavioural traits in theropods, as well as to identify phylogenetic trends in olfaction within Theropoda. A phylogenetically corrected regression of olfactory ratio to body mass reveals that, relative to predicted values, the olfactory bulbs of (i) tyrannosaurids and dromaeosaurids are significantly larger, (ii) ornithomimosaurs and oviraptorids are significantly smaller, and (iii) ceratosaurians, allosauroids, basal tyrannosauroids, troodontids and basal birds are within the 95% CI. Relative to other theropods, olfactory acuity was high in tyrannosaurids and dromaeosaurids and therefore olfaction would have played an important role in their ecology, possibly for activities in low-light conditions, locating food, or for navigation within large home ranges. Olfactory acuity was the lowest in ornithomimosaurs and oviraptorids, suggesting a reduced reliance on olfaction and perhaps an omnivorous diet in these theropods. Phylogenetic trends in olfaction among theropods reveal that olfactory acuity did not decrease in the ancestry of birds, as troodontids, dromaeosaurids and primitive birds possessed typical or high olfactory acuity. Thus, the sense of smell must have remained important in primitive birds and its presumed decrease associated with the increased importance of sight did not occur until later among more derived birds.

Olfactory acuity in theropods: palaeobiological and evolutionary implications

PubMed Central

Zelenitsky, Darla K.; Therrien, François; Kobayashi, Yoshitsugu

2008-01-01

This research presents the first quantitative evaluation of the olfactory acuity in extinct theropod dinosaurs. Olfactory ratios (i.e. the ratio of the greatest diameter of the olfactory bulb to the greatest diameter of the cerebral hemisphere) are analysed in order to infer the olfactory acuity and behavioural traits in theropods, as well as to identify phylogenetic trends in olfaction within Theropoda. A phylogenetically corrected regression of olfactory ratio to body mass reveals that, relative to predicted values, the olfactory bulbs of (i) tyrannosaurids and dromaeosaurids are significantly larger, (ii) ornithomimosaurs and oviraptorids are significantly smaller, and (iii) ceratosaurians, allosauroids, basal tyrannosauroids, troodontids and basal birds are within the 95% CI. Relative to other theropods, olfactory acuity was high in tyrannosaurids and dromaeosaurids and therefore olfaction would have played an important role in their ecology, possibly for activities in low-light conditions, locating food, or for navigation within large home ranges. Olfactory acuity was the lowest in ornithomimosaurs and oviraptorids, suggesting a reduced reliance on olfaction and perhaps an omnivorous diet in these theropods. Phylogenetic trends in olfaction among theropods reveal that olfactory acuity did not decrease in the ancestry of birds, as troodontids, dromaeosaurids and primitive birds possessed typical or high olfactory acuity. Thus, the sense of smell must have remained important in primitive birds and its presumed decrease associated with the increased importance of sight did not occur until later among more derived birds. PMID:18957367

Olfactory receptor neuron profiling using sandalwood odorants.

PubMed

Bieri, Stephan; Monastyrskaia, Katherine; Schilling, Boris

2004-07-01

The mammalian olfactory system can discriminate between volatile molecules with subtle differences in their molecular structures. Efforts in synthetic chemistry have delivered a myriad of smelling compounds of different qualities as well as many molecules with very similar olfactive properties. One important class of molecules in the fragrance industry are sandalwood odorants. Sandalwood oil and four synthetic sandalwood molecules were selected to study the activation profile of endogenous olfactory receptors when exposed to compounds from the same odorant family. Dissociated rat olfactory receptor neurons were exposed to the sandalwood molecules and the receptor activation studied by monitoring fluxes in the internal calcium concentration. Olfactory receptor neurons were identified that were specifically stimulated by sandalwood compounds. These neurons expressed olfactory receptors that can discriminate between sandalwood odorants with slight differences in their molecular structures. This is the first study in which an important class of perfume compounds was analyzed for its ability to activate endogenous olfactory receptors in olfactory receptor neurons.

Relationship between uninasal anatomy and uninasal olfactory ability.

PubMed

Hornung, D E; Leopold, D A

1999-01-01

To examine the relationship between uninasal anatomy and olfactory ability. A stepwise analysis of variance was used to regress the logarithm of the percentage of correct responses on the Odorant Confusion Matrix (a measure of olfactory ability) against the logarithm of nasal volume measurements determined from computed tomographic scans. Nineteen patients with hyposmia whose olfactory losses were thought to be related to conductive disorders. After correcting for sex differences, a mathematical model was developed in which the volume of 6 regions of the nasal cavity, 6 first-order interactions, and 3 second-order interactions accounted for 97% of the variation in the measure of olfactory ability. Increases in the size of compartments of the nasal cavity around the olfactory cleft generally increase olfactory ability. Also, anatomical differences in the nasal cavities of men and women may account, in part, for sex differences in olfactory ability.

Modern psychophysical tests to assess olfactory function.

PubMed

Eibenstein, A; Fioretti, A B; Lena, C; Rosati, N; Amabile, G; Fusetti, M

2005-07-01

The sense of smell significantly contributes to quality of life. In recent years much progress has been made in understanding the biochemistry, physiology and pathology of the human olfactory system. Olfactory disorders may arise not only from upper airway phlogosis but also from neurodegenerative disease. Hyposmia may precede motor signs in Parkinson's disease and cognitive deficit in Alzheimer's disease. These findings suggest the complementary role of olfactory tests in the diagnosis and management of neurodegenerative diseases. In this report we present a review of modern olfactory tests and their clinical applications. Although rarely employed in routine clinical practice, the olfactory test evaluates the ability of odour identification and is a useful diagnostic tool for olfaction evaluation. Olfactory screening tests are also available. In this work we strongly recommend the importance of an ENT evaluation before the test administration and dissuade from a self-administration of an olfactory test.

Linking local circuit inhibition to olfactory behavior: a critical role for granule cells in olfactory discrimination.

PubMed

Strowbridge, Ben W

2010-02-11

In this issue of Neuron, Abraham et al. report a direct connection between inhibitory function and olfactory behavior. Using molecular methods to alter glutamate receptor subunit composition in olfactory bulb granule cells, the authors found a selective modulation in the time required for difficult, but not simple, olfactory discrimination tasks. Copyright 2010 Elsevier Inc. All rights reserved.

Calcium Signaling in Mitral Cell Dendrites of Olfactory Bulbs of Neonatal Rats and Mice during Olfactory Nerve Stimulation and Beta-Adrenoceptor Activation

ERIC Educational Resources Information Center

Yuan, Qi; Mutoh, Hiroki; Debarbieux, Franck; Knopfel, Thomas

2004-01-01

Synapses formed by the olfactory nerve (ON) provide the source of excitatory synaptic input onto mitral cells (MC) in the olfactory bulb. These synapses, which relay odor-specific inputs, are confined to the distally tufted single primary dendrites of MCs, the first stage of central olfactory processing. Beta-adrenergic modulation of electrical…

Lesion of the Olfactory Epithelium Accelerates Prion Neuroinvasion and Disease Onset when Prion Replication Is Restricted to Neurons

PubMed Central

Crowell, Jenna; Wiley, James A.; Bessen, Richard A.

2015-01-01

Natural prion diseases of ruminants are moderately contagious and while the gastrointestinal tract is the primary site of prion agent entry, other mucosae may be entry sites in a subset of infections. In the current study we examined prion neuroinvasion and disease induction following disruption of the olfactory epithelium in the nasal mucosa since this site contains environmentally exposed olfactory sensory neurons that project directly into the central nervous system. Here we provide evidence for accelerated prion neuroinvasion and clinical onset from the olfactory mucosa after disruption and regeneration of the olfactory epithelium and when prion replication is restricted to neurons. In transgenic mice with neuron restricted replication of prions, there was a reduction in survival when the olfactory epithelium was disrupted prior to intranasal inoculation and there was >25% decrease in the prion incubation period. In a second model, the neurotropic DY strain of transmissible mink encephalopathy was not pathogenic in hamsters by the nasal route, but 50% of animals exhibited brain infection and/or disease when the olfactory epithelium was disrupted prior to intranasal inoculation. A time course analysis of prion deposition in the brain following loss of the olfactory epithelium in models of neuron-restricted prion replication suggests that neuroinvasion from the olfactory mucosa is via the olfactory nerve or brain stem associated cranial nerves. We propose that induction of neurogenesis after damage to the olfactory epithelium can lead to prion infection of immature olfactory sensory neurons and accelerate prion spread to the brain. PMID:25822718

Effects of 20 mg oral Δ9-tetrahydrocannabinol on the olfactory function of healthy volunteers*

PubMed Central

Walter, Carmen; Oertel, Bruno G; Ludyga, Dagmar; Ultsch, Alfred; Hummel, Thomas; Lötsch, Jörn

2014-01-01

Aims Olfactory loss impairs the patient's quality of life. In individualized therapies, olfactory drug effects gain clinical importance. Molecular evidence suggests that among drugs with potential olfactory effects is Δ9-tetrahydrocannabinol (THC), which is approved for several indications, including neuropathic pain or analgesia in cancer patients. The present study aimed at assessing the olfactory effects of THC to be expected during analgesic treatment. Methods The effects of 20 mg oral THC on olfaction were assessed in a placebo-controlled, randomized cross-over study in healthy volunteers. Using an established olfactory test (Sniffin' Sticks), olfactory thresholds, odour discrimination and odour identification were assessed in 15 subjects at baseline and 2 h after THC administration. Results Δ9-Tetrahydrocannabinol impaired the performance of subjects (n = 15) in the olfactory test. Specifically, olfactory thresholds were increased and odour discrimination performance was reduced. This resulted in a significant drop in composite threshold, discrimination, identification (TDI) olfactory score by 5.5 points (from 37.7 ± 4.2 to 32.2 ± 5.6, 95% confidence interval for differences THC vs. placebo, −7.8 to −2.0, P = 0.003), which is known to be a subjectively perceptible impairment of olfactory function. Conclusions Considering the resurgence of THC in medical use for several pathological conditions, the present results indicate that THC-based analgesics may be accompanied by subjectively noticeable reductions in olfactory acuity. In particular, for patients relying on their sense of smell, this might be relevant information for personalized therapy strategies. PMID:24802974

Effects of 20 mg oral Δ(9) -tetrahydrocannabinol on the olfactory function of healthy volunteers.

PubMed

Walter, Carmen; Oertel, Bruno G; Ludyga, Dagmar; Ultsch, Alfred; Hummel, Thomas; Lötsch, Jörn

2014-11-01

Olfactory loss impairs the patient's quality of life. In individualized therapies, olfactory drug effects gain clinical importance. Molecular evidence suggests that among drugs with potential olfactory effects is Δ(9) -tetrahydrocannabinol (THC), which is approved for several indications, including neuropathic pain or analgesia in cancer patients. The present study aimed at assessing the olfactory effects of THC to be expected during analgesic treatment. The effects of 20 mg oral THC on olfaction were assessed in a placebo-controlled, randomized cross-over study in healthy volunteers. Using an established olfactory test (Sniffin' Sticks), olfactory thresholds, odour discrimination and odour identification were assessed in 15 subjects at baseline and 2 h after THC administration. Δ(9) -Tetrahydrocannabinol impaired the performance of subjects (n = 15) in the olfactory test. Specifically, olfactory thresholds were increased and odour discrimination performance was reduced. This resulted in a significant drop in composite threshold, discrimination, identification (TDI) olfactory score by 5.5 points (from 37.7 ± 4.2 to 32.2 ± 5.6, 95% confidence interval for differences THC vs. placebo, -7.8 to -2.0, P = 0.003), which is known to be a subjectively perceptible impairment of olfactory function. Considering the resurgence of THC in medical use for several pathological conditions, the present results indicate that THC-based analgesics may be accompanied by subjectively noticeable reductions in olfactory acuity. In particular, for patients relying on their sense of smell, this might be relevant information for personalized therapy strategies. © 2014 The British Pharmacological Society.

Single olfactory organ associated with prosencephalic malformation and cyclopia in a Xenopus laevis tadpole.

PubMed

Magrassi, L; Graziadei, P P

1987-06-02

A cyclops Xenopus laevis tadpole with a single olfactory organ is described. At a stage comparable to 48, the telencephalon was severely atrophic and only the region where the olfactory fibres terminated appeared to have the cytoarchitecture of the olfactory bulb. In this animal the central nervous system (CNS) appeared normally developed only posterior to the preoptic area. The hypothesis of a diencephalic origin of the region where the olfactory fibres terminated is discussed in the light of our previous results of olfactory placode transplantation. By analogy between this case and other malformations (cyclopia, holoprosencephaly) in higher vertebrates and humans, the need is emphasized for a more precise anatomical description of the olfactory input in related malformations.

Olfactory gene expression in migrating adult sockeye salmon Oncorhynchus nerka.

PubMed

Bett, N N; Hinch, S G; Kaukinen, K H; Li, S; Miller, K M

2018-04-16

Expression of 12 olfactory genes was analysed in adult sockeye salmon Oncorhynchus nerka nearing spawning grounds and O. nerka that had strayed from their natal migration route. Variation was found in six of these genes, all of which were olfc olfactory receptors and had lower expression levels in salmon nearing spawning grounds. The results may reflect decreased sensitivity to natal water olfactory cues as these fish are no longer seeking the correct migratory route. The expression of olfactory genes during the olfactory-mediated spawning migration of Pacific salmon Oncorhynchus spp. is largely unexplored and these findings demonstrate a link between migratory behaviours and olfactory plasticity that provides a basis for future molecular research on salmon homing. © 2018 The Fisheries Society of the British Isles.

Locus coeruleus degeneration exacerbates olfactory deficits in APP/PS1 transgenic mice.

PubMed

Rey, Nolwen L; Jardanhazi-Kurutz, Daniel; Terwel, Dick; Kummer, Markus P; Jourdan, Francois; Didier, Anne; Heneka, Michael T

2012-02-01

Neuronal loss in the locus coeruleus (LC) is 1 of the early pathological events in Alzheimer's disease (AD). Projections of noradrenergic neurons of the LC innervate the olfactory bulb (OB). Because olfactory deficits have been reported in early AD, we investigated the effect of induced LC degeneration on olfactory memory and discrimination in an AD mouse model. LC degeneration was induced by treating APP/PS1 mice with N-(2-chloroethyl)-N-ethyl-bromo-benzylamine (DSP4) repeatedly between 3 and 12 months of age. Short term odor retention, ability for spontaneous habituation to an odor, and spontaneous odor discrimination were assessed by behavioral tests. DSP4 treatment in APP/PS1 mice resulted in an exacerbation of short term olfactory memory deficits and more discrete weakening of olfactory discrimination abilities, suggesting that LC degeneration contributes to olfactory deficits observed in AD. Importantly, DSP4 treatment also increased amyloid β (Aβ) deposition in the olfactory bulb of APP/PS1 mice, which correlated with olfactory memory, not with discrimination deficits. Copyright © 2012 Elsevier Inc. All rights reserved.

Olfactory epithelium changes in germfree mice

PubMed Central

François, Adrien; Grebert, Denise; Rhimi, Moez; Mariadassou, Mahendra; Naudon, Laurent; Rabot, Sylvie; Meunier, Nicolas

2016-01-01

Intestinal epithelium development is dramatically impaired in germfree rodents, but the consequences of the absence of microbiota have been overlooked in other epithelia. In the present study, we present the first description of the bacterial communities associated with the olfactory epithelium and explored differences in olfactory epithelium characteristics between germfree and conventional, specific pathogen-free, mice. While the anatomy of the olfactory epithelium was not significantly different, we observed a thinner olfactory cilia layer along with a decreased cellular turn-over in germfree mice. Using electro-olfactogram, we recorded the responses of olfactory sensitive neuronal populations to various odorant stimulations. We observed a global increase in the amplitude of responses to odorants in germfree mice as well as altered responses kinetics. These changes were associated with a decreased transcription of most olfactory transduction actors and of olfactory xenobiotic metabolising enzymes. Overall, we present here the first evidence that the microbiota modulates the physiology of olfactory epithelium. As olfaction is a major sensory modality for most animal species, the microbiota may have an important impact on animal physiology and behaviour through olfaction alteration. PMID:27089944

Neurotoxicity following acute inhalation of aerosols generated during resistance spot weld-bonding of carbon steel

PubMed Central

Sriram, Krishnan; Jefferson, Amy M.; Lin, Gary X.; Afshari, Aliakbar; Zeidler-Erdely, Patti C.; Meighan, Terence G.; McKinney, Walter; Jackson, Mark; Cumpston, Amy; Cumpston, Jared L.; Leonard, Howard D.; Frazer, David G.; Antonini, James M.

2015-01-01

Welding generates complex metal aerosols, inhalation of which is linked to adverse health effects among welders. An important health concern of welding fume (WF) exposure is neurological dysfunction akin to Parkinson’s disease (PD). Some applications in manufacturing industry employ a variant welding technology known as “weld-bonding” that utilizes resistance spot welding, in combination with adhesives, for metal-to-metal welding. The presence of adhesives raises additional concerns about worker exposure to potentially toxic components like Methyl Methacrylate, Bisphenol A and volatile organic compounds (VOCs). Here, we investigated the potential neurotoxicological effects of exposure to welding aerosols generated during weld-bonding. Male Sprague–Dawley rats were exposed (25 mg/m3 targeted concentration; 4 h/day × 13 days) by whole-body inhalation to filtered air or aerosols generated by either weld-bonding with sparking (high metal, low VOCs; HM) or without sparking (low metal; high VOCs; LM). Fumes generated under these conditions exhibited complex aerosols that contained both metal oxide particulates and VOCs. LM aerosols contained a greater fraction of VOCs than HM, which comprised largely metal particulates of ultrafine morphology. Short-term exposure to LM aerosols caused distinct changes in the levels of the neurotransmitters, dopamine (DA) and serotonin (5-HT), in various brain areas examined. LM aerosols also specifically decreased the mRNA expression of the olfactory marker protein (Omp) and tyrosine hydroxylase (Th) in the olfactory bulb. Consistent with the decrease in Th, LM also reduced the expression of dopamine transporter (Slc6a3; Dat), as well as, dopamine D2 receptor (Drd2) in the olfactory bulb. In contrast, HM aerosols induced the expression of Th and dopamine D5 receptor (Drd5) mRNAs, elicited neuroinflammation and blood–brain barrier-related changes in the olfactory bulb, but did not alter the expression of Omp. Our findings divulge the differential effects of LM and HM aerosols in the brain and suggest that exposure to weld-bonding aerosols can potentially elicit neurotoxicity following a short-term exposure. However, further investigations are warranted to determine if the aerosols generated by weld-bonding can contribute to persistent long-term neurological deficits and/or neurodegeneration. PMID:25265048

Ulex europaeus I and glycine max bind to the human olfactory bulb.

PubMed

Nagao, M; Oka, N; Kamo, H; Akiguchi, I; Kimura, J

1993-12-24

The distribution of binding sites for the fucose-selective lectin Ulex europaeus I and the terminal N-acetylgalactosamine-selective lectin glycine max in the human olfactory bulb were studied. These lectins bound to primary olfactory axons in the olfactory nerve layer and the glomerular layer. They also bound to fibers located in the deeper layers such as the external plexiform layer and the granular layer. Furthermore they projected to the olfactory stalk but not in the cerebrum. The deeper projections of the lectin binding fibers may affect the function of the olfactory bulb in humans.

Meanings of thinness and dysfunctional eating in black South African females: a qualitative study.

PubMed

Morris, P F; Szabo, C P

2013-09-01

This study qualitatively explored local meanings of thinness and dysfunctional eating in black adolescent females in the rapidly westernizing socio-cultural context of post-apartheid South Africa. Four (n=4) urban state highschools in KwaZulu-Natal were selected from which 40 subjects were sampled from Grades 9-12. Focus groups were conducted following a semi-structured interview and analysed using Constant Comparative Analysis. Subjects reported a wide range of different meanings for thinness, which included traditional idioms of distress and typically western pressures towards thinness, which was particularly evident in the multicultural schools. Subjects also reported a wide range of dysfunctional eating practices (such as purging) which were underscored by a wide range of motivations, including traditional practices and western body image concern; and which did not tend to follow patterns of 'dieting' that are typical in affluent, western societies. Western pressures towards thinness may be blending with traditional idioms of distress and culturally sanctioned rituals of remedial purging and social over-eating, thereby placing this group at particular risk for a range of dysfunctional eating patterns that may not follow typically western paradigms or diagnostic systems.

Olfactory epithelium: Cells, clinical disorders, and insights from an adult stem cell niche

PubMed Central

Choi, Rhea

2018-01-01

Disorders causing a loss of the sense of smell remain a therapeutic challenge. Basic research has, however, greatly expanded our knowledge of the organization and function of the olfactory system. This review describes advances in our understanding of the cellular components of the peripheral olfactory system, specifically the olfactory epithelium in the nose. The article discusses recent findings regarding the mechanisms involved in regeneration and cellular renewal from basal stem cells in the adult olfactory epithelium, considering the strategies involved in embryonic olfactory development and insights from research on other stem cell niches. In the context of clinical conditions causing anosmia, the current view of adult olfactory neurogenesis, tissue homeostasis, and failures in these processes is considered, along with current and future treatment strategies. Level of Evidence NA PMID:29492466

Regulation of inflammation-associated olfactory neuronal death and regeneration by the type II tumor necrosis factor receptor.

PubMed

Pozharskaya, Tatyana; Liang, Jonathan; Lane, Andrew P

2013-09-01

Olfactory loss is a debilitating symptom of chronic rhinosinusitis. To study the impact of inflammation on the olfactory system, the inducible olfactory inflammation (IOI) transgenic mouse was created in which inflammation can be turned on and off within the olfactory epithelium. In this study, the type II tumor necrosis factor (TNF) receptor (TNFR2) was knocked out, and the effect on the olfactory loss phenotype was assessed. IOI mice were bred to TNFR2 knockout mice to yield progeny IOI mice lacking the TNFR2 receptor (TNFR2(-/-) ). TNF-α expression was induced within the olfactory epithelium for 6 weeks to generate chronic inflammation. Olfactory function was assayed by electro-olfactogram (EOG), and olfactory tissue was processed for histology and immunohistochemical staining. Compared to IOI mice with wild-type TNFR2, IOI mice lacking the TNFR2 demonstrated similar levels of inflammatory infiltration and enlargement of the subepithelial layer. However, IOI-TNFR2(-/-) mice differed markedly in that the neuronal layer was largely preserved and active progenitor cell proliferation was present. Odorant responses were maintained in the IOI-TNFR2(-/-) mice, in contrast to IOI mice. TNFR2 is the minor receptor for TNF-α, but appears to play an important role in mediating TNF-induced disruption of the olfactory system. This finding suggests that neuronal death and inhibition of proliferation in CRS may be mediated by TNFR2 on olfactory neurons and progenitor cells. Further studies are needed to elucidate the subcellular pathways involved and develop novel therapies for treating olfactory loss in the setting of CRS. © 2013 ARS-AAOA, LLC.

Alterations of brain grey matter density and olfactory bulb volume in patients with olfactory loss after traumatic brain injury.

PubMed

Han, Pengfei; Winkler, Nicole; Hummel, Cornelia; Hähner, Antje; Gerber, Johannes; Hummel, Thomas

2018-04-27

Olfactory loss and traumatic brain injury (TBI) both lead to anatomical brain alterations in humans. Little research has been done on the structural brain changes for TBI patients with olfactory loss. Using voxel-based morphometry, the grey matter (GM) density was examined for twenty-two TBI patients with hyposmia, twenty-four TBI patients with anosmia, and twenty-two age-matched controls. Olfactory bulb (OB) volumes were measured by manual segmentation of acquired T2 weighted coronal slices using a standardized protocol. Brain lesions in the olfactory relevant areas were also examined for TBI patients. Results showed that patients with anosmia have more frequent lesions in the OB, orbitofrontal cortex (OFC) and the temporal lobe pole, as compared to patients with hyposmia. GM density in the primary olfactory area was decreased in both groups of patients. In addition, compared to controls, patients with anosmia showed GM density reduction in several secondary olfactory eloquent regions, including the gyrus rectus, medial OFC, anterior cingulate cortex, insula, and cerebellum. However, patients with hyposmia showed a lesser degree of GM reduction compared to healthy controls. Smaller OB volumes were found for patients with olfactory loss as compared to controls. TBI patients with anosmia had the smallest OB volumes which were caused by the lesions for OB. In addition, post-TBI duration was negatively correlated with GM density in the secondary olfactory areas in patients with hyposmia, but was positively correlated with GM density in the frontal and temporal gyrus in patients with anosmia. The GM density and OB volume reduction among TBI patients with olfactory loss was largely depend on the location and severity of brain lesions in olfactory relevant regions. Longer post-TBI duration had an impact on brain GM density changes, which indicate a decreased olfactory function in patients with hyposmia and possible compensatory mechanisms in patients with anosmia.

Effect of basal forebrain stimulation on extracellular acetylcholine release and blood flow in the olfactory bulb.

PubMed

Uchida, Sae; Kagitani, Fusako

2017-05-12

The olfactory bulb receives cholinergic basal forebrain input, as does the neocortex; however, the in vivo physiological functions regarding the release of extracellular acetylcholine and regulation of regional blood flow in the olfactory bulb are unclear. We used in vivo microdialysis to measure the extracellular acetylcholine levels in the olfactory bulb of urethane-anesthetized rats. Focal chemical stimulation by microinjection of L-glutamate into the horizontal limb of the diagonal band of Broca (HDB) in the basal forebrain, which is the main source of cholinergic input to the olfactory bulb, increased extracellular acetylcholine release in the ipsilateral olfactory bulb. When the regional cerebral blood flow was measured using laser speckle contrast imaging, the focal chemical stimulation of the HDB did not significantly alter the blood flow in the olfactory bulb, while increases were observed in the neocortex. Our results suggest a functional difference between the olfactory bulb and neocortex regarding cerebral blood flow regulation through the release of acetylcholine by cholinergic basal forebrain input.

Olfactory projection neuron pathways in two species of marine Isopoda (Peracarida, Malacostraca, Crustacea).

PubMed

Stemme, Torben; Eickhoff, René; Bicker, Gerd

2014-08-01

The neuroanatomy of the olfactory pathway has been intensely studied in many representatives of Malacostraca. Nevertheless, the knowledge about bilateral olfactory integration pathways is mainly based on Decapoda. Here, we investigated the olfactory projection neuron pathway of two marine isopod species, Saduria entomon and Idotea emarginata, by lipophilic dye injections into the olfactory neuropil. We show that both arms of the olfactory globular tract form a chiasm in the center of the brain, as known from several other crustaceans. Furthermore, the olfactory projection neurons innervate both the medulla terminalis and the hemiellipsoid body of the ipsi- and the contralateral hemisphere. Both protocerebral neuropils are innervated to a comparable extent. This is reminiscent of the situation in the basal decapod taxon Dendrobranchiata. Thus, we propose that an innervation by the olfactory globular tract of both the medulla terminalis and the hemiellipsoid body is characteristic of the decapod ground pattern, but also of the ground pattern of Caridoida. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preprocessing of emotional visual information in the human piriform cortex.

PubMed

Schulze, Patrick; Bestgen, Anne-Kathrin; Lech, Robert K; Kuchinke, Lars; Suchan, Boris

2017-08-23

This study examines the processing of visual information by the olfactory system in humans. Recent data point to the processing of visual stimuli by the piriform cortex, a region mainly known as part of the primary olfactory cortex. Moreover, the piriform cortex generates predictive templates of olfactory stimuli to facilitate olfactory processing. This study fills the gap relating to the question whether this region is also capable of preprocessing emotional visual information. To gain insight into the preprocessing and transfer of emotional visual information into olfactory processing, we recorded hemodynamic responses during affective priming using functional magnetic resonance imaging (fMRI). Odors of different valence (pleasant, neutral and unpleasant) were primed by images of emotional facial expressions (happy, neutral and disgust). Our findings are the first to demonstrate that the piriform cortex preprocesses emotional visual information prior to any olfactory stimulation and that the emotional connotation of this preprocessing is subsequently transferred and integrated into an extended olfactory network for olfactory processing.

Quality-space theory in olfaction

PubMed Central

Young, Benjamin D.; Keller, Andreas; Rosenthal, David

2014-01-01

Quality-space theory (QST) explains the nature of the mental qualities distinctive of perceptual states by appeal to their role in perceiving. QST is typically described in terms of the mental qualities that pertain to color. Here we apply QST to the olfactory modalities. Olfaction is in various respects more complex than vision, and so provides a useful test case for QST. To determine whether QST can deal with the challenges olfaction presents, we show how a quality space (QS) could be constructed relying on olfactory perceptible properties and the olfactory mental qualities then defined by appeal to that QS of olfactory perceptible properties. We also consider how to delimit the olfactory QS from other modalities. We further apply QST to the role that experience plays in refining our olfactory discriminative abilities and the occurrence of olfactory mental qualities in non-conscious olfactory states. QST is shown to be fully applicable to and useful for understanding the complex domain of olfaction. PMID:24474945

The Olfactory Mosaic: Bringing an Olfactory Network Together for Odor Perception.

PubMed

Courtiol, Emmanuelle; Wilson, Donald A

2017-01-01

Olfactory perception and its underlying neural mechanisms are not fixed, but rather vary over time, dependent on various parameters such as state, task, or learning experience. In olfaction, one of the primary sensory areas beyond the olfactory bulb is the piriform cortex. Due to an increasing number of functions attributed to the piriform cortex, it has been argued to be an associative cortex rather than a simple primary sensory cortex. In fact, the piriform cortex plays a key role in creating olfactory percepts, helping to form configural odor objects from the molecular features extracted in the nose. Moreover, its dynamic interactions with other olfactory and nonolfactory areas are also critical in shaping the olfactory percept and resulting behavioral responses. In this brief review, we will describe the key role of the piriform cortex in the larger olfactory perceptual network, some of the many actors of this network, and the importance of the dynamic interactions among the piriform-trans-thalamic and limbic pathways.

Enhanced self-administration of the CB1 receptor agonist WIN55,212-2 in olfactory bulbectomized rats: evaluation of possible serotonergic and dopaminergic underlying mechanisms

PubMed Central

Amchova, Petra; Kucerova, Jana; Giugliano, Valentina; Babinska, Zuzana; Zanda, Mary T.; Scherma, Maria; Dusek, Ladislav; Fadda, Paola; Micale, Vincenzo; Sulcova, Alexandra; Fratta, Walter; Fattore, Liana

2013-01-01

Depression has been associated with drug consumption, including heavy or problematic cannabis use. According to an animal model of depression and substance use disorder comorbidity, we combined the olfactory bulbectomy (OBX) model of depression with intravenous drug self-administration procedure to verify whether depressive-like rats displayed altered voluntary intake of the CB1 receptor agonist WIN55,212-2 (WIN, 12.5 μg/kg/infusion). To this aim, olfactory-bulbectomized (OBX) and sham-operated (SHAM) Lister Hooded rats were allowed to self-administer WIN by lever-pressing under a continuous [fixed ratio 1 (FR-1)] schedule of reinforcement in 2 h daily sessions. Data showed that both OBX and SHAM rats developed stable WIN intake; yet, responses in OBX were constantly higher than in SHAM rats soon after the first week of training. In addition, OBX rats took significantly longer to extinguish the drug-seeking behavior after vehicle substitution. Acute pre-treatment with serotonin 5HT1B receptor agonist, CGS-12066B (2.5–10 mg/kg), did not significantly modify WIN intake in OBX and SHAM Lister Hooded rats. Furthermore, acute pre-treatment with CGS-12066B (10 and 15 mg/kg) did not alter responses in parallel groups of OBX and SHAM Sprague Dawley rats self-administering methamphetamine under higher (FR-2) reinforcement schedule with nose-poking as operandum. Finally, dopamine levels in the nucleus accumbens (NAc) of OBX rats did not increase in response to a WIN challenge, as in SHAM rats, indicating a dopaminergic dysfunction in bulbectomized rats. Altogether, our findings suggest that a depressive-like state may alter cannabinoid CB1 receptor agonist-induced brain reward function and that a dopaminergic rather than a 5-HT1B mechanism is likely to underlie enhanced WIN self-administration in OBX rats. PMID:24688470

Loss of hfe function reverses impaired recognition memory caused by olfactory manganese exposure in mice.

PubMed

Ye, Qi; Kim, Jonghan

2015-03-01

Excessive manganese (Mn) in the brain promotes a variety of abnormal behaviors, including memory deficits, decreased motor skills and psychotic behavior resembling Parkinson's disease. Hereditary hemochromatosis (HH) is a prevalent genetic iron overload disorder worldwide. Dysfunction in HFE gene is the major cause of HH. Our previous study has demonstrated that olfactory Mn uptake is altered by HFE deficiency, suggesting that loss of HFE function could alter manganese-associated neurotoxicity. To test this hypothesis, Hfe-knockout (Hfe (-/-)) and wild-type (Hfe (+/+)) mice mice were intranasally-instilled with manganese chloride (MnCl2 5 mg/kg) or water daily for 3 weeks and examined for memory function. Olfactory Mn diminished both short-term recognition and spatial memory in Hfe (+/+) mice, as examined by novel object recognition task and Barnes maze test, respectively. Interestingly, Hfe (-/-) mice did not show impaired recognition memory caused by Mn exposure, suggesting a potential protective effect of Hfe deficiency against Mn-induced memory deficits. Since many of the neurotoxic effects of manganese are thought to result from increased oxidative stress, we quantified activities of anti-oxidant enzymes in the prefrontal cortex (PFC). Mn instillation decreased superoxide dismutase 1 (SOD1) activity in Hfe (+/+) mice, but not in Hfe (-/-) mice. In addition, Hfe deficiency up-regulated SOD1 and glutathione peroxidase activities. These results suggest a beneficial role of Hfe deficiency in attenuating Mn-induced oxidative stress in the PFC. Furthermore, Mn exposure reduced nicotinic acetylcholine receptor levels in the PFC, indicating that blunted acetylcholine signaling could contribute to impaired memory associated with intranasal manganese. Together, our model suggests that disrupted cholinergic system in the brain is involved in airborne Mn-induced memory deficits and loss of HFE function could in part prevent memory loss via a potential up-regulation of anti-oxidant enzymes in the PFC.

Dock and Pak regulate olfactory axon pathfinding in Drosophila.

PubMed

Ang, Lay-Hong; Kim, Jenny; Stepensky, Vitaly; Hing, Huey

2003-04-01

The convergence of olfactory axons expressing particular odorant receptor (Or) genes on spatially invariant glomeruli in the brain is one of the most dramatic examples of precise axon targeting in developmental neurobiology. The cellular and molecular mechanisms by which olfactory axons pathfind to their targets are poorly understood. We report here that the SH2/SH3 adapter Dock and the serine/threonine kinase Pak are necessary for the precise guidance of olfactory axons. Using antibody localization, mosaic analyses and cell-type specific rescue, we observed that Dock and Pak are expressed in olfactory axons and function autonomously in olfactory neurons to regulate the precise wiring of the olfactory map. Detailed analyses of the mutant phenotypes in whole mutants and in small multicellular clones indicate that Dock and Pak do not control olfactory neuron (ON) differentiation, but specifically regulate multiple aspects of axon trajectories to guide them to their cognate glomeruli. Structure/function studies show that Dock and Pak form a signaling pathway that mediates the response of olfactory axons to guidance cues in the developing antennal lobe (AL). Our findings therefore identify a central signaling module that is used by ONs to project to their cognate glomeruli.

Acetylcholine and Olfactory Perceptual Learning

ERIC Educational Resources Information Center

Wilson, Donald A.; Fletcher, Max L.; Sullivan, Regina M.

2004-01-01

Olfactory perceptual learning is a relatively long-term, learned increase in perceptual acuity, and has been described in both humans and animals. Data from recent electrophysiological studies have indicated that olfactory perceptual learning may be correlated with changes in odorant receptive fields of neurons in the olfactory bulb and piriform…

Measurement and Analysis of Olfactory Responses with the Aim of Establishing an Objective Diagnostic Method for Central Olfactory Disorders

NASA Astrophysics Data System (ADS)

Uno, Tominori; Wang, Li-Qun; Miwakeichi, Fumikazu; Tonoike, Mitsuo; Kaneda, Teruo

In order to establish a new diagnostic method for central olfactory disorders and to identify objective indicators, we measured and analyzed brain activities in the parahippocampal gyrus and uncus, region of responsibility for central olfactory disorders. The relationship between olfactory stimulation and brain response at region of responsibility can be examined in terms of fitted responses (FR). FR in these regions may be individual indicators of changes in brain olfactory responses. In the present study, in order to non-invasively and objectively measure olfactory responses, an odor oddball task was conducted on four healthy volunteers using functional magnetic resonance imaging (fMRI) and a odorant stimulator with blast-method. The results showed favorable FR and activation in the parahippocampal gyrus or uncus in all subjects. In some subjects, both the parahippocampal gyrus and uncus were activated. Furthermore, activation was also confirmed in the cingulate gyrus, middle frontal gyrus, precentral gyrus, postcentral gyrus, superior temporal gyrus and insula. The hippocampus and uncus are known to be involved in the olfactory disorders associated with early-stage Alzheimer's disease and other olfactory disorders. In the future, it will be necessary to further develop the present measurement and analysis method to clarify the relationship between central olfactory disorders and brain activities and establish objective indicators that are useful for diagnosis.

Emotional stimulation alters olfactory sensitivity and odor judgment.

PubMed

Pollatos, Olga; Kopietz, Rainer; Linn, Jennifer; Albrecht, Jessica; Sakar, Vehbi; Anzinger, Andrea; Schandry, Rainer; Wiesmann, Martin

2007-07-01

Emotions have a strong influence on the perception of visual and auditory stimuli. Only little is known about the relation between emotional stimulation and olfactory functions. The present study investigated the relationship between the presentation of affective pictures, olfactory functions, and sex. Olfactory performance was assessed in 32 subjects (16 male). Olfactory sensitivity was significantly reduced following unpleasant picture presentation for all subjects and following pleasant picture presentation for male subjects only. Pleasantness and intensity ratings of a neutral suprathreshold odor were related to the valence of the pictures: After unpleasant picture presentation, the odor was rated as less pleasant and more intense, whereas viewing positive pictures induced a significant increase in reported odor pleasantness. We conclude that inducing a negative emotional state reduces olfactory sensitivity. A relation to functional deviations within the primary olfactory cortices is discussed.

Nested Expression Domains for Odorant Receptors in Zebrafish Olfactory Epithelium

NASA Astrophysics Data System (ADS)

Weth, Franco; Nadler, Walter; Korsching, Sigrun

1996-11-01

The mapping of high-dimensional olfactory stimuli onto the two-dimensional surface of the nasal sensory epithelium constitutes the first step in the neuronal encoding of olfactory input. We have used zebrafish as a model system to analyze the spatial distribution of odorant receptor molecules in the olfactory epithelium by quantitative in situ hybridization. To this end, we have cloned 10 very divergent zebrafish odorant receptor molecules by PCR. Individual genes are expressed in sparse olfactory receptor neurons. Analysis of the position of labeled cells in a simplified coordinate system revealed three concentric, albeit overlapping, expression domains for the four odorant receptors analyzed in detail. Such regionalized expression should result in a corresponding segregation of functional response properties. This might represent the first step of spatial encoding of olfactory input or be essential for the development of the olfactory system.

High convergence of olfactory and vomeronasal influence in the telencephalon of the terrestrial salamander Plethodon shermani.

PubMed

Roth, F C; Laberge, F

2011-03-17

Previous work suggested that the telencephalic pathways of the main olfactory and vomeronasal systems of vertebrates are mostly isolated from each other, with the possible exception of convergence of the two systems into a small part of the olfactory amygdala. We tested the hypothesis of convergence between the main olfactory and vomeronasal systems by investigating the physiology of telencephalic olfactory responses in an in vitro brain preparation of the salamander Plethodon shermani. This animal was chosen because its olfactory and vomeronasal nerves can be separated and stimulated independently. The nerves were stimulated by short current pulses delivered through suction electrodes. Evoked field potentials and intracellular responses were systematically recorded in the telencephalon. The results showed an abundant overlap of olfactory and vomeronasal nerve-evoked field potentials in the ipsilateral lateral telencephalon and the amygdala. Single neurons receiving bimodal main olfactory and vomeronasal input were found in the dorsolateral telencephalon and amygdala. A classification of response latencies suggested that a subset of these neurons received direct input from both the main and accessory olfactory bulbs. Unimodal excitatory main olfactory responses were mostly found in neurons of the caudal telencephalic pole, but were also present in the striato-pallial transition area/lateral pallium region and striatum. Unimodal excitatory vomeronasal responses were found in neurons of the striato-pallial transition area, vomeronasal amygdala, and caudal amygdala. We conclude that the main olfactory and vomeronasal systems are extensively integrated within the salamander telencephalon and probably act in concert to modulate behavior. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

Office procedures for quantitative assessment of olfactory function.

PubMed

Doty, Richard L

2007-01-01

Despite the importance of the sense of smell for establishing the flavor of foods and beverages, as well as protecting against environmental dangers, this primary sensory system is commonly ignored by the rhinologist. In this article basic issues related to practical measurement of olfactory function in the clinic are described and examples of the application of the two most common paradigms for such measurement--odor identification and detection--are presented. A listing is made of the 27 olfactory tests currently used clinically, along with their strengths and weaknesses. A brief review of common nasosinus-related disorders for which quantitative olfactory testing has been performed is provided. Although many psychophysical tests are available for quantifying olfactory loss, it is apparent that a number are limited in terms of practicality, sensitivity, and reliability. In general, sensitivity and reliability are positively correlated with test length. Given the strengths of the more reliable forced-choice pyschophysical tests and the limitations of electrophysiological tests, the common distinction between "subjective" and "objective" tests is misleading and should not be used. Complete recovery of olfactory function, as measured quantitatively, rarely follows surgical or medical interventions in patients with rhinosinusitis. Given the availability of practical clinical olfactory tests, the modern rhinologist can easily quantify cranial nerve (CN) I function. The application of such tests has led to a new understanding of the effects of nasal disease on olfactory function. Except in cases of total or near-total nasal obstruction, olfactory and airway patency measures usually are unrelated, in accord with the concept that rhinosinusitis primarily influences olfactory function by apoptotic pathological changes within the olfactory neuroepithelium.

Non-auditory factors affecting urban soundscape evaluation.

PubMed

Jeon, Jin Yong; Lee, Pyoung Jik; Hong, Joo Young; Cabrera, Densil

2011-12-01

The aim of this study is to characterize urban spaces, which combine landscape, acoustics, and lighting, and to investigate people's perceptions of urban soundscapes through quantitative and qualitative analyses. A general questionnaire survey and soundwalk were performed to investigate soundscape perception in urban spaces. Non-auditory factors (visual image, day lighting, and olfactory perceptions), as well as acoustic comfort, were selected as the main contexts that affect soundscape perception, and context preferences and overall impressions were evaluated using an 11-point numerical scale. For qualitative analysis, a semantic differential test was performed in the form of a social survey, and subjects were also asked to describe their impressions during a soundwalk. The results showed that urban soundscapes can be characterized by soundmarks, and soundscape perceptions are dominated by acoustic comfort, visual images, and day lighting, whereas reverberance in urban spaces does not yield consistent preference judgments. It is posited that the subjective evaluation of reverberance can be replaced by physical measurements. The categories extracted from the qualitative analysis revealed that spatial impressions such as openness and density emerged as some of the contexts of soundscape perception. © 2011 Acoustical Society of America

Neural Correlates of Olfactory Learning: Critical Role of Centrifugal Neuromodulation

ERIC Educational Resources Information Center

Fletcher, Max L.; Chen, Wei R.

2010-01-01

The mammalian olfactory system is well established for its remarkable capability of undergoing experience-dependent plasticity. Although this process involves changes at multiple stages throughout the central olfactory pathway, even the early stages of processing, such as the olfactory bulb and piriform cortex, can display a high degree of…

Olfactory-triggered panic attacks among Khmer refugees: a contextual approach.

PubMed

Hinton, Devon; Pich, Vuth; Chhean, Dara; Pollack, Mark

2004-06-01

One hundred Khmer refugees attending a psychiatric clinic were surveyed to determine the prevalence of olfactory-triggered panic attacks as well as certain characteristics of the episodes, including trigger (i.e. type of odor), frequency, length, somatic symptoms, and the rate of associated flashbacks and catastrophic cognitions. Forty-five of the 100 patients had experienced an olfactory-triggered panic attack in the last month. Trauma associations and catastrophic cognitions (e.g. fears of a 'wind attack', 'weakness', and 'weak heart') were common during events of olfactory panic. Several case examples are presented. A multifactorial model of the generation of olfactory panic is adduced. The therapeutic implications of this model for the treatment of olfactory panic are discussed.

Intracranial pancreatic islet transplantation increases islet hormone expression in the rat brain and attenuates behavioral dysfunctions induced by MK-801 (dizocilpine).

PubMed

Bloch, Konstantin; Gil-Ad, Irit; Tarasenko, Igor; Vanichkin, Alexey; Taler, Michal; Hornfeld, Shay Henry; Vardi, Pnina; Weizman, Abraham

2015-06-01

The treatment of rodents with non-competitive antagonist of the N-Methyl-D-aspartate (NMDA) receptor, MK-801 (dizocilpine), induces symptoms of psychosis, deficits in spatial memory and impairment of synaptic plasticity. Recent studies have suggested that insulin administration might attenuate the cognitive dysfunctions through the modulatory effect on the expression of NMDA receptors and on the brain insulin signaling. Intrahepatic pancreatic islet transplantation is known as an efficient tool for correcting impaired insulin signaling. We examined the capacity of syngeneic islets grafted into the cranial subarachnoid cavity to attenuate behavioral dysfunctions in rats exposed to MK-801. Animals were examined in the open field (OF) and the Morris Water Maze (MWM) tests following acute or subchronic administration of MK-801. We found well-vascularized grafted islets expressing insulin, glucagon and somatostatin onto the olfactory bulb and prefrontal cortex. Significantly higher levels of insulin were detected in the hippocampus and prefrontal cortex of transplanted animals compared to the non-transplanted rats. All animals expressed normal peripheral glucose homeostasis for two months after transplantation. OF tests revealed that rats exposed to MK-801 treatment, showed hyper-responsiveness in motility parameters and augmented center field exploration compared to intact controls and these effects were attenuated by the grafted islets. Moreover, in the MWM, the rats treated with MK-801 showed impairment of spatial memory that were partially corrected by the grafted islets. In conclusion, intracranial islet transplantation leads to the expression of islet hormones in the brain and attenuates behavioral and cognitive dysfunctions in rats exposed to MK-801 administration without altering the peripheral glucose homeostasis. Copyright © 2015 Elsevier Inc. All rights reserved.

Ionotropic crustacean olfactory receptors.

PubMed

Corey, Elizabeth A; Bobkov, Yuriy; Ukhanov, Kirill; Ache, Barry W

2013-01-01

The nature of the olfactory receptor in crustaceans, a major group of arthropods, has remained elusive. We report that spiny lobsters, Panulirus argus, express ionotropic receptors (IRs), the insect chemosensory variants of ionotropic glutamate receptors. Unlike insects IRs, which are expressed in a specific subset of olfactory cells, two lobster IR subunits are expressed in most, if not all, lobster olfactory receptor neurons (ORNs), as confirmed by antibody labeling and in situ hybridization. Ligand-specific ORN responses visualized by calcium imaging are consistent with a restricted expression pattern found for other potential subunits, suggesting that cell-specific expression of uncommon IR subunits determines the ligand sensitivity of individual cells. IRs are the only type of olfactory receptor that we have detected in spiny lobster olfactory tissue, suggesting that they likely mediate olfactory signaling. Given long-standing evidence for G protein-mediated signaling in activation of lobster ORNs, this finding raises the interesting specter that IRs act in concert with second messenger-mediated signaling.

The Amelioration of Olfactory Acuity upon Sexual Maturation Might Affect Food Preferences

PubMed Central

Bignetti, Enrico; Sinesio, Fiorella; Aiello, Gaetano L.; Cannella, Carlo

2009-01-01

Upon sexual maturation, olfactory acuity in women ameliorates and starts oscillating across the cycle. During ovulation, mean olfactory threshold is 30 times lower than during bleeding. Interestingly, menstruated women undergo maleodorant trimethylaminuria. We argued that olfactory amelioration during ovulation might concur to a mating strategy, whereas olfactory impairment during bleeding might protect women against self-refusal. Testosterone and its 17β-estradiol derivative might be responsible for the synchronization of these menstrual events. Furthermore, we posed the question whether olfactory detection amelioration upon sexual maturation might provoke a change in food preferences, for instance a reduction in fish consumption. A preliminary survey in Italy provided encouraging results: 15-44 year-old women have lower fish consumption than 3-14 year-old girls. Surprisingly, men exhibited the same behaviour, so new olfactory tests as well as testosterone measurements are under way. PMID:22253964

High Fructose Diet inducing diabetes rapidly impacts olfactory epithelium and behavior in mice

PubMed Central

Rivière, Sébastien; Soubeyre, Vanessa; Jarriault, David; Molinas, Adrien; Léger-Charnay, Elise; Desmoulins, Lucie; Grebert, Denise; Meunier, Nicolas; Grosmaitre, Xavier

2016-01-01

Type 2 Diabetes (T2D), a major public health issue reaching worldwide epidemic, has been correlated with lower olfactory abilities in humans. As olfaction represents a major component of feeding behavior, its alteration may have drastic consequences on feeding behaviors that may in turn aggravates T2D. In order to decipher the impact of T2D on the olfactory epithelium, we fed mice with a high fructose diet (HFruD) inducing early diabetic state in 4 to 8 weeks. After only 4 weeks of this diet, mice exhibited a dramatic decrease in olfactory behavioral capacities. Consistently, this decline in olfactory behavior was correlated to decreased electrophysiological responses of olfactory neurons recorded as a population and individually. Our results demonstrate that, in rodents, olfaction is modified by HFruD-induced diabetes. Functional, anatomical and behavioral changes occurred in the olfactory system at a very early stage of the disease. PMID:27659313

Olfactory Fear Conditioning Induces Field Potential Potentiation in Rat Olfactory Cortex and Amygdala

ERIC Educational Resources Information Center

Messaoudi, Belkacem; Granjon, Lionel; Mouly, Anne-Marie; Sevelinges, Yannick; Gervais, Remi

2004-01-01

The widely used Pavlovian fear-conditioning paradigms used for studying the neurobiology of learning and memory have mainly used auditory cues as conditioned stimuli (CS). The present work assessed the neural network involved in olfactory fear conditioning, using olfactory bulb stimulation-induced field potential signal (EFP) as a marker of…

Luteinizing hormone-releasing hormone (LHRH) in rat olfactory systems.

PubMed

Witkin, J W; Silverman, A J

1983-08-20

The luteinizing hormone-releasing hormone (LHRH) systems of rat olfactory bulbs and nasal areas were studied in neonatal and adult rats. Animals were perfused with Zamboni's fixative and olfactory bulbs with nasal olfactory areas intact were removed, postfixed, and decalcified. LHRH was immunohistochemically demonstrated in unembedded frozen or vibratome sections. Luteinizing hormone-releasing hormone immunoreactive elements were found along the course of the nervus terminalis (NT) and within both the main and accessory olfactory bulbs (MOB and AOB, respectively). Both LHRH neurons and fibers were present in the AOB, but only fibers were detected in the MOB. The fibers of the AOB were not confined to any particular lamina while fibers in the MOB were found mainly in the external plexiform layer. LHRH fibers were found in the mucosa of the olfactory epithelium of the vomeronasal organ in both neonatal and adult rats. The NT probably serves as a source of LHRH fibers for both the AOB and the MOB and for fibers observed in the olfactory epithelium of the vomeronasal organ. Other likely sources of LHRH fibers in the olfactory bulb are discussed.

Effects of diversity in olfactory environment on children's sense of smell.

PubMed

Martinec Nováková, Lenka; Fialová, Jitka; Havlíček, Jan

2018-02-13

Diversity in children's everyday olfactory environment may affect the development of their olfactory abilities and odor awareness. To test this, we collected data on olfactory abilities using the Sniffin' Sticks and odor awareness with Children's Olfactory Behaviors in Everyday Life Questionnaire in 153 preschool children and retested them one and a half year later. Parents completed an inventory on children's exposure to a variety of odors and on their own odor awareness using the Odor Awareness Scale. We controlled for the effects of age and verbal fluency on the children's performance. We found that the children's odor identification and discrimination scores differed as a function of parental odor awareness. Although these effects were rather small, they were commensurate in size with those of gender and age. To the best of our knowledge, this study is the first to present evidence that diversity in children's olfactory environment affects variation in their olfactory abilities and odor awareness. We suggest that future studies consider the long-term impact of perceptual learning out of the laboratory and its consequences for olfactory development.

An evaluation of olfactory function in adults with gastro-esophageal reflux disease.

PubMed

Günbey, Emre; Gören, İbrahim; Ünal, Recep; Yılmaz, Melikşah

2016-01-01

To the best of the authors' knowledge, this study is the first to evaluate the olfactory function of adult patients diagnosed with GERD. The results revealed that adults with GERD have diminished olfactory function. This study aimed to evaluate the olfactory abilities of subjects using the 'Sniffin' Sticks' olfactory test. A total of 35 men and women aged 18-60 years with a diagnosis of GERD and 45 healthy controls were included in the study. The Sniffin' Sticks olfactory test results of the two groups were compared, and the relationship between the study findings and the olfactory parameters was evaluated. The odor threshold (10.1; 9.5, p = 0.016), odor identification (9.6; 8.1, p < 0.001), and odor discrimination (10.7; 8.9, p < 0.001) of the GERD group were significantly lower than those of the control group. A statistically significant positive correlation was detected between the accompanying chronic pharyngitis, chronic sinusitis, and odor parameters. A significant correlation was not detected between the laryngeal findings and the olfactory parameters.

Evaluation of olfactory function in adults with primary hypothyroidism.

PubMed

Günbey, Emre; Karlı, Rıfat; Gökosmanoğlu, Feyzi; Düzgün, Berkan; Ayhan, Emre; Atmaca, Hulusi; Ünal, Recep

2015-10-01

Sufficient clinical data are not available on the effect of hypothyroidism on olfactory function in adults. In this study, we aimed to evaluate the olfactory function of adult patients diagnosed with primary hypothyroidism. Forty-five patients aged between 18 and 60 years who were diagnosed with clinical primary hypothyroidism and 45 healthy controls who had normal thyroid function tests were included in the study. Sniffin' Sticks olfactory test results of the 2 groups were compared. The relationships between thyroid function tests and olfactory parameters were evaluated. Odor threshold, identification, and discrimination scores of the hypothyroid group were significantly lower than those of the control group (p < 0.001). A significant positive correlation was detected between free triiodothyronine (FT3) levels and odor threshold, identification, and discrimination scores (p < 0.001). There was no significant relationship between thyroid-stimulating hormone (TSH) or free thyroxine (FT4) levels and olfactory parameters. Our study revealed diminished olfactory function in adults with hypothyroidism. FT3 levels were found to have a more significant relationship with olfactory parameters than TSH or FT4 levels. © 2015 ARS-AAOA, LLC.

Gonadotropin-releasing hormone immunoreactivity in the adult and fetal human olfactory system.

PubMed

Kim, K H; Patel, L; Tobet, S A; King, J C; Rubin, B S; Stopa, E G

1999-05-01

Studies in fetal brain tissue of rodents, nonhuman primates and birds have demonstrated that cells containing gonadotropin-releasing hormone (GnRH) migrate from the olfactory placode across the nasal septum into the forebrain. The purpose of this study was to examine GnRH neurons in components of the adult and fetal human olfactory system. In the adult human brain (n=4), immunoreactive GnRH was evident within diffusely scattered cell bodies and processes in the olfactory bulb, olfactory nerve, olfactory cortex, and nervus terminalis located on the anterior surface of the gyrus rectus. GnRH-immunoreactive structures showed a similar distribution in 20-week human fetal brains (n=2), indicating that the migration of GnRH neurons is complete at this time. In 10-11-week fetal brains (n=2), more cells were noted in the nasal cavity than in the brain. Our data are consistent with observations made in other species, confirming olfactory derivation and migration of GnRH neurons into the brain from the olfactory placode. Copyright 1999 Elsevier Science B.V.

Olfactory function in psychotic disorders: Insights from neuroimaging studies

PubMed Central

Good, Kimberley P; Sullivan, Randii Lynn

2015-01-01

Olfactory deficits on measures of identification, familiarity, and memory are consistently noted in patients with psychotic disorders relative to age-matched controls. Olfactory intensity ratings, however, appear to remain intact while the data on hedonics and detection threshold are inconsistent. Despite the behavioral abnormalities noted, no specific regional brain hypoactivity has been identified in psychosis patients, for any of the olfactory domains. However, an intriguing finding emerged from this review in that the amygdala and pirifom cortices were not noted to be abnormal in hedonic processing (nor was the amygdala identified abnormal in any study) in psychotic disorders. This finding is in contrast to the literature in healthy individuals, in that this brain region is strongly implicated in olfactory processing (particularly for unpleasant odorants). Secondary olfactory cortex (orbitofrontal cortices, thalamus, and insula) was abnormally activated in the studies examined, particularly for hedonic processing. Further research, using consistent methodology, is required for better understanding the neurobiology of olfactory deficits. The authors suggest taking age and sex differences into consideration and further contrasting olfactory subgroups (impaired vs intact) to better our understanding of the heterogeneity of psychotic disorders. PMID:26110122

Mixture and odorant processing in the olfactory systems of insects: a comparative perspective.

PubMed

Clifford, Marie R; Riffell, Jeffrey A

2013-11-01

Natural olfactory stimuli are often complex mixtures of volatiles, of which the identities and ratios of constituents are important for odor-mediated behaviors. Despite this importance, the mechanism by which the olfactory system processes this complex information remains an area of active study. In this review, we describe recent progress in how odorants and mixtures are processed in the brain of insects. We use a comparative approach toward contrasting olfactory coding and the behavioral efficacy of mixtures in different insect species, and organize these topics around four sections: (1) Examples of the behavioral efficacy of odor mixtures and the olfactory environment; (2) mixture processing in the periphery; (3) mixture coding in the antennal lobe; and (4) evolutionary implications and adaptations for olfactory processing. We also include pertinent background information about the processing of individual odorants and comparative differences in wiring and anatomy, as these topics have been richly investigated and inform the processing of mixtures in the insect olfactory system. Finally, we describe exciting studies that have begun to elucidate the role of the processing of complex olfactory information in evolution and speciation.

The sense of smell, its signalling pathways, and the dichotomy of cilia and microvilli in olfactory sensory cells

PubMed Central

2007-01-01

Smell is often regarded as an ancillary perception in primates, who seem so dominated by their sense of vision. In this paper, we will portray some aspects of the significance of olfaction to human life and speculate on what evolutionary factors contribute to keeping it alive. We then outline the functional architecture of olfactory sensory neurons and their signal transduction pathways, which are the primary detectors that render olfactory perception possible. Throughout the phylogenetic tree, olfactory neurons, at their apical tip, are either decorated with cilia or with microvilli. The significance of this dichotomy is unknown. It is generally assumed that mammalian olfactory neurons are of the ciliary type only. The existance of so-called olfactory microvillar cells in mammals, however, is well documented, but their nature remains unclear and their function orphaned. This paper discusses the possibility, that in the main olfactory epithelium of mammals ciliated and microvillar sensory cells exist concurrently. We review evidence related to this hypothesis and ask, what function olfactory microvillar cells might have and what signalling mechanisms they use. PMID:17903277

Co-localization of TRPV2 and insulin-like growth factor-I receptor in olfactory neurons in adult and fetal mouse.

PubMed

Matsui, Hitoshi; Noguchi, Tomohiro; Takakusaki, Kaoru; Kashiwayanagi, Makoto

2014-01-01

TRPV2, a member of the transient receptor potential family, has been isolated as a capsaicin-receptor homolog and is thought to respond to noxious heat. Here we show that TRPV2 mRNA is predominantly expressed in the subpopulation of olfactory sensory neurons (OSNs). We carried out histochemical analyses of TRPV2 and insulin-like growth factor-I receptor (IGF-IR) using in situ hybridization and immunofluorescence in the adult olfactory system. In olfactory mucosa, intensive TRPV2 immunostaining was observed at the olfactory axon bundles but not at the soma. TRPV2-positive labeling was preferentially found in the olfactory nerve layer in the olfactory bulb (OB). Furthermore, we demonstrated that a positive signal for IGF-IR mRNA was detected in OSNs expressing TRPV2 mRNA. In embryonic stages, TRPV2 immunoreactivity was observed on axon bundles of developing OSNs in the nasal region starting from 12.5 d of gestation and through fetal development. Observations in this study suggest that TRPV2 coupled with IGF-IR localizes to growing olfactory axons in the OSNs.

The activity-dependent histone variant H2BE modulates the life span of olfactory neurons

PubMed Central

Santoro, Stephen W; Dulac, Catherine

2012-01-01

We have identified a replication-independent histone variant, Hist2h2be (referred to herein as H2be), which is expressed exclusively by olfactory chemosensory neurons. Levels of H2BE are heterogeneous among olfactory neurons, but stereotyped according to the identity of the co-expressed olfactory receptor (OR). Gain- and loss-of-function experiments demonstrate that changes in H2be expression affect olfactory function and OR representation in the adult olfactory epithelium. We show that H2BE expression is reduced by sensory activity and that it promotes neuronal cell death, such that inactive olfactory neurons display higher levels of the variant and shorter life spans. Post-translational modifications (PTMs) of H2BE differ from those of the canonical H2B, consistent with a role for H2BE in altering transcription. We propose a physiological function for H2be in modulating olfactory neuron population dynamics to adapt the OR repertoire to the environment. DOI: http://dx.doi.org/10.7554/eLife.00070.001 PMID:23240083

Olfactory imprinting is correlated with changes in gene expression in the olfactory epithelia of the zebrafish.

PubMed

Harden, Maegan V; Newton, Lucy A; Lloyd, Russell C; Whitlock, Kathleen E

2006-11-01

Odors experienced as juveniles can have significant effects on the behavior of mature organisms. A dramatic example of this occurs in salmon, where the odors experienced by developing fish determine the river to which they return as adults. Further examples of olfactory memories are found in many animals including vertebrates and invertebrates. Yet, the cellular and molecular bases underlying the formation of olfactory memory are poorly understood. We have devised a series of experiments to determine whether zebrafish can form olfactory memories much like those observed in salmonids. Here we show for the first time that zebrafish form and retain olfactory memories of an artificial odorant, phenylethyl alcohol (PEA), experienced as juveniles. Furthermore, we demonstrate that exposure to PEA results in changes in gene expression within the olfactory sensory system. These changes are evident by in situ hybridization in the olfactory epithelium of the developing zebrafish. Strikingly, our analysis by in situ hybridization demonstrates that the transcription factor, otx2, is up regulated in the olfactory sensory epithelia in response to PEA. This increase is evident at 2-3 days postfertilization and is maintained in the adult animals. We propose that the changes in otx2 gene expression are manifest as an increase in the number of neuronal precursors in the cells olfactory epithelium of the odor-exposed fish. Thus, our results reveal a role for the environment in controlling gene expression in the developing peripheral nervous system. Copyright 2006 Wiley Periodicals, Inc.

Effect of anatomy on human nasal air flow and odorant transport patterns: implications for olfaction.

PubMed

Zhao, Kai; Scherer, Peter W; Hajiloo, Shoreh A; Dalton, Pamela

2004-06-01

Recent studies that have compared CT or MRI images of an individual's nasal anatomy and measures of their olfactory sensitivity have found a correlation between specific anatomical areas and performance on olfactory assessments. Using computational fluid dynamics (CFD) techniques, we have developed a method to quickly (

Evolutionary Genomics of Genes Involved in Olfactory Behavior in the Drosophila melanogaster Species Group

PubMed Central

Lavagnino, Nicolás; Serra, François; Arbiza, Leonardo; Dopazo, Hernán; Hasson, Esteban

2012-01-01

Previous comparative genomic studies of genes involved in olfactory behavior in Drosophila focused only on particular gene families such as odorant receptor and/or odorant binding proteins. However, olfactory behavior has a complex genetic architecture that is orchestrated by many interacting genes. In this paper, we present a comparative genomic study of olfactory behavior in Drosophila including an extended set of genes known to affect olfactory behavior. We took advantage of the recent burst of whole genome sequences and the development of powerful statistical tools to analyze genomic data and test evolutionary and functional hypotheses of olfactory genes in the six species of the Drosophila melanogaster species group for which whole genome sequences are available. Our study reveals widespread purifying selection and limited incidence of positive selection on olfactory genes. We show that the pace of evolution of olfactory genes is mostly independent of the life cycle stage, and of the number of life cycle stages, in which they participate in olfaction. However, we detected a relationship between evolutionary rates and the position that the gene products occupy in the olfactory system, genes occupying central positions tend to be more constrained than peripheral genes. Finally, we demonstrate that specialization to one host does not seem to be associated with bursts of adaptive evolution in olfactory genes in D. sechellia and D. erecta, the two specialists species analyzed, but rather different lineages have idiosyncratic evolutionary histories in which both historical and ecological factors have been involved. PMID:22346339

Olfactory short-term memory encoding and maintenance - an event-related potential study.

PubMed

Lenk, Steffen; Bluschke, Annet; Beste, Christian; Iannilli, Emilia; Rößner, Veit; Hummel, Thomas; Bender, Stephan

2014-09-01

This study examined whether the memory encoding and short term maintenance of olfactory stimuli is associated with neurophysiological activation patterns which parallel those described for sensory modalities such as vision and auditory. We examined olfactory event-related potentials in an olfactory change detection task in twenty-four healthy adults and compared the measured activation to that found during passive olfactory stimulation. During the early olfactory post-processing phase, we found a sustained negativity over bilateral frontotemporal areas in the passive perception condition which was enhanced in the active memory task. There was no significant lateralization in either experimental condition. During the maintenance interval at the end of the delay period, we still found sustained activation over bilateral frontotemporal areas which was more negative in trials with correct - as compared to incorrect - behavioural responses. This was complemented by a general significantly stronger frontocentral activation. Summarizing, we were able to show that olfactory short term memory involves a parallel sequence of activation as found in other sensory modalities. In addition to olfactory-specific frontotemporal activations in the memory encoding phase, we found slow cortical potentials over frontocentral areas during the memory maintenance phase indicating the activation of a supramodal memory maintenance system. These findings could represent the neurophysiological underpinning of the 'olfactory flacon', the olfactory counter-part to the visual sketchpad and phonological loop embedded in Baddeley's working memory model. Copyright © 2014 Elsevier Inc. All rights reserved.

[Organization of olfactory system of the Indian major carp Labeo rohita (Ham.): a study using scanning and transmission microscopy].

PubMed

Bhute, Y V; Baile, V V

2007-01-01

Catla catla, Labeo rohita, and Cirrhinus mrigala are important alimentary fish in India. Their reproduction (breeding) depends on season. The fish perceive external factors-stimuli and chemical signals through the olfactory system that plays the key role in the central regulation of reproduction. However, in the available literature, any electron microscopy data on organization of olfactory elements in these fish are absent. We have studied ultrastructure of the olfactory organ in male L. rohita by using scanning (SEM) and transmission electron microscopy (TEM). The olfactory organ consists of olfactory epithelium, a short nerve, and olfactory bulb. The organ has oval shape and consists of approximately 47-52 lamellae in adult fish and of 14-20 lamellae in fish at the stage of fingerling. These lamellae originate from the midline raphe. By using SEM, the presence of microvillar sensory and ciliated non-sensory cells in these lamellae is shown. By using TEM, a microvillar receptor cell is revealed, which has rough endoplasmic reticulum and Golgi apparatus towards the apical end. Basal cells are found at the base of the receptor cell; supporting cells are located adjacent to olfactory receptor neurons, while epithelial cells--in the non-sensory part of olfactory epithelium. Mast, blastema and macrophages cells are also found in the basal lamina. This work is the first publication on structural organization of olfactory system of the Indian major carp, which provides information about morphological and ultrastructural organization of olfactory system and opens new opportunities for study of chemical neuroanatomy, sensory signal processing, and nervous regulation of reproduction of the Indian major carp.

Hypothalamus-Olfactory System Crosstalk: Orexin A Immunostaining in Mice

PubMed Central

Gascuel, Jean; Lemoine, Aleth; Rigault, Caroline; Datiche, Frédérique; Benani, Alexandre; Penicaud, Luc; Lopez-Mascaraque, Laura

2012-01-01

It is well known that olfaction influences food intake, and conversely, that an individual’s nutritional status modulates olfactory sensitivity. However, what is still poorly understood is the neuronal correlate of this relationship, as well as the connections between the olfactory bulb and the hypothalamus. The goal of this report is to analyze the relationship between the olfactory bulb and hypothalamus, focusing on orexin A immunostaining, a hypothalamic neuropeptide that is thought to play a role in states of sleep/wakefulness. Interestingly, orexin A has also been described as a food intake stimulator. Such an effect may be due in part to the stimulation of the olfactory bulbar pathway. In rats, orexin positive cells are concentrated strictly in the lateral hypothalamus, while their projections invade nearly the entire brain including the olfactory system. Therefore, orexin appears to be a good candidate to play a pivotal role in connecting olfactory and hypothalamic pathways. So far, orexin has been described in rats, however, there is still a lack of information concerning its expression in the brains of adult and developing mice. In this context, we revisited the orexin A pattern in adult and developing mice using immunohistological methods and confocal microscopy. Besides minor differences, orexin A immunostaining in mice shares many features with those observed in rats. In the olfactory bulb, even though there are few orexin projections, they reach all the different layers of the olfactory bulb. In contrast to the presence of orexin projections in the main olfactory bulb, almost none have been found in the accessory olfactory bulb. The developmental expression of orexin A supports the hypothesis that orexin expression only appears post-natally. PMID:23162437

Neuropeptide Y in the olfactory system, forebrain and pituitary of the teleost, Clarias batrachus.

PubMed

Gaikwad, Archana; Biju, K C; Saha, Subhash G; Subhedar, Nishikant

2004-03-01

Distribution of neuropeptide Y (NPY)-like immunoreactivity in the forebrain of catfish Clarias batrachus was examined with immunocytochemistry. Conspicuous immunoreactivity was seen in the olfactory receptor neurons (ORNs), their projections in the olfactory nerve, fascicles of the olfactory nerve layer in the periphery of bulb and in the medial olfactory tracts as they extend to the telencephalic lobes. Ablation of the olfactory organ resulted in loss of immunoreactivity in the olfactory nerve layer of the bulb and also in the fascicles of the medial olfactory tracts. This evidence suggests that NPY may serve as a neurotransmitter in the ORNs and convey chemosensory information to the olfactory bulb, and also to the telencephalon over the extrabulbar projections. In addition, network of beaded immunoreactive fibers was noticed throughout the olfactory bulb, which did not respond to ablation experiment. These fibers may represent centrifugal innervation of the bulb. Strong immunoreactivity was encountered in some ganglion cells of nervus terminalis. Immunoreactive fibers and terminal fields were widely distributed in the telencephalon. Several neurons of nucleus entopeduncularis were moderately immunoreactive; and a small population of neurons in nucleus preopticus periventricularis was also labeled. Immunoreactive terminal fields were particularly conspicuous in the preoptic, the tuberal areas, and the periventricular zone around the third ventricle and inferior lobes. NPY immunoreactive cells and fibers were detected in all the lobes of the pituitary gland. Present results describing the localization of NPY in the forebrain of C. batrachus are in concurrence with the pattern of the immunoreactivity encountered in other teleosts. However, NPY in olfactory system of C. batrachus is a novel feature that suggests a role for the peptide in processing of chemosensory information.

Bilateral Olfactory Mucosa Damage Induces the Disappearance of Olfactory Glomerulus and Reduces the Expression of Extrasynaptic α5GABAARs in the Hippocampus in Early Postnatal Sprague Dawley Rats.

PubMed

Zheng, Xiaomin; Liang, Liang; Hei, Changchun; Yang, Wenjuan; Zhang, Tingyuan; Wu, Kai; Qin, Yi; Chang, Qing

2018-04-17

Chloroform-induced olfactory mucosal degeneration has been reported in adult rats following gavage. We used fixed-point chloroform infusions on different postnatal days (PNDs) to investigate the effects of early olfactory bilateral deprivation on the main olfactory bulbs in Sprague Dawley rats. The experimental groups included rats infused with chloroform (5 μl) or saline (sham, 5 μl) on PNDs 3 and 8, and rats not receiving infusions (control) (n = 6 in all groups). Rats receiving chloroform on PND 3 showed significant hypoevolutism when compared to those in other groups (P < 0.05). There was a complete disappearance and a significant reduction in the size of olfactory glomeruli in the PND 3 and 8 groups, respectively, when compared to the respective sham groups. Rats receiving chloroform on PND 3 had significant memory impairment (P < 0.01) and increased levels of learned helplessness (P < 0.05), as measured using the Morris water maze and tail suspension tests, respectively. GABA A receptor alpha5 subunit (α5GABA A R) expression in hippocampal neurons was significantly lower in rats receiving chloroform on PND 3 than in rats in other groups (P < 0.01), as measured using immunohistochemistry and polymerase chain reaction. There was thus a critical period for the preservation of regenerative ability in olfactory receptor neurons, during which damage and olfactory deprivation led to altered rhinencephalon structure and disappearance of olfactory glomeruli, which induced hypoevolutism. Olfactory deprivation after the critical period had no significant effect on olfactory receptor neuron regeneration, leading to reduced developmental and behavioral effects in Sprague Dawley rats.

Qualitative data analysis for an exploratory sensory study of Grechetto wine.

PubMed

Esti, Marco; González Airola, Ricardo L; Moneta, Elisabetta; Paperaio, Marina; Sinesio, Fiorella

2010-02-15

Grechetto is a traditional white-grape vine, widespread in Umbria and Lazio regions in central Italy. Despite the wine commercial diffusion, little literature on its sensory characteristics is available. The present study is an exploratory research conducted with the aim of identifying the sensory markers of Grechetto wine and of evaluating the effect of clone, geographical area, vintage and producer on sensory attributes. A qualitative sensory study was conducted on 16 wines, differing for vintage, Typical Geographic Indication, and clone, collected from 7 wineries, using a trained panel in isolation who referred to a glossary of 133 white wine descriptors. Sixty-five attributes identified by a minimum of 50% of the respondents were submitted to a correspondence analysis to link wine samples to the sensory attributes. Seventeen terms identified as common to all samples are considered as characteristics of Grechetto wine, 10 of which olfactory: fruity, apple, acacia flower, pineapple, banana, floral, herbaceous, honey, apricot and peach. In order to interpret the relationship between design variables and sensory attributes data on 2005 and 2006 wines, the 28 most discriminating descriptors were projected in a principal component analysis. The first principal component was best described by olfactory terms and the second by gustative attributes. Good reproducibility of results was obtained for the two vintages. For one winery, vintage effect (2002-2006) was described in a new principal component analysis model applied on 39 most discriminating descriptors, which globally explained about 84% of the variance. In the young wines the notes of sulphur, yeast, dried fruit, butter, combined with herbaceous fresh and tropical fruity notes (melon, grapefruit) were dominant. During wine aging, sweeter notes, like honey, caramel, jam, become more dominant as well as some mineral notes, such as tuff and flint. Copyright 2009 Elsevier B.V. All rights reserved.

Detecting contaminant-induced apoptosis and necrosis in lake trout thymocytes via flow cytometry.

USGS Publications Warehouse

Sweet, Leonard I.; Passino-Reader, Dora R.; Meier, Peter G.; Omann, Geneva M.; Stolen, J.S.; Fletcher, T.C.; Rowley, A.F.; Zelikoff, J.T.; Kaattari, S.L.; Smith, S.A.

1997-01-01

This chapter details the cytofluorometric techniques employed to assess levels of active (apoptosis) and passive (necrotic) cell death in untreated and contaminant-treated fish thymocytes. The thymus is believed to be a central component of hematopoiesis and immune function in teleosts (Abelli et al., 1996). Hence, chemically-elicited adverse effects to the thymus may result in immunomodulation and organ dysfunction. However, it is not well documented that environmental contaminants induce apoptosis, or programmed cell death. There is some evidence suggesting that low level exposure to waterborne contaminants can specifically induce cell death in the olfactory epithelium of rainbow trout (Julliard et al., 1996). Presently, only limited information is available in the literature regarding apoptotic death in piscine immune cells (Alford et al., 1994; Greenlee et al., 1991).

Reorganization of neuronal circuits of the central olfactory system during postprandial sleep

PubMed Central

Yamaguchi, Masahiro; Manabe, Hiroyuki; Murata, Koshi; Mori, Kensaku

2013-01-01

Plastic changes in neuronal circuits often occur in association with specific behavioral states. In this review, we focus on an emerging view that neuronal circuits in the olfactory system are reorganized along the wake-sleep cycle. Olfaction is crucial to sustaining the animals' life, and odor-guided behaviors have to be newly acquired or updated to successfully cope with a changing odor world. It is therefore likely that neuronal circuits in the olfactory system are highly plastic and undergo repeated reorganization in daily life. A remarkably plastic feature of the olfactory system is that newly generated neurons are continually integrated into neuronal circuits of the olfactory bulb (OB) throughout life. New neurons in the OB undergo an extensive selection process, during which many are eliminated by apoptosis for the fine tuning of neuronal circuits. The life and death decision of new neurons occurs extensively during a short time window of sleep after food consumption (postprandial sleep), a typical daily olfactory behavior. We review recent studies that explain how olfactory information is transferred between the OB and the olfactory cortex (OC) along the course of the wake-sleep cycle. Olfactory sensory input is effectively transferred from the OB to the OC during waking, while synchronized top-down inputs from the OC to the OB are promoted during the slow-wave sleep. We discuss possible neuronal circuit mechanisms for the selection of new neurons in the OB, which involves the encoding of olfactory sensory inputs and memory trace formation during waking and internally generated activities in the OC and OB during subsequent sleep. The plastic changes in the OB and OC are well coordinated along the course of olfactory behavior during wakefulness and postbehavioral rest and sleep. We therefore propose that the olfactory system provides an excellent model in which to understand behavioral state-dependent plastic mechanisms of the neuronal circuits in the brain. PMID:23966911

Hereditary sensory and autonomic neuropathy type IID caused by an SCN9A mutation.

PubMed

Yuan, Junhui; Matsuura, Eiji; Higuchi, Yujiro; Hashiguchi, Akihiro; Nakamura, Tomonori; Nozuma, Satoshi; Sakiyama, Yusuke; Yoshimura, Akiko; Izumo, Shuji; Takashima, Hiroshi

2013-04-30

To identify the clinical features of Japanese patients with suspected hereditary sensory and autonomic neuropathy (HSAN) on the basis of genetic diagnoses. On the basis of clinical, in vivo electrophysiologic, and pathologic findings, 9 Japanese patients with sensory and autonomic nervous dysfunctions were selected. Eleven known HSAN disease-causing genes and 5 related genes were screened using a next-generation sequencer. A homozygous mutation, c.3993delGinsTT, was identified in exon 22 of SCN9A from 2 patients/families. The clinical phenotype was characterized by adolescent or congenital onset with loss of pain and temperature sensation, autonomic nervous dysfunctions, hearing loss, and hyposmia. Subsequently, this mutation was discovered in one of patient 1's sisters, who also exhibited sensory and autonomic nervous system dysfunctions, with recurrent fractures being the most predominant feature. Nerve conduction studies revealed definite asymmetric sensory nerve involvement in patient 1. In addition, sural nerve pathologic findings showed loss of large myelinated fibers in patient 1, whereas the younger patient showed normal sural nerve pathology. We identified a novel homozygous mutation in SCN9A from 2 Japanese families with autosomal recessive HSAN. This loss-of-function SCN9A mutation results in disturbances in the sensory, olfactory, and autonomic nervous systems. We propose that SCN9A mutation results in the new entity of HSAN type IID, with additional symptoms including hyposmia, hearing loss, bone dysplasia, and hypogeusia.

Olfactory-Triggered Panic Attacks Among Khmer Refugees: A Contextual Approach

PubMed Central

Hinton, Devon; Pich, Vuth; Chhean, Dara; Pollack, Mark

2009-01-01

One hundred Khmer refugees attending a psychiatric clinic were surveyed to determine the prevalence of olfactory-triggered panic attacks as well as certain characteristics of the episodes, including trigger (i.e. type of odor), frequency, length, somatic symptoms, and the rate of associated flashbacks and catastrophic cognitions. Forty-five of the 100 patients had experienced an olfactory-triggered panic attack in the last month. Trauma associations and catastrophic cognitions (e.g. fears of a ‘wind attack,’ ‘weakness,’ and ‘weak heart’) were common during events of olfactory panic. Several case examples are presented. A multifactorial model of the generation of olfactory panic is adduced. The therapeutic implications of this model for the treatment of olfactory panic are discussed. PMID:15446720

Smelling time: a neural basis for olfactory scene analysis

PubMed Central

Ache, Barry W.; Hein, Andrew M.; Bobkov, Yuriy V.; Principe, Jose C.

2016-01-01

Behavioral evidence from phylogenetically diverse animals and humans suggests that olfaction could be much more involved in interpreting space and time than heretofore imagined by extracting temporal information inherent in the olfactory signal. If this is the case, the olfactory system must have neural mechanisms capable of encoding time at intervals relevant to the turbulent odor world in which many animals live. We review evidence that animals can use populations of rhythmically active or ‘bursting’ olfactory receptor neurons (bORNs) to extract and encode temporal information inherent in natural olfactory signals. We postulate that bORNs represent an unsuspected neural mechanism through which time can be accurately measured, and that ‘smelling time’ completes the requirements for true olfactory scene analysis. PMID:27594700

Olfactory deposition of inhaled nanoparticles in humans

PubMed Central

Garcia, Guilherme J. M.; Schroeter, Jeffry D.; Kimbell, Julia S.

2016-01-01

Context Inhaled nanoparticles can migrate to the brain via the olfactory bulb, as demonstrated in experiments in several animal species. This route of exposure may be the mechanism behind the correlation between air pollution and human neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. Objectives This manuscript aims to (1) estimate the dose of inhaled nanoparticles that deposit in the human olfactory epithelium during nasal breathing at rest and (2) compare the olfactory dose in humans with our earlier dose estimates for rats. Materials and methods An anatomically-accurate model of the human nasal cavity was developed based on computed tomography scans. The deposition of 1–100 nm particles in the whole nasal cavity and its olfactory region were estimated via computational fluid dynamics (CFD) simulations. Our CFD methods were validated by comparing our numerical predictions for whole-nose deposition with experimental data and previous CFD studies in the literature. Results In humans, olfactory dose of inhaled nanoparticles is highest for 1–2 nm particles with approximately 1% of inhaled particles depositing in the olfactory region. As particle size grows to 100 nm, olfactory deposition decreases to 0.01% of inhaled particles. Discussion and conclusion Our results suggest that the percentage of inhaled particles that deposit in the olfactory region is lower in humans than in rats. However, olfactory dose per unit surface area is estimated to be higher in humans due to their larger minute volume. These dose estimates are important for risk assessment and dose-response studies investigating the neurotoxicity of inhaled nanoparticles. PMID:26194036

Adiponectin Enhances the Responsiveness of the Olfactory System

PubMed Central

Loch, Diana; Heidel, Christian; Breer, Heinz; Strotmann, Jörg

2013-01-01

The peptide hormone adiponectin is secreted by adipose tissue and the circulating concentration is reversely correlated with body fat mass; it is considered as starvation signal. The observation that mature sensory neurons of the main olfactory epithelium express the adiponectin receptor 1 has led to the concept that adiponectin may affect the responsiveness of the olfactory system. In fact, electroolfactogram recordings from olfactory epithelium incubated with exogenous adiponectin resulted in large amplitudes upon odor stimulation. To determine whether the responsiveness of the olfactory sensory neurons was enhanced, we have monitored the odorant-induced expression of the immediate early gene Egr1. It was found that in an olfactory epithelium incubated with nasally applied adiponectin the number of Egr1 positive cells was significantly higher compared to controls, suggesting that adiponectin rendered the olfactory neurons more responsive to an odorant stimulus. To analyze whether the augmented responsiveness of sensory neurons was strong enough to elicit a higher neuronal activity in the olfactory bulb, the number of activated periglomerular cells of a distinct glomerulus was determined by monitoring the stimulus-induced expression of c-fos. The studies were performed using the transgenic mOR256-17-IRES-tauGFP mice which allowed to visualize the corresponding glomerulus and to stimulate with a known ligand. The data indicate that upon exposure to 2,3-hexanedione in adiponectin-treated mice the number of activated periglomerular neurons was significantly increased compared to controls. The results of this study indicate that adiponectin increases the responsiveness of the olfactory system, probably due to a higher responsiveness of olfactory sensory neurons. PMID:24130737

Diagnosis and clinical characteristics of congenital anosmia: case series report.

PubMed

Qu, Qiuyi; Liu, Jianfeng; Ni, Daofeng; Zhang, Qiuhang; Yang, Dazhang; Wang, Naya; Wu, Xueyan; Han, Honglei

2010-12-01

congenital anosmia is extremely rare and tends to present late. We report on a series of patients with congenital anosmia to analyze its clinical characteristics and present illustrative cases. retrospective chart review. tertiary care centre. thirty-five patients with congenital anosmia were reviewed. A thorough medical history taking, physical examination, and nasal endoscopy were performed in all patients. T&T olfactory testing (n = 33), olfactory event-related potentials (OERPs) (n = 33), and sinonasal computed tomography (CT) (n = 35) were carried out. Magnetic resonance images (MRIs) of the olfactory pathway (n = 34) were available. Serum sex hormones were tested (n = 33). physical examination, olfactory testing, MRI of the olfactory pathway, and serum sex hormones. twenty cases were isolated congenital anosmia (ICA). Fifteen cases were congenital anosmia with other anomalies, including 12 cases with Kallmann syndrome (KS), two with CHARGE syndrome, and one with hypoplasia of the nasal cavity and nasal sinus. T&T olfactory testing indicated anosmia (n = 33). No OERP was obtained (n = 33). CT scans indicated three abnormal patients, including two with unilateral choanal atresia and one with hypoplasia of the nasal cavity and sinus. MRI demonstrated aplasia or hypoplasia of the olfactory bulbs, tracts, and olfactory sulci (n = 34). Serum sex hormones were low in 12 patients with KS. early diagnosis of congenital anosmia on the basis of olfactory symptoms is difficult. MRI of the olfactory pathway plays an important role in anatomic location. ICA is the most common congenital anosmia. KS is the primary presentation of congenital anosmia with other anomalies.

The cyclic nucleotide gated channel subunit CNG-1 instructs behavioral outputs in Caenorhabditis elegans by coincidence detection of nutritional status and olfactory input.

PubMed

He, Chao; Altshuler-Keylin, Svetlana; Daniel, David; L'Etoile, Noelle D; O'Halloran, Damien

2016-10-06

In mammals, olfactory subsystems have been shown to express seven-transmembrane G-protein-coupled receptors (GPCRs) in a one-receptor-one-neuron pattern, whereas in Caenorhabditis elegans, olfactory sensory neurons express multiple G-protein coupled odorant receptors per olfactory sensory neuron. In both mammalian and C. elegans olfactory sensory neurons (OSNs), the process of olfactory adaptation begins within the OSN; this process of negative feedback within the mammalian OSN has been well described in mammals and enables activated OSNs to desensitize their response cell autonomously while attending to odors detected by separate OSNs. However, the mechanism that enables C. elegans to adapt to one odor and attend to another odor sensed by the same olfactory sensory neuron remains unclear. We found that the cyclic nucleotide gated channel subunit CNG-1 is required to promote cross adaptation responses between distinct olfactory cues. This change in sensitivity to a pair of odorants after persistent stimulation by just one of these odors is modulated by the internal nutritional state of the animal, and we find that this response is maintained across a diverse range of food sources for C. elegans. We also reveal that CNG-1 integrates food related cues for exploratory motor output, revealing that CNG-1 functions in multiple capacities to link nutritional information with behavioral output. Our data describes a novel model whereby CNG channels can integrate the coincidence detection of appetitive and olfactory information to set olfactory preferences and instruct behavioral outputs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Prevalence of olfactory impairment in older adults.

PubMed

Murphy, Claire; Schubert, Carla R; Cruickshanks, Karen J; Klein, Barbara E K; Klein, Ronald; Nondahl, David M

2002-11-13

Older adults represent the fastest-growing segment of the US population, and prevalences of vision and hearing impairment have been extensively evaluated. However, despite the importance of sense of smell for nutrition and safety, the prevalence of olfactory impairment in older US adults has not been studied. To determine the prevalence of olfactory impairment in older adults. A total of 2491 Beaver Dam, Wis, residents aged 53 to 97 years participating in the 5-year follow-up examination (1998-2000) for the Epidemiology of Hearing Loss Study, a population-based, cross-sectional study. Olfactory impairment, assessed by the San Diego Odor Identification Test and self-report. The mean (SD) prevalence of impaired olfaction was 24.5% (1.7%). The prevalence increased with age; 62.5% (95% confidence interval [CI], 57.4%-67.7%) of 80- to 97-year-olds had olfactory impairment. Olfactory impairment was more prevalent among men (adjusted prevalence ratio, 1.92; 95% CI, 1.65-2.19). Current smoking, stroke, epilepsy, and nasal congestion or upper respiratory tract infection were also associated with increased prevalence of olfactory impairment. Self-reported olfactory impairment was low (9.5%) and this measure became less accurate with age. In the oldest group, aged 80 to 97 years, sensitivity of self-report was 12% for women and 18% for men. This study demonstrates that prevalence of olfactory impairment among older adults is high and increases with age. Self-report significantly underestimated prevalence rates obtained by olfaction testing. Physicians and caregivers should be particularly alert to the potential for olfactory impairment in the elderly population.

Beta and gamma oscillatory activities associated with olfactory memory tasks: different rhythms for different functional networks?

PubMed Central

Martin, Claire; Ravel, Nadine

2014-01-01

Olfactory processing in behaving animals, even at early stages, is inextricable from top down influences associated with odor perception. The anatomy of the olfactory network (olfactory bulb, piriform, and entorhinal cortices) and its unique direct access to the limbic system makes it particularly attractive to study how sensory processing could be modulated by learning and memory. Moreover, olfactory structures have been early reported to exhibit oscillatory population activities easy to capture through local field potential recordings. An attractive hypothesis is that neuronal oscillations would serve to “bind” distant structures to reach a unified and coherent perception. In relation to this hypothesis, we will assess the functional relevance of different types of oscillatory activity observed in the olfactory system of behaving animals. This review will focus primarily on two types of oscillatory activities: beta (15–40 Hz) and gamma (60–100 Hz). While gamma oscillations are dominant in the olfactory system in the absence of odorant, both beta and gamma rhythms have been reported to be modulated depending on the nature of the olfactory task. Studies from the authors of the present review and other groups brought evidence for a link between these oscillations and behavioral changes induced by olfactory learning. However, differences in studies led to divergent interpretations concerning the respective role of these oscillations in olfactory processing. Based on a critical reexamination of those data, we propose hypotheses on the functional involvement of beta and gamma oscillations for odor perception and memory. PMID:25002840

Changes in the serotonergic system in the main olfactory bulb of rats unilaterally deprived from birth to adulthood.

PubMed

Gómez, C; Briñón, J G; Orio, L; Colado, M I; Lawrence, A J; Zhou, F C; Vidal, M; Barbado, M V; Alonso, J R

2007-02-01

The serotonergic system plays a key role in the modulation of olfactory processing. The present study examined the plastic response of this centrifugal system after unilateral naris occlusion, analysing both serotonergic afferents and receptors in the main olfactory bulb. After 60 days of sensory deprivation, the serotonergic system exhibited adaptive changes. Olfactory deprivation caused a general increase in the number of fibres immunopositive for serotonin but not of those immunopositive for the serotonin transporter. HPLC data revealed an increase in serotonin levels but not in those of its major metabolite, 5-hydroxyindole acetic acid, resulting in a decrease in the 5-hydroxyindole acetic acid/serotonin ratio. These changes were observed not only in the deprived but also in the contralateral olfactory bulb. Double serotonin-tyrosine hydroxylase immunolabelling revealed that the glomerular regions of the deprived olfactory bulb with a high serotonergic fibre density showed a strong reduction in tyrosine hydroxylase. Finally, the serotonin(2A) receptor distribution density and the number of juxtaglomerular cells immunopositive for serotonin(2A) receptor remained unaltered after olfactory deprivation. Environmental stimulation modulated the serotonergic afferents to the olfactory bulb. Our results indicate the presence of a bilateral accumulation of serotonin in the serotonergic axon network, with no changes in serotonin(2A) receptor density after unilateral olfactory deprivation.

Expression of calmodulin mRNA in rat olfactory neuroepithelium.

PubMed

Biffo, S; Goren, T; Khew-Goodall, Y S; Miara, J; Margolis, F L

1991-04-01

A calmodulin (CaM) cDNA was isolated by differential hybridization screening of a lambda gt10 library prepared from rat olfactory mucosa. This cDNA fragment, containing most of the open reading frame of the rat CaMI gene, was subcloned and used to characterize steady-state expression of CaM mRNA in rat olfactory neuroepithelium and bulb. Within the bulb mitral cells are the primary neuronal population expressing CaM mRNA. The major CaM mRNA expressed in the olfactory mucosa is 1.7 kb with smaller contributions from mRNAs of 4.0 and 1.4 kb. CaM mRNA was primarily associated with the olfactory neurons and, despite the cellular complexity of the tissue and the known involvement of CaM in diverse cellular processes, was only minimally evident in sustentacular cells, gland cells or respiratory epithelium. Following bulbectomy CaM mRNA declines in the olfactory neuroepithelium as does olfactory marker protein (OMP) mRNA. In contrast to the latter, CaM mRNA makes a partial recovery by one month after surgery. These results, coupled with those from in situ hybridization, indicate that CaM mRNA is expressed in both mature and immature olfactory neurons. The program regulating CaM gene expression in olfactory neurons is distinct from those controlling expression of B50/GAP43 in immature, or OMP in mature, neurons respectively.

Histological properties of the nasal cavity and olfactory bulb of the Japanese jungle crow Corvus macrorhynchos.

PubMed

Yokosuka, Makoto; Hagiwara, Akiko; Saito, Toru R; Tsukahara, Naoki; Aoyama, Masato; Wakabayashi, Yoshihiro; Sugita, Shoei; Ichikawa, Masumi

2009-09-01

The nasal cavity and olfactory bulb (OB) of the Japanese jungle crow (Corvus macrorhynchos) were studied using computed tomography (CT) and histochemical staining. The nasal septum divided the nasal cavity in half. The anterior and maxillary conchae were present on both sides of the nasal cavity, but the posterior concha was indistinct. A small OB was present on the ventral surface of the periphery of the cerebrum. The OB-brain ratio--the ratio of the size of the OB to that of the cerebral hemisphere--was 6.13. The olfactory nerve bundles projected independently to the OB, which appeared fused on gross examination. Histochemical analysis confirmed the fusion of all OB layers. Using a neural tracer, we found that the olfactory nerve bundles independently projected to the olfactory nerve layer (ONL) and glomerular layer (GL) of the left and right halves of the fused OB. Only 4 of 21 lectins bound to the ONL and GL. Thus, compared with mammals and other birds, the jungle crow may have a poorly developed olfactory system and an inferior sense of olfaction. However, it has been contended recently that the olfactory abilities of birds cannot be judged from anatomical findings alone. Our results indicate that the olfactory system of the jungle crow is an interesting research model to evaluate the development and functions of vertebrate olfactory systems.

"Disability Means, um, Dysfunctioning People": A Qualitative Analysis of the Meaning and Experience of Disability among Adults with Intellectual Disabilities

ERIC Educational Resources Information Center

Monteleone, Rebecca; Forrester-Jones, Rachel

2017-01-01

Background: There has been little qualitative analysis of the experience of stigma, social comparisons and conception of identity among adults with intellectual disabilities (ID). This study aimed to develop an understanding of how adults with intellectual disabilities experience their own disability, and any implications relating to self-esteem,…

Differences in peripheral sensory input to the olfactory bulb between male and female mice

NASA Astrophysics Data System (ADS)

Kass, Marley D.; Czarnecki, Lindsey A.; Moberly, Andrew H.; McGann, John P.

2017-04-01

Female mammals generally have a superior sense of smell than males, but the biological basis of this difference is unknown. Here, we demonstrate sexually dimorphic neural coding of odorants by olfactory sensory neurons (OSNs), primary sensory neurons that physically contact odor molecules in the nose and provide the initial sensory input to the brain’s olfactory bulb. We performed in vivo optical neurophysiology to visualize odorant-evoked OSN synaptic output into olfactory bub glomeruli in unmanipulated (gonad-intact) adult mice from both sexes, and found that in females odorant presentation evoked more rapid OSN signaling over a broader range of OSNs than in males. These spatiotemporal differences enhanced the contrast between the neural representations of chemically related odorants in females compared to males during stimulus presentation. Removing circulating sex hormones makes these signals slower and less discriminable in females, while in males they become faster and more discriminable, suggesting opposite roles for gonadal hormones in influencing male and female olfactory function. These results demonstrate that the famous sex difference in olfactory abilities likely originates in the primary sensory neurons, and suggest that hormonal modulation of the peripheral olfactory system could underlie differences in how males and females experience the olfactory world.

Expression of corticosteroid binding globulin in the rat olfactory system.

PubMed

Dölz, Wilfried; Eitner, Annett; Caldwell, Jack D; Jirikowski, Gustav F

2013-05-01

Glucocorticoids are known to act on the olfactory system although their mode of action is still unclear since nuclear glucocorticoid receptors are mostly absent in the olfactory mucosa. In this study we used immunocytochemistry, in situ hybridization, and RT-PCR to study the expression and distribution of corticosteroid binding globulin (CBG) in the rat olfactory system. Mucosal goblet cells could be immunostained for CBG. Nasal secretion contained measurable amounts of CBG suggesting that CBG is liberated. CBG immunoreactivity was localized in many of the basal cells of the olfactory mucosa, while mature sensory cells contained CBG only in processes as determined by double immunostaining with the olfactory marker protein OMP. This staining was most pronounced in the vomeronasal organ (VNO). The appearance of CBG in the non-sensory and sensory parts of the VNO and in nerve terminals in the accessory bulb indicated axonal transport. Portions of the periglomerular cells, the mitral cells and the tufted cells were also CBG positive. CBG encoding transcripts were confirmed by RT-PCR in homogenates of the olfactory mucosa and VNO. Olfactory CBG may be significant for uptake, accumulation and transport of glucocorticoids, including aerosolic cortisol. Copyright © 2012 Elsevier GmbH. All rights reserved.

Odorant-Dependent Generation of Nitric Oxide in Mammalian Olfactory Sensory Neurons

PubMed Central

Brunert, Daniela; Kurtenbach, Stefan; Isik, Sonnur; Benecke, Heike; Gisselmann, Günter; Schuhmann, Wolfgang; Hatt, Hanns; Wetzel, Christian H.

2009-01-01

The gaseous signalling molecule nitric oxide (NO) is involved in various physiological processes including regulation of blood pressure, immunocytotoxicity and neurotransmission. In the mammalian olfactory bulb (OB), NO plays a role in the formation of olfactory memory evoked by pheromones as well as conventional odorants. While NO generated by the neuronal isoform of NO synthase (nNOS) regulates neurogenesis in the olfactory epithelium, NO has not been implicated in olfactory signal transduction. We now show the expression and function of the endothelial isoform of NO synthase (eNOS) in mature olfactory sensory neurons (OSNs) of adult mice. Using NO-sensitive micro electrodes, we show that stimulation liberates NO from isolated wild-type OSNs, but not from OSNs of eNOS deficient mice. Integrated electrophysiological recordings (electro-olfactograms or EOGs) from the olfactory epithelium of these mice show that NO plays a significant role in modulating adaptation. Evidence for the presence of eNOS in mature mammalian OSNs and its involvement in odorant adaptation implicates NO as an important new element involved in olfactory signal transduction. As a diffusible messenger, NO could also have additional functions related to cross adaptation, regeneration, and maintenance of MOE homeostasis. PMID:19430528

Odor Coding in the Maxillary Palp of the Malaria Vector Mosquito Anopheles gambiae

PubMed Central

Lu, Tan; Qiu, Yu Tong; Wang, Guirong; Kwon, Jae Young; Rutzler, Michael; Kwon, Hyung-Wook; Pitts, R. Jason; van Loon, Joop J.A.; Takken, Willem; Carlson, John R.; Zwiebel, Laurence J.

2011-01-01

Summary Background Many species of mosquitoes, including the major malaria vector Anopheles gambiae, utilize carbon dioxide (CO2) and 1-octen-3-ol as olfactory cues in host-seeking behaviors that underlie their vectorial capacity. However, the molecular and cellular basis of such olfactory responses remains largely unknown. Results Here, we use molecular and physiological approaches coupled with systematic functional analyses to define the complete olfactory sensory map of the An. gambiae maxillary palp, an olfactory appendage that mediates the detection of these compounds. In doing so, we identify three olfactory receptor neurons (ORNs) that are organized in stereotyped triads within the maxillary-palp capitate-peg-sensillum population. One ORN is CO2-responsive and characterized by the coexpression of three receptors that confer CO2 responses, whereas the other ORNs express characteristic odorant receptors (AgORs) that are responsible for their in vivo olfactory responses. Conclusions Our results describe a complete and highly concordant map of both the molecular and cellular olfactory components on the maxillary palp of the adult female An. gambiae mosquito. These results also facilitate the understanding of how An. gambiae mosquitoes sense olfactory cues that might be exploited to compromise their ability to transmit malaria. PMID:17764944

From Nose to Brain: Un-Sensed Electrical Currents Applied in the Nose Alter Activity in Deep Brain Structures

PubMed Central

Weiss, Tali; Shushan, Sagit; Ravia, Aharon; Hahamy, Avital; Secundo, Lavi; Weissbrod, Aharon; Ben-Yakov, Aya; Holtzman, Yael; Cohen-Atsmoni, Smadar; Roth, Yehudah; Sobel, Noam

2016-01-01

Rules linking patterns of olfactory receptor neuron activation in the nose to activity patterns in the brain and ensuing odor perception remain poorly understood. Artificially stimulating olfactory neurons with electrical currents and measuring ensuing perception may uncover these rules. We therefore inserted an electrode into the nose of 50 human volunteers and applied various currents for about an hour in each case. This induced assorted non-olfactory sensations but never once the perception of odor. To validate contact with the olfactory path, we used functional magnetic resonance imaging to measure resting-state brain activity in 18 subjects before and after un-sensed stimulation. We observed stimulation-induced neural decorrelation specifically in primary olfactory cortex, implying contact with the olfactory path. These results suggest that indiscriminate olfactory activation does not equate with odor perception. Moreover, this effort serendipitously uncovered a novel path for minimally invasive brain stimulation through the nose. PMID:27591145

Cortical Feedback Control of Olfactory Bulb Circuits

PubMed Central

Boyd, Alison M.; Sturgill, James F.; Poo, Cindy; Isaacson, Jeffry S.

2013-01-01

SUMMARY Olfactory cortex pyramidal cells integrate sensory input from olfactory bulb mitral and tufted (M/T) cells and project axons back to the bulb. However, the impact of cortical feedback projections on olfactory bulb circuits is unclear. Here, we selectively express channelrhodopsin-2 in olfactory cortex pyramidal cells and show that cortical feedback projections excite diverse populations of bulb interneurons. Activation of cortical fibers directly excites GABAergic granule cells, which in turn inhibit M/T cells. However, we show that cortical inputs preferentially target short axon cells that drive feedforward inhibition of granule cells. In vivo, activation of olfactory cortex that only weakly affects spontaneous M/T cell firing strongly gates odor-evoked M/T cell responses: cortical activity suppresses odor-evoked excitation and enhances odor-evoked inhibition. Together, these results indicate that although cortical projections have diverse actions on olfactory bulb microcircuits, the net effect of cortical feedback on M/T cells is an amplification of odor-evoked inhibition. PMID:23259951

Cyclic-nucleotide–gated cation current and Ca2+-activated Cl current elicited by odorant in vertebrate olfactory receptor neurons

PubMed Central

Li, Rong-Chang; Ben-Chaim, Yair; Yau, King-Wai; Lin, Chih-Chun

2016-01-01

Olfactory transduction in vertebrate olfactory receptor neurons (ORNs) involves primarily a cAMP-signaling cascade that leads to the opening of cyclic-nucleotide–gated (CNG), nonselective cation channels. The consequent Ca2+ influx triggers adaptation but also signal amplification, the latter by opening a Ca2+-activated Cl channel (ANO2) to elicit, unusually, an inward Cl current. Hence the olfactory response has inward CNG and Cl components that are in rapid succession and not easily separable. We report here success in quantitatively separating these two currents with respect to amplitude and time course over a broad range of odorant strengths. Importantly, we found that the Cl current is the predominant component throughout the olfactory dose–response relation, down to the threshold of signaling to the brain. This observation is very surprising given a recent report by others that the olfactory-signal amplification effected by the Ca2+-activated Cl current does not influence the behavioral olfactory threshold in mice. PMID:27647918

Evolution of olfactory receptors.

PubMed

Hoover, Kara C

2013-01-01

Olfactory receptors are a specialized set of receptor cells responsible for the detection of odors. These cells are G protein-coupled receptors and expressed in the cell membranes of olfactory sensory neurons. Once a cell is activated by a ligand, it initiates a signal transduction cascade that produces a nerve impulse to the brain where odor perception is processed. Vertebrate olfactory evolution is characterized by birth-and-death events, a special case of the stochastic continuous time Markov process. Vertebrate fish have three general types of receptor cells (two dedicated to pheromones). Terrestrial animals have different epithelial biology due to the specialized adaptation to detecting airborne odors. Two general classes of olfactory receptor gene reflect the vertebrate marine heritage (Class I) and the derived amphibian, reptile, and mammal terrestrial heritage (Class II). While we know much about olfactory receptor cells, there are still areas where our knowledge is insufficient, such as intra-individual diversity throughout the life time, epigenetic processes acting on olfactory receptors, and association of ligands to specific cells.

Cortical feedback control of olfactory bulb circuits.

PubMed

Boyd, Alison M; Sturgill, James F; Poo, Cindy; Isaacson, Jeffry S

2012-12-20

Olfactory cortex pyramidal cells integrate sensory input from olfactory bulb mitral and tufted (M/T) cells and project axons back to the bulb. However, the impact of cortical feedback projections on olfactory bulb circuits is unclear. Here, we selectively express channelrhodopsin-2 in olfactory cortex pyramidal cells and show that cortical feedback projections excite diverse populations of bulb interneurons. Activation of cortical fibers directly excites GABAergic granule cells, which in turn inhibit M/T cells. However, we show that cortical inputs preferentially target short axon cells that drive feedforward inhibition of granule cells. In vivo, activation of olfactory cortex that only weakly affects spontaneous M/T cell firing strongly gates odor-evoked M/T cell responses: cortical activity suppresses odor-evoked excitation and enhances odor-evoked inhibition. Together, these results indicate that although cortical projections have diverse actions on olfactory bulb microcircuits, the net effect of cortical feedback on M/T cells is an amplification of odor-evoked inhibition. Copyright © 2012 Elsevier Inc. All rights reserved.

Olfactory identification deficit and its relationship with hedonic traits in patients with first-episode schizophrenia and individuals with schizotypy.

PubMed

Zou, Lai-Quan; Zhou, Han-Yu; Lui, Simon S Y; Wang, Yi; Wang, Ya; Gan, Jun; Zhu, Xiong-Zhao; Cheung, Eric F C; Chan, Raymond C K

2018-04-20

Olfactory identification impairments have been consistently found in schizophrenia patients. However, few previous studies have investigated this in first-episode patients. There are also inconsistent findings regarding olfactory identification ability in psychometrically-defined schizotypy individuals. In this study, we directly compared the olfactory identification ability of first-episode schizophrenia patients with schizotypy individuals. The relationship between olfactory identification impairments and hedonic traits was also examined. Thirty-five first-episode schizophrenia patients, 40 schizotypy individuals as defined by the Chapman's Anhedonia Scales and 40 demographically matched controls were recruited. The University of Pennsylvania Smell Identification Test was administered. Hedonic capacity was assessed using the Temporal Experience of Pleasure Scale (TEPS). The results showed that both the schizophrenia and schizotypy groups showed poorer olfactory identification ability than controls, and the impairment was significantly correlated with reduced pleasure experiences. Our findings support olfactory identification impairment as a trait marker for schizophrenia. Copyright © 2018 Elsevier Inc. All rights reserved.

Disruption of centrifugal inhibition to olfactory bulb granule cells impairs olfactory discrimination.

PubMed

Nunez-Parra, Alexia; Maurer, Robert K; Krahe, Krista; Smith, Richard S; Araneda, Ricardo C

2013-09-03

Granule cells (GCs) are the most abundant inhibitory neuronal type in the olfactory bulb and play a critical role in olfactory processing. GCs regulate the activity of principal neurons, the mitral cells, through dendrodendritic synapses, shaping the olfactory bulb output to other brain regions. GC excitability is regulated precisely by intrinsic and extrinsic inputs, and this regulation is fundamental for odor discrimination. Here, we used channelrhodopsin to stimulate GABAergic axons from the basal forebrain selectively and show that this stimulation generates reliable inhibitory responses in GCs. Furthermore, selective in vivo inhibition of GABAergic neurons in the basal forebrain by targeted expression of designer receptors exclusively activated by designer drugs produced a reversible impairment in the discrimination of structurally similar odors, indicating an important role of these inhibitory afferents in olfactory processing.

Human olfactory receptor responses to odorants

PubMed Central

Mainland, Joel D; Li, Yun R; Zhou, Ting; Liu, Wen Ling L; Matsunami, Hiroaki

2015-01-01

Although the human olfactory system is capable of discriminating a vast number of odors, we do not currently understand what chemical features are encoded by olfactory receptors. In large part this is due to a paucity of data in a search space covering the interactions of hundreds of receptors with billions of odorous molecules. Of the approximately 400 intact human odorant receptors, only 10% have a published ligand. Here we used a heterologous luciferase assay to screen 73 odorants against a clone library of 511 human olfactory receptors. This dataset will allow other researchers to interrogate the combinatorial nature of olfactory coding. PMID:25977809

Parasites and a host's sense of smell: reduced chemosensory performance of fathead minnows (Pimephales promelas) infected with a monogenean parasite.

PubMed

Lari, Ebrahim; Goater, Cameron P; Cone, David K; Pyle, Greg G

2017-05-01

Parasites residing within the central nervous system of their hosts have the potential to reduce various components of host performance, but such effects are rarely evaluated. We assessed the olfactory acuity of fathead minnows (Pimephales promelas) infected experimentally with the monogenean Dactylogyrus olfactorius, the adults of which live within the host's olfactory chambers. Olfactory acuity was compared between infected and uninfected hosts by assessing electro-olfactography (EOG) neural responses to chemical stimuli that indicate the presence of food (L-alanine) or the presence of conspecifics (taurocholic acid). We also compared differences in gross morphology of the olfactory epithelium in infected and uninfected minnows. Differences in EOG responses between infected and uninfected minnows to both cue types were non-significant at 30 days post-exposure. By days 60 and 90, coincident with a two times increase in parasite intensity in the olfactory chambers, the EOG responses of infected minnows were 70-90% lower than controls. When infected fish were treated with a parasiticide (Prazipro), olfactory acuity returned to control levels by day 7 post-treatment. The observed reduction in olfactory acuity is best explained by the reduced density of cilia covering the olfactory chambers of infected fish, or by the concomitant increase in the density of mucous cells that cover the olfactory chambers. These morphological changes are likely due to the direct effects of attachment and feeding by individual worms or by indirect effects associated with host responses. Our results show that infection of a commonly occurring monogenean in fathead minnows reduces olfactory acuity. Parasite-induced interference with olfactory performance may reduce a fish's ability to detect, or respond to, chemical cues originating from food, predators, competitors or mates. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

An olfactory demography of a diverse metropolitan population.

PubMed

Keller, Andreas; Hempstead, Margaret; Gomez, Iran A; Gilbert, Avery N; Vosshall, Leslie B

2012-10-10

Human perception of the odour environment is highly variable. People vary both in their general olfactory acuity as well as in if and how they perceive specific odours. In recent years, it has been shown that genetic differences contribute to variability in both general olfactory acuity and the perception of specific odours. Odour perception also depends on other factors such as age and gender. Here we investigate the influence of these factors on both general olfactory acuity and on the perception of 66 structurally and perceptually different odours in a diverse subject population. We carried out a large human olfactory psychophysics study of 391 adult subjects in metropolitan New York City, an ethnically and culturally diverse North American metropolis. 210 of the subjects were women and the median age was 34.6 years (range 19-75). We recorded ~2,300 data points per subject to obtain a comprehensive perceptual phenotype, comprising multiple perceptual measures of 66 diverse odours. We show that general olfactory acuity correlates with gender, age, race, smoking habits, and body type. Young, female, non-smoking subjects had the highest average olfactory acuity. Deviations from normal body type in either direction were associated with decreased olfactory acuity. Beyond these factors we also show that, surprisingly, there are many odour-specific influences of race, age, and gender on olfactory perception. We show over 100 instances in which the intensity or pleasantness perception of an odour is significantly different between two demographic groups. These data provide a comprehensive snapshot of the olfactory sense of a diverse population. Olfactory acuity in the population is most strongly influenced by age, followed by gender. We also show a large number of diverse correlations between demographic factors and the perception of individual odours that may reflect genetic differences as well as different prior experiences with these odours between demographic groups.

An olfactory demography of a diverse metropolitan population

PubMed Central

2012-01-01

Background Human perception of the odour environment is highly variable. People vary both in their general olfactory acuity as well as in if and how they perceive specific odours. In recent years, it has been shown that genetic differences contribute to variability in both general olfactory acuity and the perception of specific odours. Odour perception also depends on other factors such as age and gender. Here we investigate the influence of these factors on both general olfactory acuity and on the perception of 66 structurally and perceptually different odours in a diverse subject population. Results We carried out a large human olfactory psychophysics study of 391 adult subjects in metropolitan New York City, an ethnically and culturally diverse North American metropolis. 210 of the subjects were women and the median age was 34.6 years (range 19–75). We recorded ~2,300 data points per subject to obtain a comprehensive perceptual phenotype, comprising multiple perceptual measures of 66 diverse odours. We show that general olfactory acuity correlates with gender, age, race, smoking habits, and body type. Young, female, non-smoking subjects had the highest average olfactory acuity. Deviations from normal body type in either direction were associated with decreased olfactory acuity. Beyond these factors we also show that, surprisingly, there are many odour-specific influences of race, age, and gender on olfactory perception. We show over 100 instances in which the intensity or pleasantness perception of an odour is significantly different between two demographic groups. Conclusions These data provide a comprehensive snapshot of the olfactory sense of a diverse population. Olfactory acuity in the population is most strongly influenced by age, followed by gender. We also show a large number of diverse correlations between demographic factors and the perception of individual odours that may reflect genetic differences as well as different prior experiences with these odours between demographic groups. PMID:23046643

Assessment of olfactory threshold in patients undergoing radiotherapy for head and neck malignancies.

PubMed

Jalali, Mir Mohammad; Gerami, Hooshang; Rahimi, Abbas; Jafari, Manizheh

2014-10-01

Radiotherapy is a common treatment modality for patients with head and neck malignancies. As the nose lies within the field of radiotherapy of the head and neck, the olfactory fibers and olfactory receptors may be affected by radiation. The aim of this study was to evaluate changes in olfactory threshold in patients with head and neck malignancies who have received radiation to the head and neck. The olfactory threshold of patients with head and neck malignancies was assessed prospectively before radiation therapy and serially for up to 6 months after radiotherapy using sniff bottles. In vivo dosimetry was performed using 82 LiF (MCP) chips and a thermoluminescent dosimeter (TLD) system. Sixty-one patients were recruited before radiotherapy was commenced. Seven patients did not return for evaluation after radiation. Fifty-four patients were available for follow-up assessment (28 women, 26 men; age, 22-86 years; median, 49 years). Total radiation dose was 50.1 Gy (range, 30-66 Gy). Mean olfactory threshold scores were found to deteriorate significantly at various timepoints after radiotherapy (11.7 before radiotherapy versus 4.0 at Month 6, general linear model, P<0.0001). With in vivo dosimetry, we found that the median measured dose to the olfactory area was 334 µC. We also identified a cutoff point according to the dose to the olfactory epithelium. Olfactory threshold was significantly decreased 2-6 weeks after initiation of therapy, with cumulative local radiation >135 µC (Mann-Whitney U test, P=0.01). Deterioration in olfactory threshold scores was found at 6 months after initiation of radiation therapy. Provided that these results are reproducible, an evaluation of olfactory functioning in patients with head and neck malignancies using in vivo dosimetry may be useful for determining the optimal dose for patients treated with conformal radiotherapy techniques while avoiding the side effects of radiation.

Respiratory and olfactory turbinal size in canid and arctoid carnivorans.

PubMed

Green, Patrick A; Van Valkenburgh, Blaire; Pang, Benison; Bird, Deborah; Rowe, Timothy; Curtis, Abigail

2012-12-01

Within the nasal cavity of mammals is a complex scaffold of paper-thin bones that function in respiration and olfaction. Known as turbinals, the bones greatly enlarge the surface area available for conditioning inspired air, reducing water loss, and improving olfaction. Given their functional significance, the relative development of turbinal bones might be expected to differ among species with distinct olfactory, thermoregulatory and/or water conservation requirements. Here we explore the surface area of olfactory and respiratory turbinals relative to latitude and diet in terrestrial Caniformia, a group that includes the canid and arctoid carnivorans (mustelids, ursids, procyonids, mephitids, ailurids). Using high-resolution computed tomography x-ray scans, we estimated respiratory and olfactory turbinal surface area and nasal chamber volume from three-dimensional virtual models of skulls. Across the Caniformia, respiratory surface area scaled isometrically with estimates of body size and there was no significant association with climate, as estimated by latitude. Nevertheless, one-on-one comparisons of sister taxa suggest that arctic species may have expanded respiratory turbinals. Olfactory surface area scaled isometrically among arctoids, but showed positive allometry in canids, reflecting the fact that larger canids, all of which are carnivorous, had relatively greater olfactory surface areas. In addition, among the arctoids, large carnivorous species such as the polar bear (Ursus maritimus) and wolverine (Gulo gulo) also displayed enlarged olfactory turbinals. More omnivorous caniform species that feed on substantial quantities of non-vertebrate foods had less expansive olfactory turbinals. Because large carnivorous species hunt widely dispersed prey, an expanded olfactory turbinal surface area may improve a carnivore's ability to detect prey over great distances using olfactory cues. © 2012 The Authors. Journal of Anatomy © 2012 Anatomical Society.

Immunocytochemical characterisation of ensheathing glia in the olfactory and vomeronasal systems of Ambystoma mexicanum (Caudata: Ambystomatidae).

PubMed

Lazzari, Maurizio; Bettini, Simone; Franceschini, Valeria

2016-03-01

The olfactory and vomeronasal systems of vertebrates are characterised by neurogenesis occurring throughout life. The regenerative ability of olfactory receptor neurons relies on specific glial cells, the olfactory and vomeronasal axon-surrounding cells. Numerous studies have examined mammalian olfactory ensheathing cells which are considered potential candidates for spinal cord injury repair using cell-based therapy. With regard to non-mammalian vertebrates, limited information is available on these glial cells in fish, and there is no information on them in terrestrial anamniotes, the amphibians. In the present research, we studied the immunocytochemical characteristics of axon-surrounding cells in Ambystoma mexicanum. Urodeles have relatively simple olfactory and vomeronasal systems, and represent a good model for studying ensheathing cells in extant representatives of basal tetrapods. Sections from the decalcified heads of A. mexicanum were immunocytochemically processed for the detection of proteins used in research on mammalian olfactory-ensheathing cells. S100, GFAP and NCAM were clearly observed. p75NTR, Gal-1 and PSA-NCAM showed weak staining. No vimentin immunopositivity was observed. The corresponding areas of the olfactory and vomeronasal pathways displayed the same staining characteristics, with the exception of Gal-1, p75NTR and PSA-NCAM in the mucosae. The degree of marker expression was not uniform throughout the sensory pathways. In contrast to fish, both olfactory and vomeronasal nerves displayed uniform staining intensity. This study showed that some markers for mammalian and fish-ensheathing glia are also applicable in urodeles. The olfactory systems of vertebrates show similarities, and also clear dissimilarities. Further investigations are required to ascertain the functional significance of these regional and interspecific differences.

Gustatory and olfactory sensitivity in patients with anorexia and bulimia in the course of treatment.

PubMed

Aschenbrenner, Katja; Scholze, Ninette; Joraschky, Peter; Hummel, Thomas

2008-12-01

The majority of studies on taste and smell in eating disorders have revealed several alterations of olfactory or gustatory functions. Aim of this prospective study was to employ detailed olfactory and gustatory testing in female subjects of three homogenous groups - anorexia nervosa, bulimia nervosa and healthy controls - and to look at the effects of treatment on these measures. Sixteen hospitalized female patients with anorexia (restricting type, mean age [M]=24.5 years), 24 female patients with bulimia (purging type, M=24.3 years) as well as 23 healthy controls (M=24.5 years) received olfactory ("Sniffin' Sticks") and gustatory testing ("Taste Strips"). Group differences in olfactory and gustatory sensitivity, body mass index (BMI), the Beck depression inventory, the eating attitudes test (EAT), and the influence of therapy on gustatory and olfactory function were investigated. (1) Group differences were present for odor discrimination and overall olfactory function with anorexic patients having the lowest scores. (2) Regarding taste function, controls scored higher than patients with anorexia. (3) At admission small but significant correlations were found between overall olfactory function and body weight (r(63)=0.35), BMI (r(63) = 0.37), and EAT score (r(63) = -0.27). Similarly, (4) the taste test score correlated significantly with body weight (r(63)= 0.48), and BMI (r(63) = 0.45). Finally, (5) at discharge overall olfactory and gustatory function were significantly higher compared to admission in anorexic patients. As compared to healthy controls and bulimic patients our results show lowered olfactory and gustatory sensitivities in anorexic patients that improved with increasing BMI and decreasing eating pathology in the course of treatment.

Translocation of Inhaled Ultrafine Manganese Oxide Particles to the Central Nervous System

PubMed Central

Elder, Alison; Gelein, Robert; Silva, Vanessa; Feikert, Tessa; Opanashuk, Lisa; Carter, Janet; Potter, Russell; Maynard, Andrew; Ito, Yasuo; Finkelstein, Jacob; Oberdörster, Günter

2006-01-01

Background Studies in monkeys with intranasally instilled gold ultrafine particles (UFPs; < 100 nm) and in rats with inhaled carbon UFPs suggested that solid UFPs deposited in the nose travel along the olfactory nerve to the olfactory bulb. Methods To determine if olfactory translocation occurs for other solid metal UFPs and assess potential health effects, we exposed groups of rats to manganese (Mn) oxide UFPs (30 nm; ~ 500 μg/m3) with either both nostrils patent or the right nostril occluded. We analyzed Mn in lung, liver, olfactory bulb, and other brain regions, and we performed gene and protein analyses. Results After 12 days of exposure with both nostrils patent, Mn concentrations in the olfactory bulb increased 3.5-fold, whereas lung Mn concentrations doubled; there were also increases in striatum, frontal cortex, and cerebellum. Lung lavage analysis showed no indications of lung inflammation, whereas increases in olfactory bulb tumor necrosis factor-α mRNA (~ 8-fold) and protein (~ 30-fold) were found after 11 days of exposure and, to a lesser degree, in other brain regions with increased Mn levels. Macrophage inflammatory protein-2, glial fibrillary acidic protein, and neuronal cell adhesion molecule mRNA were also increased in olfactory bulb. With the right nostril occluded for a 2-day exposure, Mn accumulated only in the left olfactory bulb. Solubilization of the Mn oxide UFPs was < 1.5% per day. Conclusions We conclude that the olfactory neuronal pathway is efficient for translocating inhaled Mn oxide as solid UFPs to the central nervous system and that this can result in inflammatory changes. We suggest that despite differences between human and rodent olfactory systems, this pathway is relevant in humans. PMID:16882521

Respiratory and olfactory turbinal size in canid and arctoid carnivorans

PubMed Central

Green, Patrick A; Valkenburgh, Blaire; Pang, Benison; Bird, Deborah; Rowe, Timothy; Curtis, Abigail

2012-01-01

Within the nasal cavity of mammals is a complex scaffold of paper-thin bones that function in respiration and olfaction. Known as turbinals, the bones greatly enlarge the surface area available for conditioning inspired air, reducing water loss, and improving olfaction. Given their functional significance, the relative development of turbinal bones might be expected to differ among species with distinct olfactory, thermoregulatory and/or water conservation requirements. Here we explore the surface area of olfactory and respiratory turbinals relative to latitude and diet in terrestrial Caniformia, a group that includes the canid and arctoid carnivorans (mustelids, ursids, procyonids, mephitids, ailurids). Using high-resolution computed tomography x-ray scans, we estimated respiratory and olfactory turbinal surface area and nasal chamber volume from three-dimensional virtual models of skulls. Across the Caniformia, respiratory surface area scaled isometrically with estimates of body size and there was no significant association with climate, as estimated by latitude. Nevertheless, one-on-one comparisons of sister taxa suggest that arctic species may have expanded respiratory turbinals. Olfactory surface area scaled isometrically among arctoids, but showed positive allometry in canids, reflecting the fact that larger canids, all of which are carnivorous, had relatively greater olfactory surface areas. In addition, among the arctoids, large carnivorous species such as the polar bear (Ursus maritimus) and wolverine (Gulo gulo) also displayed enlarged olfactory turbinals. More omnivorous caniform species that feed on substantial quantities of non-vertebrate foods had less expansive olfactory turbinals. Because large carnivorous species hunt widely dispersed prey, an expanded olfactory turbinal surface area may improve a carnivore's ability to detect prey over great distances using olfactory cues. PMID:23035637

Oxytocin administration selectively improves olfactory detection thresholds for lyral in patients with schizophrenia

PubMed Central

Woolley, J.D.; Lam, O.; Chuang, B.; Ford, J.M.; Mathalon, D.H.; Vinogradov, S.

2015-01-01

Summary Background Olfaction plays an important role in mammalian social behavior. Olfactory deficits are common in schizophrenia and correlate with negative symptoms and low social drive. Despite their prominence and possible clinical relevance, little is understood about the pathological mechanisms underlying olfactory deficits in schizophrenia and there are currently no effective treatments for these deficits. The prosocial neuropeptide oxytocin may affect the olfactory system when administered intranasally to humans and there is growing interest in its therapeutic potential in schizophrenia. Methods To examine this model, we administered 40 IU of oxytocin and placebo intranasally to 31 patients with a schizophrenia spectrum illness and 34 age-matched healthy control participants in a randomized, double-blind, placebo-controlled, cross-over study. On each test day, participants completed an olfactory detection threshold test for two different odors: (1) lyral, a synthetic fragrance compound for which patients with schizophrenia have specific olfactory detection threshold deficits, possibly related to decreased cyclic adenosine 3′,5′-monophosphate (cAMP) signaling; and (2) anise, a compound for which olfactory detection thresholds change with menstrual cycle phase in women. Results On the placebo test day, patients with schizophrenia did not significantly differ from healthy controls in detection of either odor. We found that oxytocin administration significantly and selectively improved olfactory detection thresholds for lyral but not for anise in patients with schizophrenia. In contrast, oxytocin had no effect on detection of either odor in healthy controls. Discussion Our data indicate that oxytocin administration may ameliorate olfactory deficits in schizophrenia and suggest the effects of intranasal oxytocin may extend to influencing the olfactory system. Given that oxytocin has been found to increase cAMP signaling in vitro a possible mechanism for these effects is discussed. PMID:25637811

Oxytocin administration selectively improves olfactory detection thresholds for lyral in patients with schizophrenia.

PubMed

Woolley, J D; Lam, O; Chuang, B; Ford, J M; Mathalon, D H; Vinogradov, S

2015-03-01

Olfaction plays an important role in mammalian social behavior. Olfactory deficits are common in schizophrenia and correlate with negative symptoms and low social drive. Despite their prominence and possible clinical relevance, little is understood about the pathological mechanisms underlying olfactory deficits in schizophrenia and there are currently no effective treatments for these deficits. The prosocial neuropeptide oxytocin may affect the olfactory system when administered intranasally to humans and there is growing interest in its therapeutic potential in schizophrenia. To examine this model, we administered 40IU of oxytocin and placebo intranasally to 31 patients with a schizophrenia spectrum illness and 34 age-matched healthy control participants in a randomized, double-blind, placebo-controlled, cross-over study. On each test day, participants completed an olfactory detection threshold test for two different odors: (1) lyral, a synthetic fragrance compound for which patients with schizophrenia have specific olfactory detection threshold deficits, possibly related to decreased cyclic adenosine 3',5'-monophosphate (cAMP) signaling; and (2) anise, a compound for which olfactory detection thresholds change with menstrual cycle phase in women. On the placebo test day, patients with schizophrenia did not significantly differ from healthy controls in detection of either odor. We found that oxytocin administration significantly and selectively improved olfactory detection thresholds for lyral but not for anise in patients with schizophrenia. In contrast, oxytocin had no effect on detection of either odor in healthy controls. Our data indicate that oxytocin administration may ameliorate olfactory deficits in schizophrenia and suggest the effects of intranasal oxytocin may extend to influencing the olfactory system. Given that oxytocin has been found to increase cAMP signaling in vitro a possible mechanism for these effects is discussed. Published by Elsevier Ltd.

Importance of unilateral examination in olfactometry.

PubMed

Furukawa, M; Kamide, M; Miwa, T; Umeda, R

1988-01-01

Hyposmia, the decreased sense of smell, and anosmia, the loss of sense of smell, may be unilateral or bilateral. If the olfactory acuity examined by means of bilateral test is normal, olfactory disorders are not found; unilateral examination is therefore necessary for definite evaluation of olfactory acuity. As evidence, 7 cases out of 94 patients with chronic rhinosinusitis and 6 cases out of 12 patients who received the surgery of anterior cranial fossa showed definite different olfactory threshold between nasal cavities, and there were no patients who recognized the diminished sense of smell in spite of unilateral high olfactory threshold. Additionally, we have experienced that a patient with brain tumor was diagnosed by the help of unilateral olfactory test. We thus strongly recommend the unilateral olfactometry as a method for simple and reliable test in clinical measurement of the sense of smell.

Role of a Ubiquitously Expressed Receptor in the Vertebrate Olfactory System

PubMed Central

DeMaria, Shannon; Berke, Allison P.; Van Name, Eric; Heravian, Anisa; Ferreira, Todd

2013-01-01

Odorant cues are recognized by receptors expressed on olfactory sensory neurons, the primary sensory neurons of the olfactory epithelium. Odorant receptors typically obey the “one receptor, one neuron” rule, in which the receptive field of the olfactory neuron is determined by the singular odorant receptor that it expresses. Odor-evoked receptor activity across the population of olfactory neurons is then interpreted by the brain to identify the molecular nature of the odorant stimulus. In the present study, we characterized the properties of a C family G-protein-coupled receptor that, unlike most other odorant receptors, is expressed in a large population of microvillous sensory neurons in the zebrafish olfactory epithelium and the mouse vomeronasal organ. We found that this receptor, OlfCc1 in zebrafish and its murine ortholog Vmn2r1, is a calcium-dependent, low-sensitivity receptor specific for the hydrophobic amino acids isoleucine, leucine, and valine. Loss-of-function experiments in zebrafish embryos demonstrate that OlfCc1 is required for olfactory responses to a diverse mixture of polar, nonpolar, acidic, and basic amino acids. OlfCc1 was also found to promote localization of other OlfC receptor family members to the plasma membrane in heterologous cells. Together, these results suggest that the broadly expressed OlfCc1 is required for amino acid detection by the olfactory system and suggest that it plays a role in the function and/or intracellular trafficking of other olfactory and vomeronasal receptors with which it is coexpressed. PMID:24048853

The olfactory fascia: an evo-devo concept of the fibrocartilaginous nose.

PubMed

Jankowski, Roger; Rumeau, Cécile; de Saint Hilaire, Théophile; Tonnelet, Romain; Nguyen, Duc Trung; Gallet, Patrice; Perez, Manuela

2016-12-01

Evo-devo is the science that studies the link between evolution of species and embryological development. This concept helps to understand the complex anatomy of the human nose. The evo-devo theory suggests the persistence in the adult of an anatomical entity, the olfactory fascia, that unites the cartilages of the nose to the olfactory mucosa. We dissected two fresh specimens. After resecting the superficial tissues of the nose, dissection was focused on the disarticulation of the fibrocartilaginous noses from the facial and skull base skeleton. Dissection shows two fibrocartilaginous sacs that were invaginated side-by-side in the midface and attached to the anterior skull base. These membranous sacs were separated in the midline by the perpendicular plate of the ethmoid. Their walls contained the alar cartilages and the lateral expansions of the septolateral cartilage, which we had to separate from the septal cartilage. The olfactory mucosa was located inside their cranial ends. The olfactory fascia is a continuous membrane uniting the nasal cartilages to the olfactory mucosa. Its origin can be found in the invagination and differentiation processes of the olfactory placodes. The fibrous portions of the olfactory fascia may be described as ligaments that unit the different components of the olfactory fascia one to the other and the fibrocartilaginous nose to the facial and skull base skeleton. The basicranial ligaments, fixing the fibrocartilaginous nose to the skull base, represent key elements in the concept of septorhinoplasty by disarticulation.

Efferent connections of the olfactory bulb in the opossum (Didelphis marsupialis aurita): a Fink-Heimer study.

PubMed

Shammah-Lagnado, S J; Negrão, N

1981-09-01

The efferent concentrations of the olfactory bulb (OB) in the opossum (Didelphis marsupialis aurita) were studied by the aid of the Fink-Heimer technique. Following lesions restricted to the OB, ipsilateral degenerating fibers entered the lateral olfactory tract and were treated to terminal fields essentially limited to the outer portion of the plexiform layer (sublamina IA) of the following structures: all the subdivisions of the anterior olfactory nucleus, the rostroventral tenia tecta, the full extent of the olfactory tubercle, the nucleus of the lateral olfactory tract, the anterior portion of the medial amygdaloid nucleus, the whole cortical amygdaloid nucleus (in the posteromedial subdivision of this structure the degeneration was very scanty), and the sulcal, piriform, and lateral entorhinal cortices. Some degree of topographical organization in the OB projections was noticed in the rostral portion of the lateral olfactory tract and within the external and lateral subdivisions of the anterior olfactory nucleus. In another series of experiments, when the lesion also involved the accessory olfactory bulb, heavy terminal degeneration occurred along the whole extent of the medial amygdaloid nucleus and in the posteromedial subdivision of the cortical amygdaloid nucleus. These findings indicate that, although very similar to those described in other mammals, the OB efferent connections in the opossum present some peculiarities; namely, the existence of dense terminal fields in the sulcal cortex and in the rostral district of the medial amygdaloid nucleus.

Directional coupling from the olfactory bulb to the hippocampus during a go/no-go odor discrimination task.

PubMed

Gourévitch, Boris; Kay, Leslie M; Martin, Claire

2010-05-01

The hippocampus and olfactory regions are anatomically close, and both play a major role in memory formation. However, the way they interact during odor processing is still unclear. In both areas, strong oscillations of the local field potential (LFP) can be recorded, and are modulated by behavior. In particular, in the olfactory system, the beta rhythm (15-35 Hz) is associated with cognitive processing of an olfactory stimulus. Using LFP recordings in the olfactory bulb and dorsal and ventral hippocampus during performance of an olfactory go/no-go task in rats, we previously showed that beta oscillations are also present in the hippocampus, coherent with those in the olfactory bulb, during odor sampling. In this study, we provide further insight into information transfer in the olfacto-hippocampal network by using directional coherence (DCOH estimate), a method based on the temporal relation between two or more signals in the frequency domain. In the theta band (6-12 Hz), coherence between the olfactory bulb (OB) and the hippocampus (HPC) is weak and can be both in the feedback and feedforward directions. However, at this frequency, modulation of the coupling between the dorsal and ventral hippocampus is seen during stimulus expectation versus odor processing. In the beta frequency band (15-35 Hz), analysis showed a strong unidirectional coupling from the OB to dorsal and ventral HPC, indicating that, during odor processing, beta oscillations in the hippocampus are driven by the olfactory bulb.

Annual life-history dependent seasonal differences in neural activity of the olfactory system between non-migratory and migratory songbirds.

PubMed

Rastogi, Ashutosh; Surbhi; Malik, Shalie; Rani, Sangeeta; Kumar, Vinod

2016-01-01

Present study investigated seasonal plasticity in neural activity of the olfactory system, and assessed whether this was influenced by differences in seasonal life-history states (LHSs) between the non-migratory and migratory birds. Brains of non-migratory Indian weaver birds and migratory redheaded buntings were processed for ZENK immunohistochemistry, a marker of neuronal activation, at the times of equinoxes (March, September) and solstices (June, December), which correspond with the periods of different seasonal LHSs during the year. Immunoreactivity was quantified in brain regions comprising the olfactory system viz. olfactory bulb (OB), anterior olfactory nucleus (AON), prepiriform cortex (CPP), lateral olfactory tract (LOT) and olfactory cortex (piriform cortex, CPI; lateral olfactory cortex, LOC). In weaver birds, ZENK-like immunoreactive (ZENK-lir) cells were significantly higher in all the brain areas during post-breeding season (September) than during the other seasons; OBs had higher neuronal activity in the breeding season (June), however. A similar neural activity pattern but at enhanced levels was found in migratory buntings almost all the year. These results for the first time show LHS-associated differences in the seasonal plasticity of a sensory system between the non-migratory and migratory songbirds. Copyright © 2015 Elsevier B.V. All rights reserved.

Investigation of initial changes in the mouse olfactory epithelium following a single intravenous injection of vincristine sulphate.

PubMed

Kai, Kiyonori; Yoshida, Mitsuyoshi; Sugawara, Tadaki; Kato, Michiyuki; Uchida, Kazuyuki; Yamaguchi, Ryoji; Tateyama, Susumu; Furuhuma, Kazushisa

2005-01-01

To investigate initial changes in the olfactory epithelium, vincristine sulphate (VCR) was administered intravenously once to male BALB/c mice on day 1 in comparison with unilateral bulbectomy (UBT). The light and electron microscopy of the olfactory epithelium, nerve and/or bulb with BrdU-morphometry was performed sequentially. Further, whole-body radioluminography was conducted at 1 and 24 hours postdose. Apoptosis and an increased number of mitotic cells with a tendency toward decreasing BrdU-positive olfactory epithelial cell counts were observed in olfactory epithelial cells at 6 hours postdose of VCR and became more pronounced at 24 hours postdose. These changes disappeared on days 4 or 15, but minimal axonal degeneration was seen in the olfactory nerve from day 4 onward. Semiquantitative measurement of VCR levels in the ethmoturbinals elicited high drug retention even 24 hours after administration. In contrast, UBT showed no effect on mitosis and BrdU-positive cell counts at 6 hours postdose, but severe lesions in the olfactory epithelium and nerve were seen on days 2, 4, and/or 15. The above results suggest that the initial event of VCR-induced apoptosis in the mouse olfactory epithelium would be mitotic arrest with high drug retention, unlike that evoked by UBT.

Gross anatomy and histology of the olfactory rosette of the shark Heptranchias perlo.

PubMed

Ferrando, Sara; Gallus, Lorenzo; Amaroli, Andrea; Gambardella, Chiara; Waryani, Baradi; Di Blasi, Davide; Vacchi, Marino

2017-06-01

Sharks belonging to the family Hexanchidae have six or seven gill slits, unlike all other elasmobranchs, which have five gill slits. Their olfactory organs have a round shape, which is common for holocephalans, but not for elasmobranchs. Thus, the shape of the olfactory organ represents a further, less striking, peculiarity of this family among elasmobranchs. Despite that, the microscopic anatomy and histology of the olfactory organ have not yet been studied in any species of this family. Here, an anatomical and histological description of the olfactory organ of the sharpnose sevengill shark Heptranchias perlo is given. The organ is a rosette, with a central raphe and 31-34 primary lamellae, which bear secondary lamellae with a more or less branched shape. The elastic connective capsule which envelops the olfactory rosette possibly changes its shape along with water influx. In the olfactory epithelium, the supporting cells also have a secretory function, while no specialized mucous cells are visible; regarding this feature the olfactory epithelium of H. perlo differs from that of other chondrichthyan species. The immunohistochemical investigation of the sensory epithelium shows the absence of immunoreactivity for Gαolf in receptor neurons, which confirms previous observations in Chondrichthyes. Copyright © 2017 Elsevier GmbH. All rights reserved.

The Evaluation of Olfactory Function in Patients With Schizophrenia.

PubMed

Robabeh, Soleimani; Mohammad, Jalali Mir; Reza, Ahmadi; Mahan, Badri

2015-04-23

The aim of this study was to compare olfactory threshold, smell identification, intensity and pleasantness ratings between patients with schizophrenia and healthy controls, and (2) to evaluate correlations between ratings of olfactory probes and illness characteristics. Thirty one patients with schizophrenia and 31 control subjects were assessed with the olfactory n-butanol threshold test, the Iran smell identification test (Ir-SIT), and the suprathreshold amyl acetate odor intensity and odor pleasantness rating test. All olfactory tasks were performed unirhinally. Patients with schizophrenia showed disrupted olfaction in all four measures. Longer duration of schizophrenia was associated with a larger impairment of olfactory threshold or microsmic range on the Ir-SIT (P=0.04, P=0.05, respectively). In patients with schizophrenia, female subjects' ratings of pleasantness followed the same trend as control subjects, whereas male patients' ratings showed an opposite trend. Patients exhibiting high positive score on the positive and negative syndrome scale (PANSS) performed better on the olfactory threshold test (r=0.37, P=0.04). The higher odor pleasantness ratings of patients were associated with presence of positive symptoms. The results suggest that both male and female patients with schizophrenia had difficulties on the olfactory threshold and smell identification tests, but appraisal of odor pleasantness was more disrupted in male patients.

The effects of partial sleep restriction and altered sleep timing on olfactory performance.

PubMed

McNeil, J; Forest, G; Hintze, L J; Brunet, J-F; Doucet, É

2017-12-01

Olfaction can increase the drive to eat and may partially explain the consistent increases in energy intake (EI) following sleep restriction. We investigated the effects of 50% sleep restriction with altered sleep timing on olfactory performance. We also evaluated whether changes (Δ) in olfactory performance were associated with Δ24 h EI. Twelve men and six women (age: 23±4 years; BMI: 23±3 kg/m 2 ) completed three randomized cross-over conditions: habitual sleep duration, 50% sleep restriction with advanced wake-time, and 50% sleep restriction with delayed bedtime. Sleep was measured in-laboratory (polysomnography). Olfactory performance ('sniffin sticks') and 24 h EI (food menu) were evaluated the next day. A trend for a significant condition*sex interaction was noted for threshold-discrimination-identification (TDI) scores (P=0.09); TDI scores were lowest in women and highest in men, following sleep restriction with advanced wake-time. Δolfactory performance were not associated with Δ24 h EI. The impact of sleep restriction on olfactory performance may differ between sexes. Changes in olfactory performance were not associated with changes in 24 h EI. Studies investigating prolonged effects of sleep loss on the relationship between olfactory performance with EI are needed.

Unilateral endonasal transcribriform approach with septal transposition for olfactory groove meningioma: can olfaction be preserved?

PubMed

Youssef, A Samy; Sampath, Raghuram; Freeman, Jacob L; Mattingly, Jameson K; Ramakrishnan, Vijay R

2016-10-01

Loss of olfaction has been considered inevitable in endoscopic endonasal resection of olfactory groove meningiomas. Olfaction preservation may be feasible through an endonasal unilateral transcribriform approach, with the option for expansion using septal transposition and contralateral preservation of the olfactory apparatus. An expanded unilateral endonasal transcribriform approach with septal transposition was performed in five cadaver heads. The approach was applied in a surgical case of a 24 × 26-mm olfactory groove meningioma originating from the right cribriform plate with partially intact olfaction. The surgical approach offered adequate exposure to the anterior skull base bilaterally. The nasal/septal mucosa was preserved on the contralateral side. Gross total resection of the meningioma was achieved with the successful preservation of the contralateral olfactory apparatus and preoperative olfaction. Six months later, the left nasal cavity showed no disruption of the mucosal lining and the right side was at the appropriate stage of healing for a harvested nasoseptal flap. One year later, the preoperative olfactory function was intact and favorably viewed by the patient. Objective testing of olfaction showed microsomia. Olfaction preservation may be feasible in the endoscopic endonasal resection of a unilateral olfactory groove meningioma through a unilateral transcribriform approach with septal transposition and preservation of the contralateral olfactory apparatus.

Parallel processing in the honeybee olfactory pathway: structure, function, and evolution.

PubMed

Rössler, Wolfgang; Brill, Martin F

2013-11-01

Animals face highly complex and dynamic olfactory stimuli in their natural environments, which require fast and reliable olfactory processing. Parallel processing is a common principle of sensory systems supporting this task, for example in visual and auditory systems, but its role in olfaction remained unclear. Studies in the honeybee focused on a dual olfactory pathway. Two sets of projection neurons connect glomeruli in two antennal-lobe hemilobes via lateral and medial tracts in opposite sequence with the mushroom bodies and lateral horn. Comparative studies suggest that this dual-tract circuit represents a unique adaptation in Hymenoptera. Imaging studies indicate that glomeruli in both hemilobes receive redundant sensory input. Recent simultaneous multi-unit recordings from projection neurons of both tracts revealed widely overlapping response profiles strongly indicating parallel olfactory processing. Whereas lateral-tract neurons respond fast with broad (generalistic) profiles, medial-tract neurons are odorant specific and respond slower. In analogy to "what-" and "where" subsystems in visual pathways, this suggests two parallel olfactory subsystems providing "what-" (quality) and "when" (temporal) information. Temporal response properties may support across-tract coincidence coding in higher centers. Parallel olfactory processing likely enhances perception of complex odorant mixtures to decode the diverse and dynamic olfactory world of a social insect.

Rapidly fluctuating anosmia: A clinical sign for unilateral smell impairment.

PubMed

Negoias, Simona; Friedrich, Hergen; Caversaccio, Marco D; Landis, Basile N

2016-02-01

Reports about fluctuating olfactory deficits are rare, as are reports of unilateral olfactory loss. We present a case of unilateral anosmia with contralateral normosmia, presenting as rapidly fluctuating anosmia. The olfactory fluctuation occurred in sync with the average nasal cycle duration. Examination after nasal decongestion, formal smell testing, and imaging revealed unilateral, left-sided anosmia of sinonasal cause, with right-sided normosmia. We hypothesize that the nasal cycle induced transient anosmia when blocking the normosmic side. Fluctuating olfactory deficits might hide a unilateral olfactory loss and require additional unilateral testing and thorough workup. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Is There Any Effect on Smell and Taste Functions with Levothyroxine Treatment in Subclinical Hypothyroidism?

PubMed

Baskoy, Kamil; Ay, Seyid Ahmet; Altundag, Aytug; Kurt, Onuralp; Salihoglu, Murat; Deniz, Ferhat; Tekeli, Hakan; Yonem, Arif; Hummel, Thomas

2016-01-01

Subclinical hypothyroidism has been accused for coronary heart disease, lipid metabolism disorders, neuropsychiatric disorders, infertility or pregnancy related problems with various strength of evidence. Currently there is insufficient knowledge about olfaction and taste functions in subclinical hypothyroidism. Aim of the present study is to investigate the degree of smell and taste dysfunction in patients with subclinical hypothyroidism. 28 subclinical hypothyroid patients, and 31 controls enrolled in the prospective study in Istanbul, Turkey. Subclinical hypothyroid patients were treated with L-thyroxine for 3 months. Psychophysiological olfactory testing was performed using odor dispensers similar to felt-tip pens ("Sniffin' Sticks", Burghart, Wedel, Germany). Taste function tests were made using "Taste Strips" (Burghart, Wedel, Germany) which are basically tastant adsorbed filter paper strip. Patients scored lower on psychophysical olfactory tests than controls (odor thresholds:8.1±1.0 vs 8.9±1.1, p = 0.007; odor discrimination:12.4±1.3 vs 13.1±0.9, p = 0.016; odor identification:13.1±0.9 vs 14.0±1.1, p = 0.001; TDI score: 33.8±2.4 vs 36.9±2.1, p = 0.001). In contrast, results from psychophysical gustatory tests showed only a decreased score for "bitter" in patients, but not for other tastes (5.9±1.8 vs 6.6±1.0, p = 0.045). Three month after onset of treatment olfactory test scores already indicated improvement (odor thresholds:8.1±1.0 vs 8.6±0.6, p<0.001; odor discrimination:12.4±1.31 vs 12.9±0.8, p = 0.011; odor identification:13.1±0.9 vs 13.9±0.8, p<0.001; TDI scores:33.8±2.4 vs 35.5±1.7, p<0.001) respectively. Taste functions did not differ between groups for sweet, salty and, sour tastes but bitter taste was improved after 3 months of thyroxin substitution (patients:5.9±1.8 vs 6.6±1.2, p = 0.045). Correlation of changes in smell and taste, with thyroid function test were also evaluated. TSH, fT4 were found have no correlation with smell and taste changes with treatment. However bitter taste found positively correlated with T3 with treatment(r: 0.445, p: 0.018). Subclinical hypothyroid patients exhibited a significantly decreased olfactory sensitivity; in addition, bitter taste was significantly affected. Most importantly, these deficits can be remedied on average within 3 months with adequate treatment.

Changes of olfactory abilities in relation to age: odor identification in more than 1400 people aged 4 to 80 years.

PubMed

Sorokowska, A; Schriever, V A; Gudziol, V; Hummel, C; Hähner, A; Iannilli, E; Sinding, C; Aziz, M; Seo, H S; Negoias, S; Hummel, T

2015-08-01

The currently presented large dataset (n = 1,422) consists of results that have been assembled over the last 8 years at science fairs using the 16-item odor identification part of the "Sniffin' Sticks". In this context, the focus was on olfactory function in children; in addition before testing, we asked participants to rate their olfactory abilities and the patency of the nasal airways. We reinvestigated some simple questions, e.g., differences in olfactory odor identification abilities in relation to age, sex, self-ratings of olfactory function and nasal patency. Three major results evolved: first, consistent with previously published reports, we found that identification scores of the youngest and the oldest participants were lower than the scores obtained by people aged 20-60. Second, we observed an age-related increase in the olfactory abilities of children. Moreover, the self-assessed olfactory abilities were related to actual performance in the smell test, but only in adults, and self-assessed nasal patency was not related to the "Sniffin' Sticks" identification score.

Gray matter alteration in isolated congenital anosmia patient: a voxel-based morphometry study.

PubMed

Yao, Linyin; Yi, Xiaoli; Wei, Yongxiang

2013-09-01

Decreased volume of gray matter (GM) was observed in olfactory loss in patients with neurodegenerative disorder. However, GM volume has not yet been investigated in isolated congenital anosmia (ICA) people. We herewith investigated the volume change of gray matter of an ICA boy by morphometric analysis of magnetic resonance images (voxel-based morphometry), and compared with that of 20 age-matched healthy controls. ICA boy presented a significant decrease in GM volume in the orbitofrontal cortex, anterior cingulate cortex, middle cingulate cortex, thalamus, insular cortex, cerebellum, precuneus, gyrus rectus, subcallosal gyrus, middle temporal gyrus, fusiform gyrus and piriform cortex. No significant GM volume increase was detected in other brain areas. The pattern of GM atrophy was similar as previous literature reported. Our results identified similar GM volume alterations regardless of the causes of olfactory impairment. Decreased GM volume was not only shown in olfactory bulbs, olfactory tracts and olfactory sulcus, also in primary olfactory cortex and the secondary cerebral olfactory areas in ICA people. This is the first study to evaluate GM volume alterations in ICA people.

Do patients with rapid eye movement sleep behavior disorder have a disease-specific personality?

PubMed

Sasai, Taeko; Inoue, Yuichi; Matsuura, Masato

2012-06-01

Rapid eye movement sleep behavior disorder (RBD) occurs idiopathically (iRBD), frequently representing a prodromal phase of Parkinson's disease (PD). Previous reports have described that patients with PD have premorbid personality profiles such as industriousness, inflexibility, cautiousness, and lack of novelty seeking. As well, psychological stress often aggravates RBD symptoms. These phenomena encouraged us to investigate personality profiles in iRBD patients. In this study, 53 patients with iRBD and 49 age and sex-matched healthy controls (HC) were enrolled. We used the revised version of the NEO Personality Inventory (NEO-PIR) to measure the personality of these subjects, and the 5 domains and the 30 facets of the NEO-PIR were compared between the two groups. Within the iRBD group, we investigated the association between RBD variables, e.g. the proportion of REM sleep without atonia (RWA/REM), length of RBD morbidity, frequency of vocalization or abnormal behavior, and the variables of NEO-PIR. In the patients, olfactory function was significantly lower than that of healthy controls, but the inventory differences were not significant. The inventory showed no association with any RBD variable, or the existence of aggravation of these symptoms triggered by psychological stress, or olfactory dysfunction. These results suggest that RBD patients do not have a personality profile that might predict PD development. The personality profile itself cannot explain the psychological-stress-dependent aggravation of RBD symptoms. Copyright © 2011 Elsevier Ltd. All rights reserved.

An Olfactory Indicator for Acid-Base Titrations.

ERIC Educational Resources Information Center

Flair, Mark N.; Setzer, William N.

1990-01-01

The use of an olfactory acid-base indicator in titrations for visually impaired students is discussed. Potential olfactory indicators include eugenol, thymol, vanillin, and thiophenol. Titrations performed with each indicator with eugenol proved to be successful. (KR)

Acid-sensing ion channels in mouse olfactory bulb M/T neurons

PubMed Central

Li, Ming-Hua; Liu, Selina Qiuying; Inoue, Koichi; Lan, Jinquan; Simon, Roger P.

2014-01-01

The olfactory bulb contains the first synaptic relay in the olfactory pathway, the sensory system in which odorants are detected enabling these chemical stimuli to be transformed into electrical signals and, ultimately, the perception of odor. Acid-sensing ion channels (ASICs), a family of proton-gated cation channels, are widely expressed in neurons of the central nervous system. However, no direct electrophysiological and pharmacological characterizations of ASICs in olfactory bulb neurons have been described. Using a combination of whole-cell patch-clamp recordings and biochemical and molecular biological analyses, we demonstrated that functional ASICs exist in mouse olfactory bulb mitral/tufted (M/T) neurons and mainly consist of homomeric ASIC1a and heteromeric ASIC1a/2a channels. ASIC activation depolarized cultured M/T neurons and increased their intracellular calcium concentration. Thus, ASIC activation may play an important role in normal olfactory function. PMID:24821964

Olfactory Performance Is Predicted by Individual Sex-Atypicality, but Not Sexual Orientation

PubMed Central

Nováková, Lenka; Varella Valentová, Jaroslava; Havlíček, Jan

2013-01-01

Many previous studies have reported robust sex differences in olfactory perception. However, both men and women can be expected to vary in the degree to which they exhibit olfactory performance considered typical of their own or the opposite sex. Sex-atypicality is often described in terms of childhood gender nonconformity, which, however, is not a perfect correlate of non-heterosexual orientation. Here we explored intrasexual variability in psychophysical olfactory performance in a sample of 156 individuals (83 non-heterosexual) and found the lowest odor identification scores in heterosexual men. However, when childhood gender nonconformity was entered in the model along with sexual orientation, better odor identification scores were exhibited by gender-nonconforming men, and greater olfactory sensitivity by gender-conforming women, irrespective of their sexual orientation. Thus, sex-atypicality, but not sexual orientation predicts olfactory performance, and we propose that this might not be limited to olfaction, but represent a more general phenomenon. PMID:24244657

Ultrastructural characterisation of the olfactory mucosa of the armadillo Dasypus hybridus (Dasypodidae, Xenarthra)

PubMed Central

FERRARI, C. C.; CARMANCHAHI, P. D.; ALDANA MARCOS, H. J.; AFFANNI, J. M.

2000-01-01

The ultrastructure of the olfactory mucosa of the armadillo Dasypus hybridus was studied. A comparison with the olfactory mucosa of another armadillo (Chaetophractus villosus) was made. The olfactory mucosa of D. hybridus shows many features which are similar to those of other mammals. Interestingly, it differs from the olfactory mucosa of the armadillo C. villosus. A suggestion is made that these differences may be due to differences in the digging habits of these species. In Dasypus, the supporting cells (SCs) showed dense vacuoles, multivesicular bodies and lysosome-like bodies probably related with the endocytotic system. The SCs show a dense network of SER presumably associated with xenobiotic mechanisms. The olfactory receptor neurons exhibit lysosome-like bodies and multivesicular bodies in their perikarya. These organelles suggest the presence of an endocytotic system. Duct cells of Bowman's glands exhibit secretory activities. Bowman's glands are compound-branched tubulo-acinar mixed glands with merocrine secretory mechanisms. PMID:10739023

Nervus terminalis, olfactory nerve, and optic nerve representation of luteinizing hormone-releasing hormone in primates.

PubMed

Witkin, J W

1987-01-01

The luteinizing hormone-releasing hormone (LHRH) system was examined immunocytochemically in olfactory bulbs of adult monkeys, including two New World species (squirrel monkey, Saimiri sciureus and owl monkey, Aotus trivirgatus) and one Old World species (cynomolgus macaque, Macaca fasciculata), and in the brain and nasal region of a fetal rhesus macaque Macaca mulatta. LHRH neurons and fibers were found sparsely distributed in the olfactory bulbs in all adult monkeys. There was more LHRH in the accessory olfactory bulb (which is absent in Old World monkeys). In the fetal macaque there was a rich distribution of LHRH neurons and fibers along the pathway of the nervus terminalis, anterior and ventral to the olfactory bulb, and in the nasal septum, with fibers branching into the olfactory epithelium. In addition, there were LHRH neurons and fibers in the optic nerve.

Olfactory performance is predicted by individual sex-atypicality, but not sexual orientation.

PubMed

Nováková, Lenka; Varella Valentová, Jaroslava; Havlíček, Jan

2013-01-01

Many previous studies have reported robust sex differences in olfactory perception. However, both men and women can be expected to vary in the degree to which they exhibit olfactory performance considered typical of their own or the opposite sex. Sex-atypicality is often described in terms of childhood gender nonconformity, which, however, is not a perfect correlate of non-heterosexual orientation. Here we explored intrasexual variability in psychophysical olfactory performance in a sample of 156 individuals (83 non-heterosexual) and found the lowest odor identification scores in heterosexual men. However, when childhood gender nonconformity was entered in the model along with sexual orientation, better odor identification scores were exhibited by gender-nonconforming men, and greater olfactory sensitivity by gender-conforming women, irrespective of their sexual orientation. Thus, sex-atypicality, but not sexual orientation predicts olfactory performance, and we propose that this might not be limited to olfaction, but represent a more general phenomenon.

Specific olfactory receptor populations projecting to identified glomeruli in the rat olfactory bulb.

PubMed

Jastreboff, P J; Pedersen, P E; Greer, C A; Stewart, W B; Kauer, J S; Benson, T E; Shepherd, G M

1984-08-01

A critical gap exists in our knowledge of the topographical relationship between the olfactory epithelium and olfactory bulb. The present report describes the application to this problem of a method involving horseradish peroxidase conjugated to wheat germ agglutinin. This material was iontophoretically delivered to circumscribed glomeruli in the olfactory bulb and the characteristics and distribution of retrogradely labeled receptor cells were assessed. After discrete injections into small glomerular groups in the caudomedial bulb, topographically defined populations of receptor cells were labeled. Labeled receptor cell somata appeared at several levels within the epithelium. The receptor cell apical dendrites followed a tight helical course towards the surface of the epithelium. The data thus far demonstrate that functional units within the olfactory system may include not only glomeruli as previously suggested but, in addition, a corresponding matrix of receptor cells possessing functional and topographical specificity.

Specific olfactory receptor populations projecting to identified glomeruli in the rat olfactory bulb.

PubMed Central

Jastreboff, P J; Pedersen, P E; Greer, C A; Stewart, W B; Kauer, J S; Benson, T E; Shepherd, G M

1984-01-01

A critical gap exists in our knowledge of the topographical relationship between the olfactory epithelium and olfactory bulb. The present report describes the application to this problem of a method involving horseradish peroxidase conjugated to wheat germ agglutinin. This material was iontophoretically delivered to circumscribed glomeruli in the olfactory bulb and the characteristics and distribution of retrogradely labeled receptor cells were assessed. After discrete injections into small glomerular groups in the caudomedial bulb, topographically defined populations of receptor cells were labeled. Labeled receptor cell somata appeared at several levels within the epithelium. The receptor cell apical dendrites followed a tight helical course towards the surface of the epithelium. The data thus far demonstrate that functional units within the olfactory system may include not only glomeruli as previously suggested but, in addition, a corresponding matrix of receptor cells possessing functional and topographical specificity. Images PMID:6206495

Lateral presynaptic inhibition mediates gain control in an olfactory circuit.

PubMed

Olsen, Shawn R; Wilson, Rachel I

2008-04-24

Olfactory signals are transduced by a large family of odorant receptor proteins, each of which corresponds to a unique glomerulus in the first olfactory relay of the brain. Crosstalk between glomeruli has been proposed to be important in olfactory processing, but it is not clear how these interactions shape the odour responses of second-order neurons. In the Drosophila antennal lobe (a region analogous to the vertebrate olfactory bulb), we selectively removed most interglomerular input to genetically identified second-order olfactory neurons. Here we show that this broadens the odour tuning of these neurons, implying that interglomerular inhibition dominates over interglomerular excitation. The strength of this inhibitory signal scales with total feedforward input to the entire antennal lobe, and has similar tuning in different glomeruli. A substantial portion of this interglomerular inhibition acts at a presynaptic locus, and our results imply that this is mediated by both ionotropic and metabotropic receptors on the same nerve terminal.

Olfactory discrimination and memory deficits in the Flinders Sensitive Line rodent model of depression.

PubMed

Cook, A; Pfeiffer, L-M; Thiele, S; Coenen, V A; Döbrössy, M D

2017-10-01

Major Depressive Disorder (MDD) is a heterogeneous psychiatric disorder with broad symptomatic manifestations. The current study examined, for the first time, olfactory memory and discrimination in the Flinders Sensitive Line (FSL) rodent model of depression. Male FSL rats and controls were trained on an Olfactory Discrimination (OD) and a Social Interaction (SI) test. On the OD test, the FSL and controls performed similarly at the shortest inter-trial interval (5min), however, with extended delay of 30min, the FSLs had a recall and odour discrimination deficit. At the longest delay (60min) both groups performed poorly. The FSL rats i.) had a deficit in olfactory discrimination suggesting impairment in olfactory memory and recall; ii.) were less likely to socialize with unfamiliar rats. The data suggests that FSL animals have an impaired olfactory information processing capacity. Copyright © 2017 Elsevier B.V. All rights reserved.

Management of Parkinson׳s disease: Current and future pharmacotherapy.

PubMed

Kakkar, Ashish Kumar; Dahiya, Neha

2015-03-05

Parkinson׳s disease (PD) is chronic progressive neurodegenerative disorder characterized by profound loss of dopaminergic neurons in the nigrostriatal pathway. It is recognized by the cardinal clinical features of bradykinesia, rigidity, tremor and postural instability. Current therapeutic options are primarily dopamine replacement strategies that only provide symptomatic improvement without affecting progressive neuronal loss. These treatments often fail to provide sustained clinical benefit and most patients develop motor fluctuations and dyskinesias as the disease progresses. Additionally, non-motor symptoms such as autonomic disturbances, sensory alterations, olfactory dysfunction, mood disorders, sleep disturbances and cognitive impairment cause considerable functional disability in these patients and these features often fail to respond to standard dopaminergic treatments. This mini review outlines the current pharmacotherapeutic options for PD and highlights the emerging experimental therapies in various phases of clinical development. Copyright © 2015 Elsevier B.V. All rights reserved.

The olfactory gonadotropin-releasing hormone immunoreactive system in mouse.

PubMed

Jennes, L

1986-10-29

The olfactory gonadotropin-releasing hormone (GnRH) system in mice was studied with immunofluorescence in combination with lesions of the olfactory bulb and retrograde transport of horseradish peroxidase (HRP) which was administered intravascularly, intranasally or into the subarachnoid space. GnRH-positive neurons were located in the two major branches forming the septal roots of the nervus terminalis, in the ganglion terminale, within the fascicles of the nervus terminalis throughout its extent, in a conspicuous band which connects the ventral neck of the caudal olfactory bulb with the accessory olfactory bulb and in the nasal mucosa. GnRH-positive fibers were seen in all areas in which neurons were found, i.e. in the rostral septum, the ganglion and nervus terminalis and in the nasal subepithelium. In addition, a broad bundle of fibers was observed to surround the entire caudal olfactory bulb, connecting the rostral sulcus rhinalis with the ventrocaudal olfactory bulb. Fibers were seen in close association with the main and accessory olfactory bulb, with the fila olfactoria and with the nasal mucosa. Throughout the olfactory bulb and the nasal epithelium, an association of GnRH fibers with blood vessels was apparent. Intravascular and intranasal injection of HRP resulted in labeling of certain GnRH neurons in the septal roots of the nervus terminalis, the ganglion terminale, the nervus terminalis, the caudal ventrodorsal connection and in the accessory olfactory bulb. After placement of HRP into the subarachnoid space dorsal to the accessory olfactory bulb, about 50% of the GnRH neurons in the accessory olfactory bulb and in the ventrodorsal connection were labeled with HRP. Also, a few GnRH neurons in the rostral septum, the ganglion terminale and in the fascicles of the nervus terminalis had taken up the enzyme. Lesions of the nervus terminalis caudal to the ganglion terminale resulted in sprouting of GnRH fibers at both sites of the knife cut. Lesions rostral to the ganglion terminale induced sprouting mostly at the distal site of the knife cut while most but not all GnRH fibers proximal to the lesion had disappeared. The results of the present study indicate that the olfactory GnRH system is mostly associated with the nervus terminalis. This cranial nerve apparently projects to the central nervous system as well as the periphery. The results of the HRP uptake studies suggest that the GnRH neurons in the nervus terminalis have access to fenestrated capillaries in the subepithelial connective tissue of the nasal mucosa, to the nasal epithelium proper, and to the subarachnoid space.(ABSTRACT TRUNCATED AT 400 WORDS)

Odor-Induced Neuronal Rhythms in the Olfactory Bulb Are Profoundly Modified in ob/ob Obese Mice

PubMed Central

Chelminski, Yan; Magnan, Christophe; Luquet, Serge H.; Everard, Amandine; Meunier, Nicolas; Gurden, Hirac; Martin, Claire

2017-01-01

Leptin, the product of the Ob(Lep) gene, is a peptide hormone that plays a major role in maintaining the balance between food intake and energy expenditure. In the brain, leptin receptors are expressed by hypothalamic cells but also in the olfactory bulb, the first central structure coding for odors, suggesting a precise function of this hormone in odor-evoked activities. Although olfaction plays a key role in feeding behavior, the ability of the olfactory bulb to integrate the energy-related signal leptin is still missing. Therefore, we studied the fate of odor-induced activity in the olfactory bulb in the genetic context of leptin deficiency using the obese ob/ob mice. By means of an odor discrimination task with concomitant local field potential recordings, we showed that ob/ob mice perform better than wild-type (WT) mice in the early stage of the task. This behavioral gain of function was associated in parallel with profound changes in neuronal oscillations in the olfactory bulb. The distribution of the peaks in the gamma frequency range was shifted toward higher frequencies in ob/ob mice compared to WT mice before learning. More notably, beta oscillatory activity, which has been shown previously to be correlated with olfactory discrimination learning, was longer and stronger in expert ob/ob mice after learning. Since oscillations in the olfactory bulb emerge from mitral to granule cell interactions, our results suggest that cellular dynamics in the olfactory bulb are deeply modified in ob/ob mice in the context of olfactory learning. PMID:28154537

Ultrastructural study of the primary olfactory pathway in Macaca fascicularis.

PubMed

Herrera, Loren P; Casas, Carlos E; Bates, Margaret L; Guest, James D

2005-08-08

Olfactory ensheathing glial cells (OEGs) interact with a wide repertoire of cell types and support extension of olfactory axons (OAs) within the olfactory pathway. OEGs are thought to exclude OAs from contact with all other cells between the olfactory epithelium and the glomerulus of the olfactory bulb. These properties have lead to testing to determine whether OEGs support axonal growth following transplantation. The cellular interactions of transplanted OEGs will probably resemble those that occur within the normal pathway where interactions between OEGs and fibroblasts are prominent. No previous primate studies have focused on these interactions, knowledge of which is important if clinical application is envisioned. We describe the detailed intercellular interactions of OAs with supporting cells throughout the olfactory epithelium, the lamina propria, the fila olfactoria, and the olfactory nerve layer by using transmission electron microscopy in adult Macaca fascicularis. Patterns of OEG ensheathment and variations of the endo- and perineurium formed by olfactory nerve fibroblasts are described. OAs mainly interacted with horizontal basal cells, OEGs, and astrocytes. At both transitional ends of the pathway seamless intercellular interactions were observed, and fibroblast processes were absent. Perineurial cells produced surface basal lamina; however, endoneurial, epineurial, and meningeal fibroblasts did not. Perineurial cells contained intermediate filaments and were distinct from other fibroblasts and meningeal cells. OAs had direct contacts with astrocytes near the glia limitans. The properties of OEGs differed depending on whether astrocytic or fibroblastic processes were present. This indicates the importance of the cellular milieu in the structure and function of OEGs in primates.

In vivo bioelectronic nose using transgenic mice for specific odor detection.

PubMed

Gao, Keqiang; Li, Songmin; Zhuang, Liujing; Qin, Zhen; Zhang, Bin; Huang, Liquan; Wang, Ping

2018-04-15

The olfactory system is a natural biosensor since its peripheral olfactory sensory neurons (OSNs) respond to the external stimuli and transmit the signals to the olfactory bulb (OB) where they are integrated and processed. The axonal connections from the OSNs expressing about 1000 different types of odorant receptors are precisely organized and sorted out onto 1800 glomeruli in the OB, from which the olfactory information is delivered to and perceived by the central nervous system. This process is carried out with particularly high sensitivity, specificity and rapidity, which can be used for explosive detection. Biomimetic olfactory biosensors use various biological components from the olfactory system as sensing elements, possessing great commercial prospects. In this study, we utilized the genetically labeled murine M72 olfactory sensory neurons with the green fluorescent protein (GFP) as sensing components and obtained long-term in vivo electrophysiological recordings from the M72 OSNs by implanting the microelectrode arrays (MEAs) into the behaving mouse's OB. The electrophysiological responses showed high reliability, reproducibility and specificity for odor detection, and particularly, the high sensitivity for the detection of odorants that contain benzene rings. Furthermore, our results indicated that it can detect trinitrotoluene (TNT) in liquid at a concentration as low as 10 -5 M and can distinguish TNT from other chemicals with a similar structure. Thus our study demonstrated that the in vivo biomimetic olfactory system could provide novel approaches to enhancing the specificity and increasing working lifespan of olfactory biosensors capable of detecting explosives. Copyright © 2017 Elsevier B.V. All rights reserved.

Reference values of olfactory function for Mexico City inhabitants.

PubMed

Guarneros, Marco; Hudson, Robyn; López-Palacios, Martha; Drucker-Colín, René

2015-01-01

Olfactory testing is useful in the differential diagnosis of age-related pathologies. To provide baseline reference values for clinical use in Mexico City we investigated the relation between olfactory capabilities and the principal population parameters of age, sex, and smoking habits in a large sample of healthy inhabitants. We applied the internationally recognized and commercially available Sniffin' Sticks test battery to 916 men and women from across the adult life span. The Sniffin' Sticks test evaluates three key aspects of olfactory function: 1) ability to detect an odor, 2) to discriminate between odors, and 3) to identify odors. We found a significant decline in olfactory function from the 5th decade of age, and that detection threshold was the most sensitive measure of this. We did not find a significant difference between men and women or between smokers and non-smokers. In confirmation of our previous studies of the negative effect of air pollution on olfactory function, Mexico City inhabitants had poorer overall performance than corresponding subjects previously tested in the neighboring but less polluted Mexican state of Tlaxcala. Although we basically confirm findings on general demographic patterns of olfactory performance from other countries, we also demonstrate the need to take into account local cultural, environmental and demographic factors in the clinical evaluation of olfactory performance of Mexico City inhabitants. The Sniffin' Sticks test battery, with some adjustment of stimuli to correspond to Mexican culture, provides an easily administered means of assessing olfactory health. Copyright © 2015 IMSS. Published by Elsevier Inc. All rights reserved.

Time frequency analysis of olfactory induced EEG-power change.

PubMed

Schriever, Valentin Alexander; Han, Pengfei; Weise, Stefanie; Hösel, Franziska; Pellegrino, Robert; Hummel, Thomas

2017-01-01

The objective of the present study was to investigate the usefulness of time-frequency analysis (TFA) of olfactory-induced EEG change with a low-cost, portable olfactometer in the clinical investigation of smell function. A total of 78 volunteers participated. The study was composed of three parts where olfactory stimuli were presented using a custom-built olfactometer. Part I was designed to optimize the stimulus as well as the recording conditions. In part II EEG-power changes after olfactory/trigeminal stimulation were compared between healthy participants and patients with olfactory impairment. In Part III the test-retest reliability of the method was evaluated in healthy subjects. Part I indicated that the most effective paradigm for stimulus presentation was cued stimulus, with an interstimulus interval of 18-20s at a stimulus duration of 1000ms with each stimulus quality presented 60 times in blocks of 20 stimuli each. In Part II we found that central processing of olfactory stimuli analyzed by TFA differed significantly between healthy controls and patients even when controlling for age. It was possible to reliably distinguish patients with olfactory impairment from healthy individuals at a high degree of accuracy (healthy controls vs anosmic patients: sensitivity 75%; specificity 89%). In addition we could show a good test-retest reliability of TFA of chemosensory induced EEG-power changes in Part III. Central processing of olfactory stimuli analyzed by TFA reliably distinguishes patients with olfactory impairment from healthy individuals at a high degree of accuracy. Importantly this can be achieved with a simple olfactometer.

Retinoic Acid Is Present in the Postnatal Rat Olfactory Organ and Persists in Vitamin A–Depleted Neural Tissue1–3

PubMed Central

Asson-Batres, Mary Ann; Smith, W. Bradford; Clark, Gale

2009-01-01

Vitamin A (VA), all-trans-retinol (at-ROL), and its derivative, all-trans-retinoic acid (at-RA), are required for neuron development. The effects of these retinoids are dependent upon the nutritional status of the rat and tissue-specific dynamics of retinoid access and utilization. The purpose of this study was to determine the status of at-ROL and at-RA in the peripheral olfactory organ of postnatal rats fed a normal diet and rats fed a VA-deficient (VAD) diet. Extracted retinoids were analyzed by HPLC. Resolved sample peaks were identified by comparing their elution times and spectra with those of authentic standards. Mean at-RA and at-ROL concentrations of 23 pmol/g olfactory tissue and 0.13 nmol/g, respectively, were recovered from olfactory tissue. The ratio of at-RA:at-ROL in olfactory was ∼2 times that in testis and 200 times that in liver. at-ROL was depleted from the liver and olfactory organ of rats fed a VAD diet from birth to 70 d of age. Surprisingly, at-RA was still present in olfactory tissue from these rats. At 90 d of age, the VAD rats were frankly deficient and at-RA was no longer detectable in olfactory tissue. The comparatively high ratio of at-RA:at-ROL in the peripheral olfactory organ and the persistence of at-RA in at-ROL-depleted tissues strongly suggests that maintenance of local stores of at-RA is functionally relevant in this tissue. PMID:19403718

Integrating temperature with odor processing in the olfactory bulb.

PubMed

Kludt, Eugen; Okom, Camille; Brinkmann, Alexander; Schild, Detlev

2015-05-20

Temperature perception has long been classified as a somesthetic function solely. However, in recent years several studies brought evidence that temperature perception also takes place in the olfactory system of rodents. Temperature has been described as an effective stimulus for sensory neurons of the Grueneberg ganglion located at the entrance of the nose. Here, we investigate whether a neuronal trace of temperature stimulation can be observed in the glomeruli and mitral cells of the olfactory bulb, using calcium imaging and fast line-scanning microscopy. We show in the Xenopus tadpole system that the γ-glomerulus, which receives input from olfactory neurons, is highly sensitive to temperature drops at the olfactory epithelium. We observed that thermo-induced activity in the γ-glomerulus is conveyed to the mitral cells innervating this specific neuropil. Surprisingly, a substantial number of thermosensitive mitral cells were also chemosensitive. Moreover, we report another unique feature of the γ-glomerulus: it receives ipsilateral and contralateral afferents. The latter fibers pass through the contralateral bulb, cross the anterior commissure, and then run to the ipsilateral olfactory bulb, where they target the γ-glomerulus. Temperature drops at the contralateral olfactory epithelium also induced responses in the γ-glomerulus and in mitral cells. Temperature thus appears to be a relevant physiological input to the Xenopus olfactory system. Each olfactory bulb integrates and codes temperature signals originating from receptor neurons of the ipsilateral and contralateral nasal cavities. Finally, temperature and chemical information is processed in shared cellular networks. Copyright © 2015 the authors 0270-6474/15/357892-11$15.00/0.

Behavioral and Neurophysiological Study of Olfactory Perception and Learning in Honeybees

PubMed Central

Sandoz, Jean Christophe

2011-01-01

The honeybee Apis mellifera has been a central insect model in the study of olfactory perception and learning for more than a century, starting with pioneer work by Karl von Frisch. Research on olfaction in honeybees has greatly benefited from the advent of a range of behavioral and neurophysiological paradigms in the Lab. Here I review major findings about how the honeybee brain detects, processes, and learns odors, based on behavioral, neuroanatomical, and neurophysiological approaches. I first address the behavioral study of olfactory learning, from experiments on free-flying workers visiting artificial flowers to laboratory-based conditioning protocols on restrained individuals. I explain how the study of olfactory learning has allowed understanding the discrimination and generalization ability of the honeybee olfactory system, its capacity to grant special properties to olfactory mixtures as well as to retain individual component information. Next, based on the impressive amount of anatomical and immunochemical studies of the bee brain, I detail our knowledge of olfactory pathways. I then show how functional recordings of odor-evoked activity in the brain allow following the transformation of the olfactory message from the periphery until higher-order central structures. Data from extra- and intracellular electrophysiological approaches as well as from the most recent optical imaging developments are described. Lastly, I discuss results addressing how odor representation changes as a result of experience. This impressive ensemble of behavioral, neuroanatomical, and neurophysiological data available in the bee make it an attractive model for future research aiming to understand olfactory perception and learning in an integrative fashion. PMID:22163215

Effect of strong fragrance on olfactory detection threshold.

PubMed

Fasunla, Ayotunde James; Douglas, David Dayo; Adeosun, Aderemi Adeleke; Steinbach, Silke; Nwaorgu, Onyekwere George Benjamin

2014-09-01

To assess the olfactory threshold of healthy volunteers at the University College Hospital, Ibadan and to investigate the effect of perfume on their olfactory detection thresholds. A quasi-experimental study on olfactory detection thresholds of healthy volunteers from September 2013 to November 2013. Tertiary health institution. A structured questionniare was administered to the participants in order to obtain information on sociodemographics, occupation, ability to perceive smell, use of perfume, effects of perfume on appetite and self-confidence, history of allergy, and previous nasal surgery. Participants subjectively rated their olfactory performance. Subsequently, they had olfactory detection threshold testing done at baseline and after exposure to perfume with varied concentrations of n-butanol in a forced triple response and staircase fashion. Healthy volunteers, 37 males and 63 females, were evaluated. Their ages ranged from 19 to 59 years with a mean of 31 years ± 8. Subjectively, 94% of the participants had excellent olfactory function. In the pre-exposure forced triple response, 88% were able to detect the odor at ≤.25 mmol/l concentration while in the post-exposure forced triple response, only 66% were able to detect the odor at ≤.25 mmol/l concentration. There is also a statistical significant difference in the olfactory detection threshold score between the pre-exposure and post-exposure period in the participants (P < .05). Use of strong fragrances affects the olfactory detection threshold. Therefore patients and clinicians should be aware of this and its effects on the outcome of test of olfaction. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

On the olfactory anatomy in an archaic whale (Protocetidae, Cetacea) and the minke whale Balaenoptera acutorostrata (Balaenopteridae, Cetacea).

PubMed

Godfrey, Stephen J; Geisler, Jonathan; Fitzgerald, Erich M G

2013-02-01

The structure of the olfactory apparatus is not well known in both archaic and extant whales; the result of poor preservation in most fossils and locational isolation deep within the skulls in both fossil and Recent taxa. Several specimens now shed additional light on the subject. A partial skull of an archaic cetacean is reported from the Pamunkey River, Virginia, USA. The specimen probably derives from the upper middle Eocene (Piney Point Formation) and is tentatively assigned to the Protocetidae. Uncrushed cranial cavities associated with the olfactory apparatus were devoid of sediment. CT scans clearly reveal the dorsal nasal meatus, ethmoturbinates within the olfactory recess, the cribriform plate, the area occupied by the olfactory bulbs, and the olfactory nerve tract. Several sectioned skulls of the minke whale (Balaenoptera acutorostrata) were also examined, and olfactory structures are remarkably similar to those observed in the fossil skull from the Pamunkey River. One important difference between the two is that the fossil specimen has an elongate olfactory nerve tract. The more forward position of the external nares in extant balaenopterids when compared with those of extant odontocetes is interpreted to be the result of the need to retain a functional olfactory apparatus and the forward position of the supraoccipital/cranial vertex. An increase in the distance between the occipital condyles and the vertex in balaenopterids enhances the mechanical advantage of the epaxial musculature that inserts on the occiput, a specialization that likely stabilizes the head of these enormous mammals during lunge feeding. Copyright © 2012 Wiley Periodicals, Inc.

Parallel processing via a dual olfactory pathway in the honeybee.

PubMed

Brill, Martin F; Rosenbaum, Tobias; Reus, Isabelle; Kleineidam, Christoph J; Nawrot, Martin P; Rössler, Wolfgang

2013-02-06

In their natural environment, animals face complex and highly dynamic olfactory input. Thus vertebrates as well as invertebrates require fast and reliable processing of olfactory information. Parallel processing has been shown to improve processing speed and power in other sensory systems and is characterized by extraction of different stimulus parameters along parallel sensory information streams. Honeybees possess an elaborate olfactory system with unique neuronal architecture: a dual olfactory pathway comprising a medial projection-neuron (PN) antennal lobe (AL) protocerebral output tract (m-APT) and a lateral PN AL output tract (l-APT) connecting the olfactory lobes with higher-order brain centers. We asked whether this neuronal architecture serves parallel processing and employed a novel technique for simultaneous multiunit recordings from both tracts. The results revealed response profiles from a high number of PNs of both tracts to floral, pheromonal, and biologically relevant odor mixtures tested over multiple trials. PNs from both tracts responded to all tested odors, but with different characteristics indicating parallel processing of similar odors. Both PN tracts were activated by widely overlapping response profiles, which is a requirement for parallel processing. The l-APT PNs had broad response profiles suggesting generalized coding properties, whereas the responses of m-APT PNs were comparatively weaker and less frequent, indicating higher odor specificity. Comparison of response latencies within and across tracts revealed odor-dependent latencies. We suggest that parallel processing via the honeybee dual olfactory pathway provides enhanced odor processing capabilities serving sophisticated odor perception and olfactory demands associated with a complex olfactory world of this social insect.

Determinants of human olfactory performance: a cross-cultural study.

PubMed

Sorokowska, Agnieszka; Sorokowski, Piotr; Frackowiak, Tomasz

2015-02-15

Olfaction allows us to detect subtle changes in our environment, but sensitivity of the sense of smell varies among individuals. Although a significant number of research papers discuss the relationship between olfactory abilities and environmental factors, most studies have been conducted on Western populations or in developed Asian societies. The potential environmental and cultural determinants of olfactory acuity warrant further exploration. In the current study, we compared previously published data on olfaction in an industrialized, modern society (i.e., Europeans) and an indigenous society living in unpolluted, natural environmental conditions (i.e., Tsimane'), with novel data on the olfactory acuity of inhabitants of the Cook Islands. Like the European population (and contrary to the Tsimane'), the Cook Islands people form a modern society, and like the Tsimane' population (and contrary to the Europeans), they live in an unpolluted region. Thus, these comparisons enabled us to independently assess the importance of both air pollution and changes in lifestyle for olfactory abilities in modern societies. Our results indicate that people from the Cook Islands had significantly higher olfactory acuity (i.e., lower thresholds of odor detection) than did Europeans and Tsimane' people. Interestingly, the olfactory sensitivity of Europeans was significantly lower than the olfactory sensitivity of the remaining two groups. Our data suggest that air pollution is an important factor in the deterioration of the sense of smell. However, it is also possible that factors such as agricultural and/or cooking practices, alcohol consumption, and access to medical service may also influence olfactory acuity. Copyright © 2014 Elsevier B.V. All rights reserved.

[Evaluating function and disorders of smell].

PubMed

Herberhold, C

1975-01-01

Firstly the review deals with the olfactometry after discussing the olfactory and trigeminal sensitivity of the sense of smell. The term olfactometry will be newly fixed concerning the present problems of odor analysis. Under clinical aspects the methods of subjective olfactometry are discussed and valued. Olfactory tests basing on registering several psychosomatic reflexes (e.g. cardial and/or respiratory frequencies) cannot be described as "objective". Rather methods are objective which record poststimulatory electrophysiological events at different steps of olfactory pathways. The electric response olfactometry representing a cortical evoked so-called twin-potential containing equivalents for trigeminal and olfactory sense activity starts to demonstrate its efficiency. At least a complete test of olfactory function today includes the rhinomanometry for recording ability in nasal odor transport capacity. In the second part are discussed the olfactory disorders with clinical importance. Air borne disorders are confronted with sensorineural, which again are divided in prebulbar, bulbar, and postbulbar ones so far as possible. Respiratory smell disorders depend on nasal ventilation and occur in nasal deformations, in abnormalities of respiratory pathways, in cases of foreign bodies, mucosal inflammations, tumors, intoxications and allergy. Sensorineural olfactory disorders can be attached to age, to malformations or idiopathic defects, inflammations of the olfactory-neural apparatus, head injuries, brain tumors, metabolic or endocrinological diseases. Furthermore often they are accompanied with neurological and psychiatric diseases or professional and chemical intoxications and/or iatrogenic influences. The poor therapeutical possibilities are demonstrated as far as possible. Finally the experting problems in olfactory disorders are delineated, at which the evidence of objective olfactometry can be distincted.

Dilation of the olfactory bulb cavity concurrent with hydrocephalus in four small breed dogs

PubMed Central

Kim, Jung-Hyun; Jeon, Hyo-Won; Woo, Eung-Je

2009-01-01

Four small breed dogs were admitted with seizures. Magnetic resonance imaging (MRI) of the brain revealed dilation of the olfactory bulb cavity as well as enlargement of the lateral ventricles. These findings demonstrate that dilation of the olfactory bulb cavity can occur concurrent with hydrocephalus. This is the first description of the clinical and MRI features of dilation of the olfactory bulb cavity concurrent with hydrocephalus in dogs. PMID:19461216

The sox gene Dichaete is expressed in local interneurons and functions in development of the Drosophila adult olfactory circuit.

PubMed

Melnattur, Krishna V; Berdnik, Daniela; Rusan, Zeid; Ferreira, Christopher J; Nambu, John R

2013-02-01

In insects, the primary sites of integration for olfactory sensory input are the glomeruli in the antennal lobes. Here, axons of olfactory receptor neurons synapse with dendrites of the projection neurons that relay olfactory input to higher brain centers, such as the mushroom bodies and lateral horn. Interactions between olfactory receptor neurons and projection neurons are modulated by excitatory and inhibitory input from a group of local interneurons. While significant insight has been gleaned into the differentiation of olfactory receptor and projection neurons, much less is known about the development and function of the local interneurons. We have found that Dichaete, a conserved Sox HMG box gene, is strongly expressed in a cluster of LAAL cells located adjacent to each antennal lobe in the adult brain. Within these clusters, Dichaete protein expression is detected in both cholinergic and GABAergic local interneurons. In contrast, Dichaete expression is not detected in mature or developing projection neurons, or developing olfactory receptor neurons. Analysis of novel viable Dichaete mutant alleles revealed misrouting of specific projection neuron dendrites and axons, and alterations in glomeruli organization. These results suggest noncell autonomous functions of Dichaete in projection neuron differentiation as well as a potential role for Dichaete-expressing local interneurons in development of the adult olfactory circuitry. Copyright © 2012 Wiley Periodicals, Inc.

[Odor sensing system and olfactory display].

PubMed

Nakamoto, Takamichi

2014-01-01

In this review, an odor sensing system and an olfactory display are introduced into people in pharmacy. An odor sensing system consists of an array of sensors with partially overlapping specificities and pattern recognition technique. One of examples of odor sensing systems is a halitosis sensor which quantifies the mixture composition of three volatile sulfide compounds. A halitosis sensor was realized using a preconcentrator to raise sensitivity and an electrochemical sensor array to suppress the influence of humidity. Partial least squares (PLS) method was used to quantify the mixture composition. The experiment reveals that the sufficient accuracy was obtained. Moreover, the olfactory display, which present scents to human noses, is explained. A multi-component olfactory display enables the presentation of a variety of smells. The two types of multi-component olfactory display are described. The first one uses many solenoid valves with high speed switching. The valve ON frequency determines the concentration of the corresponding odor component. The latter one consists of miniaturized liquid pumps and a surface acoustic wave (SAW) atomizer. It enables the wearable olfactory display without smell persistence. Finally, the application of the olfactory display is demonstrated. Virtual ice cream shop with scents was made as a content of interactive art. People can enjoy harmony among vision, audition and olfaction. In conclusion, both odor sensing system and olfactory display can contribute to the field of human health care.

Parallel processing of afferent olfactory sensory information

PubMed Central

Vaaga, Christopher E.

2016-01-01

Key points The functional synaptic connectivity between olfactory receptor neurons and principal cells within the olfactory bulb is not well understood.One view suggests that mitral cells, the primary output neuron of the olfactory bulb, are solely activated by feedforward excitation.Using focal, single glomerular stimulation, we demonstrate that mitral cells receive direct, monosynaptic input from olfactory receptor neurons.Compared to external tufted cells, mitral cells have a prolonged afferent‐evoked EPSC, which serves to amplify the synaptic input.The properties of presynaptic glutamate release from olfactory receptor neurons are similar between mitral and external tufted cells.Our data suggest that afferent input enters the olfactory bulb in a parallel fashion. Abstract Primary olfactory receptor neurons terminate in anatomically and functionally discrete cortical modules known as olfactory bulb glomeruli. The synaptic connectivity and postsynaptic responses of mitral and external tufted cells within the glomerulus may involve both direct and indirect components. For example, it has been suggested that sensory input to mitral cells is indirect through feedforward excitation from external tufted cells. We also observed feedforward excitation of mitral cells with weak stimulation of the olfactory nerve layer; however, focal stimulation of an axon bundle entering an individual glomerulus revealed that mitral cells receive monosynaptic afferent inputs. Although external tufted cells had a 4.1‐fold larger peak EPSC amplitude, integration of the evoked currents showed that the synaptic charge was 5‐fold larger in mitral cells, reflecting the prolonged response in mitral cells. Presynaptic afferents onto mitral and external tufted cells had similar quantal amplitude and release probability, suggesting that the larger peak EPSC in external tufted cells was the result of more synaptic contacts. The results of the present study indicate that the monosynaptic afferent input to mitral cells depends on the strength of odorant stimulation. The enhanced spiking that we observed in response to brief afferent input provides a mechanism for amplifying sensory information and contrasts with the transient response in external tufted cells. These parallel input paths may have discrete functions in processing olfactory sensory input. PMID:27377344

Cilia- and Flagella-Associated Protein 69 Regulates Olfactory Transduction Kinetics in Mice

PubMed Central

Dong, Frederick N.

2017-01-01

Animals detect odorous chemicals through specialized olfactory sensory neurons (OSNs) that transduce odorants into neural electrical signals. We identified a novel and evolutionarily conserved protein, cilia- and flagella-associated protein 69 (CFAP69), in mice that regulates olfactory transduction kinetics. In the olfactory epithelium, CFAP69 is enriched in OSN cilia, where olfactory transduction occurs. Bioinformatic analysis suggests that a large portion of CFAP69 can form Armadillo-type α-helical repeats, which may mediate protein–protein interactions. OSNs lacking CFAP69, remarkably, displayed faster kinetics in both the on and off phases of electrophysiological responses at both the neuronal ensemble level as observed by electroolfactogram and the single-cell level as observed by single-cell suction pipette recordings. In single-cell analysis, OSNs lacking CFAP69 showed faster response integration and were able to fire APs more faithfully to repeated odor stimuli. Furthermore, both male and female mutant mice that specifically lack CFAP69 in OSNs exhibited attenuated performance in a buried food pellet test when a background of the same odor to the food pellet was present even though they should have better temporal resolution of coding olfactory stimulation at the peripheral. Therefore, the role of CFAP69 in the olfactory system seems to be to allow the olfactory transduction machinery to work at a precisely regulated range of response kinetics for robust olfactory behavior. SIGNIFICANCE STATEMENT Sensory receptor cells are generally thought to evolve to respond to sensory cues as fast as they can. This idea is consistent with mutational analyses in various sensory systems, where mutations of sensory receptor cells often resulted in reduced response size and slowed response kinetics. Contrary to this idea, we have found that there is a kinetic “damper” present in the olfactory transduction cascade of the mouse that slows down the response kinetics and, by doing so, it reduces the peripheral temporal resolution in coding odor stimuli and allows for robust olfactory behavior. This study should trigger a rethinking of the significance of the intrinsic speed of sensory transduction and the pattern of the peripheral coding of sensory stimuli. PMID:28495971

Protectiveness of water quality criteria for copper in western United States waters relative to predicted olfactory responses in juvenile Pacific salmon.

PubMed

DeForest, David K; Gensemer, Robert W; Van Genderen, Eric J; Gorsuch, Joseph W

2011-07-01

Copper (Cu) can impair olfaction in juvenile Pacific salmon (as well as other fishes), thus potentially inhibiting the ability of juveniles to avoid predators or to find food. Because Cu is commonly elevated in stormwater runoff in urban environments, storm events may result in elevated Cu concentrations in salmon-bearing streams. Accordingly, there is concern that existing Cu criteria, which were not derived using data for olfactory-related endpoints, may not be adequately protective of juvenile salmon. However, a modification of the US Environmental Protection Agency (USEPA) biotic ligand model (BLM) for deriving site-specific Cu criteria was recently proposed, which accounted for the sensitivity of olfactory endpoints. The modification was based on olfactory inhibition in juvenile coho salmon (Oncorhynchus kisutch) exposed to Cu in various combinations of pH, hardness, alkalinity, and dissolved organic carbon (DOC) concentrations. We used that olfactory-based BLM to derive 20% inhibition concentrations (IC20) values for Cu for 133 stream locations in the western United States. The olfactory BLM-based IC20 values were compared to the existing hardness-based Cu criteria and the USEPA's BLM-based Cu criteria for these representative natural waters of the western United States. Of the 133 sampling locations, mean hardness-dependent acute and chronic Cu criteria were below the mean olfactory-based BLM IC20 value in 122 (92%) and 129 (97%) of the waters, respectively (i.e., <20% olfactory impairment would have been predicted at the mean hardness-based Cu criteria concentrations). Waters characterized by a combination of high hardness and very low DOC were most likely to have hardness-based Cu criteria that were higher than the olfactory-based BLM IC20 values, because DOC strongly influences Cu bioavailability in the BLM. In all waters, the USEPA's current BLM-based criteria were below the mean olfactory-based BLM IC20 values, indicating that the USEPA's BLM-based criteria are protective of olfactory impairment in juvenile salmon. Copyright © 2011 SETAC.

Developmental Markers Expressed in Neocortical Layers Are Differentially Exhibited in Olfactory Cortex

PubMed Central

Brunjes, Peter C.; Osterberg, Stephen K.

2015-01-01

Neurons in the cerebral cortex stratify on the basis of their time of origin, axonal terminations and the molecular identities assigned during early development. Olfactory cortices share many feature with the neocortex, including clear lamination and similar cell types. The present study demonstrates that the markers differentially expressed in the projection neurons of the cerebral cortex are also found in olfactory areas. Three of the four regions examined (pars principalis of the anterior olfactory nucleus: AONpP, anterior and posterior piriform cortices: APC, PPC, and the olfactory tubercle) expressed transcription factors found in deep or superficial neurons in the developing neocortex, though large differences were found between areas. For example, while the AONpP, APC and PPC all broadly expressed the deep cortical marker CTIP2, NOR1 (NR4a3) levels were higher in AONpP and DAARP-32 was more prevalent in the APC and PPC. Similar findings were encountered for superficial cortical markers: all three regions broadly expressed CUX1, but CART was only observed in the APC and PPC. Furthermore, regional variations were observed even within single structures (e.g., NOR1 was found primarily in in the dorsal region of AONpP and CART expression was observed in a discrete band in the middle of layer 2 of both the APC and PPC). Experiments using the mitotic marker EDU verified that the olfactory cortices and neocortex share similar patterns of neuronal production: olfactory cells that express markers found in the deep neocortex are produced earlier than those that express superficial makers. Projection neurons were filled by retrograde tracers injected into the olfactory bulb to see if olfactory neurons with deep and superficial markers had different axonal targets. Unlike the cerebral cortex, no specificity was observed: neurons with each of the transcription factors examined were found to be labelled. Together the results indicate that olfactory cortices are complex: they differ from each other and each is formed from a variable mosaic of neurons. The results suggest that the olfactory cortices are not merely a remnant architype of the primordial forebrain but varied and independent regions. PMID:26407299

Cognitive findings after transient global amnesia: role of prefrontal cortex.

PubMed

Le Pira, Francesco; Giuffrida, Salvatore; Maci, Tiziana; Reggio, Ester; Zappalà, Giuseppe; Perciavalle, Vincenzo

2005-01-01

The aim of this study is to verify, after recovery, the presence of specific patterns of cognitive dysfunctions in Transient Global Amnesia (TGA). Fourteen patients with the diagnosis of TGA were submitted to a battery of neuropsychological tests and compared to a matched control group. We found significant qualitative and quantitative differences between TGA patients and controls in the California Verbal Learning Test (CLVT) and Rey-Osterrieth Complex Figure Test. Our data support the presence of selective cognitive dysfunctions after the clinical recovery. Moreover, for Verbal Fluency, Digit Span Backward, and Number of Clusters in the CVLT short-term memory test, the relation resulted as positively related with the temporal interval from the TGA episode. Reduction of categorical learning, attention, and qualitative alterations of spatial strategy seem to postulate a planning defect due to a prefrontal impairment.

Ultrastructural localization of connexins (Cx36, Cx43, Cx45), glutamate receptors and aquaporin-4 in rodent olfactory mucosa, olfactory nerve and olfactory bulb

PubMed Central

RASH, JOHN E.; DAVIDSON, KIMBERLY G. V.; KAMASAWA, NAOMI; YASUMURA, THOMAS; KAMASAWA, MASAMI; ZHANG, CHUNBO; MICHAELS, ROBIN; RESTREPO, DIEGO; OTTERSEN, OLE P.; OLSON, CARL O.; NAGY, JAMES I.

2006-01-01

Odorant/receptor binding and initial olfactory information processing occurs in olfactory receptor neurons (ORNs) within the olfactory epithelium. Subsequent information coding involves high-frequency spike synchronization of paired mitral/tufted cell dendrites within olfactory bulb (OB) glomeruli via positive feedback between glutamate receptors and closely-associated gap junctions. With mRNA for connexins Cx36, Cx43 and Cx45 detected within ORN somata and Cx36 and Cx43 proteins reported in ORN somata and axons, abundant gap junctions were proposed to couple ORNs. We used freeze-fracture replica immunogold labeling (FRIL) and confocal immunofluorescence microscopy to examine Cx36, Cx43 and Cx45 protein in gap junctions in olfactory mucosa, olfactory nerve and OB in adult rats and mice and early postnatal rats. In olfactory mucosa, Cx43 was detected in gap junctions between virtually all intrinsic cell types except ORNs and basal cells; whereas Cx45 was restricted to gap junctions in sustentacular cells. ORN axons contained neither gap junctions nor any of the three connexins. In OB, Cx43 was detected in homologous gap junctions between almost all cell types except neurons and oligodendrocytes. Cx36 and, less abundantly, Cx45 were present in neuronal gap junctions, primarily at “mixed” glutamatergic/electrical synapses between presumptive mitral/tufted cell dendrites. Genomic analysis revealed multiple miRNA (micro interfering RNA) binding sequences in 3′-untranslated regions of Cx36, Cx43 and Cx45 genes, consistent with cell-type-specific post-transcriptional regulation of connexin synthesis. Our data confirm absence of gap junctions between ORNs, and support Cx36- and Cx45-containing gap junctions at glutamatergic mixed synapses between mitral/tufted cells as contributing to higher-order information coding within OB glomeruli. PMID:16841170

Relationships between pathologic subjective halitosis, olfactory reference syndrome, and social anxiety in young Japanese women.

PubMed

Tsuruta, Miho; Takahashi, Toru; Tokunaga, Miki; Iwasaki, Masanori; Kataoka, Shota; Kakuta, Satoko; Soh, Inho; Awano, Shuji; Hirata, Hiromi; Kagawa, Masaharu; Ansai, Toshihiro

2017-03-14

Pathologic subjective halitosis is known as a halitosis complaint without objective confirmation of halitosis by others or by halitometer measurements; it has been reported to be associated with social anxiety disorder. Olfactory reference syndrome is a preoccupation with the false belief that one emits a foul and offensive body odor. Generally, patients with olfactory reference syndrome are concerned with multiple body parts. However, the mouth is known to be the most common source of body odor for those with olfactory reference syndrome, which could imply that the two conditions share similar features. Therefore, we investigated potential causal relationships among pathologic subjective halitosis, olfactory reference syndrome, social anxiety, and preoccupations with body part odors. A total of 1360 female students (mean age 19.6 ± 1.1 years) answered a self-administered questionnaire regarding pathologic subjective halitosis, olfactory reference syndrome, social anxiety, and preoccupation with odors of body parts such as mouth, body, armpits, and feet. The scale for pathologic subjective halitosis followed that developed by Tsunoda et al.; participants were divided into three groups based on their scores (i.e., levels of pathologic subjective halitosis). A Bayesian network was used to analyze causal relationships between pathologic subjective halitosis, olfactory reference syndrome, social anxiety, and preoccupations with body part odors. We found statistically significant differences in the results for olfactory reference syndrome and social anxiety among the various levels of pathologic subjective halitosis (P < 0.001). Residual analyses indicated that students with severe levels of pathologic subjective halitosis showed greater preoccupations with mouth and body odors (P < 0.05). Bayesian network analysis showed that social anxiety directly influenced pathologic subjective halitosis and olfactory reference syndrome. Preoccupations with mouth and body odors also influenced pathologic subjective halitosis. Social anxiety may be a causal factor of pathologic subjective halitosis and olfactory reference syndrome.

Gender-typical olfactory regulation of sexual behavior in goldfish

PubMed Central

Kawaguchi, Yutaro; Nagaoka, Akira; Kitami, Asana; Mitsuhashi, Tomomi; Hayakawa, Youichi; Kobayashi, Makito

2014-01-01

It is known that olfaction is essential for the occurrence of sexual behavior in male goldfish. Sex pheromones from ovulatory females elicit male sexual behavior, chasing, and sperm releasing act. In female goldfish, ovarian prostaglandin F2α (PGF) elicits female sexual behavior, egg releasing act. It has been considered that olfaction does not affect sexual behavior in female goldfish. In the present study, we re-examined the involvement of olfaction in sexual behavior of female goldfish. Olfaction was blocked in male and female goldfish by two methods: nasal occlusion (NO) which blocks the reception of olfactants, and olfactory tract section (OTX) which blocks transmission of olfactory information from the olfactory bulb to the telencephalon. Sexual behavior of goldfish was induced by administration of PGF to females, an established method for inducing goldfish sexual behavior in both sexes. Sexual behavior in males was suppressed by NO and OTX as previously reported because of lack of pheromone stimulation. In females, NO suppressed sexual behavior but OTX did not affect the occurrence of sexual behavior. Females treated with both NO and OTX performed sexual behavior normally. These results indicate that olfaction is essential in female goldfish to perform sexual behavior as in males but in a different manner. The lack of olfaction in males causes lack of pheromonal stimulation, resulting in no behavior elicited. Whereas the results of female experiments suggest that lack of olfaction in females causes strong inhibition of sexual behavior mediated by the olfactory pathway. Olfactory tract section is considered to block the pathway and remove this inhibition, resulting in the resumption of the behavior. By subtract sectioning of the olfactory tract, it was found that this inhibition was mediated by the medial olfactory tracts, not the lateral olfactory tracts. Thus, it is concluded that goldfish has gender-typical olfactory regulation for sexual behavior. PMID:24817840

Olfactory cytochrome P-450. Studies with suicide substrates of the haemoprotein.

PubMed Central

Reed, C J; Lock, E A; De Matteis, F

1988-01-01

1. The olfactory epithelium of male hamsters has been found to be extremely active in the cumene hydroperoxide-supported oxidation of tetramethylphenylenediamine, and this peroxidase activity has been shown to be cytochrome P-450-dependent. 2. The interaction of a series of suicide substrates of cytochrome P-450 with the hepatic and olfactory mono-oxygenase systems has been assessed by determination of peroxidase, 7-ethoxycoumarin O-de-ethylase (ECOD) and 7-ethoxyresorufin O-de-ethylase (EROD) activities after treatment in vivo with these compounds. Chloramphenicol, OOS-trimethylphosphorothiolate and two dihydropyridines [DDC (3,5-diethoxycarbonyl-1,4-dihydrocollidine) and 4-ethyl DDC (3,5-diethoxycarbonyl-4-ethyl-1,4-dihydro-2,6-dimethylpyridine)] all caused similar percentage inhibitions of hepatic and olfactory activities, but the absolute amounts of enzymic activity lost were considerably greater in the latter tissue. In contrast, halothane had little effect upon hepatic cytochrome P-450-dependent reactions, whereas it severely inhibited those of the olfactory epithelium. 3. The time course of loss and recovery of hepatic and olfactory peroxidase, ECOD and EROD activities after a single dose of 4-ethyl DDC was studied. The rates of loss of activity observed were very similar, irrespective of tissue or reaction examined. In the olfactory epithelium, all three activities recovered concurrently and at a rate similar to that of the hepatic peroxidase activity. In contrast, the hepatic de-ethylation of 7-ethoxycoumarin and 7-ethoxy-resorufin recovered significantly more rapidly. 4. It is suggested that this behaviour is due to 4-ethyl DDC acting not only as a suicidal inhibitor but also as an inducer of certain forms of cytochrome P-450 in the liver; in the olfactory epithelium, however, inactivation, but not induction, occurs. Classical inducing agents were reported to have no effect upon olfactory cytochrome P-450, and in the present study neither phenobarbitone nor beta-naphthoflavone treatment had any effect upon olfactory cytochrome P-450-dependent reactions, although it induced those of the liver. PMID:3263118

Reproduction phase-related expression of GnRH-like immunoreactivity in the olfactory receptor neurons, their projections to the olfactory bulb and in the nervus terminalis in the female Indian major carp Cirrhinus mrigala (Ham.).

PubMed

Biju, K C; Singru, Praful S; Schreibman, Martin P; Subhedar, Nishikant

2003-10-01

The reproductive biology of the Indian major carp Cirrhinus mrigala is tightly synchronized with the seasonal changes in the environment. While the ovaries show growth from February through June, the fish spawn in July-August to coincide with the monsoon; thereafter the fish pass into the postspawning and resting phases. We investigated the pattern of GnRH immunoreactivity in the olfactory system at regular intervals extending over a period of 35 months. Although no signal was detected in the olfactory organ of fish collected from April through February following year, distinct GnRH-like immunoreactivity appeared in the fish collected in March. Intense immunoreactivity was noticed in several olfactory receptor neurons (ORNs) and their axonal fibers as they extend over the olfactory nerve, spread in the periphery of the olfactory bulb (OB), and terminate in the glomerular layer. Strong immunoreactivity was seen in some fascicles of the medial olfactory tracts extending from the OB to the telencephalon. Some neurons of the ganglion cells of nervus terminalis showed GnRH immunostaining during March; no immunoreactivity was detected at other times of the year. Plexus of GnRH immunoreactive fibers extending throughout the bulb represented a different component of the olfactory system; the fiber density showed a seasonal pattern that could be related to the status of gonadal maturity. While it was highest in the prespawning phase, significant reduction in the fiber density was noticed in the fish of spawning and the following regressive phases. Taken together the data suggest that the GnRH in the olfactory system of C. mrigala may play a major role in translation of the environmental cues and influence the downstream signals leading to the stimulation of the brain-pituitary-ovary axis.

Evidence of Neurobiological Changes in the Presymptomatic PINK1 Knockout Rat.

PubMed

Ferris, Craig F; Morrison, Thomas R; Iriah, Sade; Malmberg, Samantha; Kulkarni, Praveen; Hartner, Jochen C; Trivedi, Malav

2018-01-01

Genetic models of Parkinson's disease (PD) coupled with advanced imaging techniques can elucidate neurobiological disease progression, and can help identify early biomarkers before clinical signs emerge. PTEN-induced putative kinase 1 (PINK1) helps protect neurons from mitochondrial dysfunction, and a mutation in the associated gene is a risk factor for recessive familial PD. The PINK1 knockout (KO) rat is a novel model for familial PD that has not been neuroradiologically characterized for alterations in brain structure/function, alongside behavior, prior to 4 months of age. To identify biomarkers of presymptomatic PD in the PINK1 -/- rat at 3 months using magnetic resonance imaging techniques. At postnatal weeks 12-13; one month earlier than previously reported signs of motor and cognitive dysfunction, this study combined imaging modalities, including assessment of quantitative anisotropy across 171 individual brain areas using an annotated MRI rat brain atlas to identify sites of gray matter alteration between wild-type and PINK1 -/- rats. The olfactory system, hypothalamus, thalamus, nucleus accumbens, and cerebellum showed differences in anisotropy between experimental groups. Molecular analyses revealed reduced levels of glutathione, ATP, and elevated oxidative stress in the substantia nigra, striatum and deep cerebellar nuclei. Mitochondrial genes encoding proteins in Complex IV, along with mRNA levels associated with mitochondrial function and genes involved in glutathione synthesis were reduced. Differences in brain structure did not align with any cognitive or motor impairment. These data reveal early markers, and highlight novel brain regions involved in the pathology of PD in the PINK1 -/- rat before behavioral dysfunction occurs.

Olfactory bulb volume in Taiwanese patients with posttraumatic anosmia.

PubMed

Jiang, Rong-San; Chai, Jyh-Wen; Chen, Wen-Hsien; Fuh, Wen-Bin; Chiang, Chin-Ming; Chen, Clayton Chi-Chang

2009-01-01

Olfactory bulb (OB) volume has been shown to be an indicator of olfactory function. However, few studies have been done in Asia to investigate the influence of different disorders on OB volume. Data from patients with posttraumatic anosmia were collected in our department. Their olfactory thresholds were assessed by the phenyl ethyl alcohol threshold test. They were treated with a course of high-dose steroid, and followed up for at least 3 months without any olfactory improvement. Magnetic resonance imaging was subsequently used to measure patients' OB volumes. Subjects who self-reported their olfactory function was normal were also included in the control group for comparison. Fifty-four patients with posttraumatic anosmia and 30 subjects who self-reported their olfactory function was normal were enrolled in this study. The mean right OB volume was 45.2 mm3, and the mean left OB volume was 46.3 mm3 in patients with posttraumatic anosmia. The mean right OB volume was 59.7 mm3, and the mean left OB volume was 66.0 mm3 in control subjects. The OB volumes were significantly lower in patients with posttraumatic anosmia. OB volumes were significantly lower in Taiwanese patients with posttraumatic anosmia.

Olfactory Performance in a Large Sample of Early-Blind and Late-Blind Individuals.

PubMed

Sorokowska, Agnieszka

2016-10-01

Previous examinations of olfactory sensitivity in blind people have produced contradictory findings. Thus, whether visual impairment is associated with increased olfactory abilities is unclear. In the present investigation, I aimed to resolve the existing questions via a relatively large-scale study comprising early-blind (N = 43), and late-blind (N = 41) and sighted (N = 84) individuals matched in terms of gender and age. To compare the results with those of previous studies, I combined data from a free odor identification test, extensive psychophysical testing (Sniffin' Sticks test), and self-assessed olfactory performance. The analyses revealed no significant effects of sight on olfactory threshold, odor discrimination, cued identification, or free identification scores; neither was the performance of the early-blind and late-blind participants significantly different. Additionally, the self-assessed olfactory abilities of the blind people were no different than those of the sighted people. These results suggest that sensory compensation in visually impaired is not pronounced with regards to olfactory abilities as measured by standardized smell tests. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

No oral-cavity-only discrimination of purely olfactory odorants.

PubMed

Stephenson, Dejaimenay; Halpern, Bruce P

2009-02-01

The purely olfactory odorants coumarin, octanoic acid, phenylethyl alcohol, and vanillin had been found to be consistently identified when presented retronasally but could not be identified when presented oral-cavity only (OCO). However, OCO discrimination of these odorants was not tested. Consequently, it remained possible that the oral cavity trigeminal system might provide sufficient information to differentiate these purely olfactory odorants. To evaluate this, 20 participants attempted to discriminate vapor-phase coumarin, octanoic acid, phenylethyl alcohol, and vanillin and, as a control, the trigeminal stimulus peppermint extract, from their glycerin solvent, all presented OCO. None of the purely olfactory odorants could be discriminated OCO, but, as expected, peppermint extract was consistently discriminated. This inability to discriminate clarifies and expands the previous report of lack of OCO identification of purely olfactory odorants. Taken together with prior data, these results suggest that the oral cavity trigeminal system is fully unresponsive to these odorants in vapor phase and that coumarin, octanoic acid, phenylethyl alcohol, and vanillin are indeed purely olfactory stimuli. The OCO discrimination of peppermint extract demonstrated that the absence of discrimination for the purely olfactory odorants was odorant dependent and confirmed that the oral cavity trigeminal system will provide differential response information to some vapor-phase stimuli.

A Pilot Study of the Snap & Sniff Threshold Test.

PubMed

Jiang, Rong-San; Liang, Kai-Li

2018-05-01

The Snap & Sniff ® Threshold Test (S&S) has been recently developed to determine the olfactory threshold. The aim of this study was to further evaluate the validity and test-retest reliability of the S&S. The olfactory thresholds of 120 participants were determined using both the Smell Threshold Test (STT) and the S&S. The participants included 30 normosmic volunteers and 90 patients (60 hyposmic, 30 anosmic). The normosmic participants were retested using the STT and S&S at an intertest interval of at least 1 day. The mean olfactory threshold determined with the S&S was -6.76 for the normosmic participants, -3.79 for the hyposmic patients, and -2 for the anosmic patients. The olfactory thresholds were significantly different across the 3 groups ( P < .001). Snap & Sniff-based and STT-based olfactory thresholds were correlated weakly in the normosmic group (correlation coefficient = 0.162, P = .391) but more strongly correlated in the patient groups (hyposmic: correlation coefficient = 0.376, P = .003; anosmic: correlation coefficient = 1.0). The test-retest correlation for the S&S-based olfactory thresholds was 0.384 ( P = .036). Based on validity and test-retest reliability, we concluded that the S&S is a proper test for olfactory thresholds.

Transgenic mice overexpressing the extracellular domain of NCAM are impaired in working memory and cortical plasticity

PubMed Central

Brennaman, Leann H.; Kochlamazashvili, Gaga; Stoenica, Luminita; Nonneman, Randall J.; Moy, Sheryl S.; Schachner, Melitta; Dityatev, Alexander; Maness, Patricia F.

2011-01-01

The neural cell adhesion molecule, NCAM, is a pivotal regulator of neural development, with key roles in axonal and dendritic growth and synaptic plasticity. Alterations in NCAM expression or proteolytic cleavage have been linked to human neuropsychiatric disorders such as schizophrenia, bipolar disorder and Alzheimer’s disease, and may contribute to cognitive dysfunction. We have generated mice overexpressing the NCAM extracellular (EC) proteolytic cleavage fragment which has been reported to be increased in schizophrenic versus normal brains. These mice show impaired GABAergic innervation and reduced number of apical dendritic spines on pyramidal neurons in the prefrontal cortex (PFC). Here, these NCAM-EC transgenic mice were subjected to behavioral tasks and electrophysiological measurements to determine the impact of structural abnormalities in the PFC on synaptic and cognitive functions. NCAM-EC mice exhibited impaired working memory in a delayed non-match-to-sample task, which requires PFC function, but showed no differences in anxiety, olfactory abilities, or sociability. Transgenic mice displayed impaired long- and short-term potentiation in the PFC but normal synaptic plasticity in the hippocampus, suggesting that the abnormal synaptic innervation in NCAM-EC mice impairs PFC plasticity and alters working memory. These findings may have implications for cognitive dysfunctions observed in neuropsychiatric disorders. PMID:21515372

Egr-1 antisense oligodeoxynucleotide administration into the olfactory bulb impairs olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx.

PubMed

Ganesh, Ambigapathy; Bogdanowicz, Wieslaw; Balamurugan, Krishnaswamy; Ragu Varman, Durairaj; Rajan, Koilmani Emmanuvel

2012-08-30

Postsynaptic densities (PSDs) contain proteins that regulate synaptic transmission. We examined two important examples of these, calcium/calmodulin-dependent protein kinase II (CaMKII) and PSD-95, in regard to the functional role of early growth response gene-1 (egr-1) in regulation of olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx (family Pteropodidae). To test whether activation of egr-1 in the olfactory bulb (OB) is required for olfactory memory of these bats, bilaterally canulated individuals were infused with antisense (AS) or non-sense (NS)-oligodeoxynucleotides (ODN) of egr-1, or with phosphate buffer saline (PBS), 2h before the olfactory training. Our results showed that behavioral training significantly up-regulates immediate early gene (IEG) EGR-1 and key synaptic proteins Synaptotagmin-1(SYT-1), CaMKII and PSD-95, and phosphorylation of CaMKII in the OB at the protein level per se. Subsequently, we observed that egr-1 antisense-ODN infusion in the OB impaired olfactory memory and down regulates the expression of CaMKII and PSD-95, and the phosphorylation of CaMKII but not SYT-1. In contrast, NS-ODN or PBS had no effect on the expression of the PSDs CaMKII or PSD-95, or on the phosphorylation of CaMKII. When the egr-1 NS-ODN was infused in the OB after training for the novel odor there was no effect on olfactory memory. These findings suggest that egr-1 control the activation of CaMKII and PSD-95 during the process of olfactory memory formation. Copyright © 2012 Elsevier B.V. All rights reserved.

Early survival factor deprivation in the olfactory epithelium enhances activity-driven survival

PubMed Central

François, Adrien; Laziz, Iman; Rimbaud, Stéphanie; Grebert, Denise; Durieux, Didier; Pajot-Augy, Edith; Meunier, Nicolas

2013-01-01

The neuronal olfactory epithelium undergoes permanent renewal because of environmental aggression. This renewal is partly regulated by factors modulating the level of neuronal apoptosis. Among them, we had previously characterized endothelin as neuroprotective. In this study, we explored the effect of cell survival factor deprivation in the olfactory epithelium by intranasal delivery of endothelin receptors antagonists to rat pups. This treatment induced an overall increase of apoptosis in the olfactory epithelium. The responses to odorants recorded by electroolfactogram were decreased in treated animal, a result consistent with a loss of olfactory sensory neurons (OSNs). However, the treated animal performed better in an olfactory orientation test based on maternal odor compared to non-treated littermates. This improved performance could be due to activity-dependent neuronal survival of OSNs in the context of increased apoptosis level. In order to demonstrate it, we odorized pups with octanal, a known ligand for the rI7 olfactory receptor (Olr226). We quantified the number of OSN expressing rI7 by RT-qPCR and whole mount in situ hybridization. While this number was reduced by the survival factor removal treatment, this reduction was abolished by the presence of its ligand. This improved survival was optimal for low concentration of odorant and was specific for rI7-expressing OSNs. Meanwhile, the number of rI7-expressing OSNs was not affected by the odorization in non-treated littermates; showing that the activity-dependant survival of OSNs did not affect the OSN population during the 10 days of odorization in control conditions. Overall, our study shows that when apoptosis is promoted in the olfactory mucosa, the activity-dependent neuronal plasticity allows faster tuning of the olfactory sensory neuron population toward detection of environmental odorants. PMID:24399931

Ontogenetic changes in responses to settlement cues by Anemonefish

NASA Astrophysics Data System (ADS)

Dixson, D. L.; Munday, P. L.; Pratchett, M.; Jones, G. P.

2011-12-01

Population connectivity for most marine species is dictated by dispersal during the pelagic larval stage. Although reef fish larvae are known to display behavioral adaptations that influence settlement site selection, little is known about the development of behavioral preferences throughout the larval phase. Whether larvae are attracted to the same sensory cues throughout their larval phase, or exhibit distinct ontogenetic shifts in sensory preference is unknown. Here, we demonstrate an ontogenetic shift in olfactory cue preferences for two species of anemonefish, a process that could aid in understanding both patterns of dispersal and settlement. Aquarium-bred naïve Amphiprion percula and A. melanopus larvae were tested for olfactory preference of relevant reef-associated chemical cues throughout the 11-day pelagic larval stage. Age posthatching had a significant effect on the preference for olfactory cues from host anemones and live corals for both species. Preferences of olfactory cues from tropical plants of A. percula, increased by approximately ninefold between hatching and settlement, with A. percula larvae showing a fivefold increase in preference for the olfactory cue produced by the grass species. Larval age had no effect on the olfactory preference for untreated seawater over the swamp-based tree Melaleuca nervosa, which was always avoided compared with blank seawater. These results indicate that reef fish larvae are capable of utilizing olfactory cues early in the larval stage and may be predisposed to disperse away from reefs, with innate olfactory preferences drawing newly hatched larvae into the pelagic environment. Toward the end of the larval phase, larvae become attracted to the olfactory cues of appropriate habitats, which may assist them in identification of and navigation toward suitable settlement sites.

Development of the olfactory pathways in platypus and echidna.

PubMed

Ashwell, Ken W S

2012-01-01

The two groups of living monotremes (platypus and echidnas) have remarkably different olfactory structures in the adult. The layers of the main olfactory bulb of the short-beaked echidna are extensively folded, whereas those of the platypus are not. Similarly, the surface area of the piriform cortex of the echidna is large and its lamination complex, whereas in the platypus it is small and simple. It has been argued that the modern echidnas are derived from a platypus-like ancestor, in which case the extensive olfactory specializations of the modern echidnas would have developed relatively recently in monotreme evolution. In this study, the development of the constituent structures of the olfactory pathway was studied in sectioned platypus and echidna embryos and post-hatchlings at the Museum für Naturkunde, Berlin, Germany. The aim was to determine whether the olfactory structures follow a similar maturational path in the two monotremes during embryonic and early post-hatching ages or whether they show very different developmental paths from the outset. The findings indicate that anatomical differences in the central olfactory system between the short-beaked echidna and the platypus begin to develop immediately before hatching, although details of differences in nasal cavity architecture emerge progressively during late post-hatching life. These findings are most consistent with the proposition that the two modern monotreme lineages have followed independent evolutionary paths from a less olfaction-specialized ancestor. The monotreme olfactory pathway does not appear to be sufficiently structurally mature at birth to allow olfaction-mediated behaviour, because central components of both the main and accessory olfactory system have not differentiated at the time of hatching. Copyright © 2011 S. Karger AG, Basel.

Cladistic Analysis of Olfactory and Vomeronasal Systems

PubMed Central

Ubeda-Bañon, Isabel; Pro-Sistiaga, Palma; Mohedano-Moriano, Alicia; Saiz-Sanchez, Daniel; de la Rosa-Prieto, Carlos; Gutierrez-Castellanos, Nicolás; Lanuza, Enrique; Martinez-Garcia, Fernando; Martinez-Marcos, Alino

2010-01-01

Most tetrapods possess two nasal organs for detecting chemicals in their environment, which are the sensory detectors of the olfactory and vomeronasal systems. The seventies’ view that the olfactory system was only devoted to sense volatiles, whereas the vomeronasal system was exclusively specialized for pheromone detection was challenged by accumulating data showing deep anatomical and functional interrelationships between both systems. In addition, the assumption that the vomeronasal system appeared as an adaptation to terrestrial life is being questioned as well. The aim of the present work is to use a comparative strategy to gain insight in our understanding of the evolution of chemical “cortex.” We have analyzed the organization of the olfactory and vomeronasal cortices of reptiles, marsupials, and placental mammals and we have compared our findings with data from other taxa in order to better understand the evolutionary history of the nasal sensory systems in vertebrates. The olfactory and vomeronsasal cortices have been re-investigated in garter snakes (Thamnophis sirtalis), short-tailed opossums (Monodelphis domestica), and rats (Rattus norvegicus) by tracing the efferents of the main and accessory olfactory bulbs using injections of neuroanatomical anterograde tracers (dextran-amines). In snakes, the medial olfactory tract is quite evident, whereas the main vomeronasal-recipient structure, the nucleus sphaericus is a folded cortical-like structure, located at the caudal edge of the amygdala. In marsupials, which are acallosal mammals, the rhinal fissure is relatively dorsal and the olfactory and vomeronasal cortices relatively expanded. Placental mammals, like marsupials, show partially overlapping olfactory and vomeronasal projections in the rostral basal telencephalon. These data raise the interesting question of how the telencephalon has been re-organized in different groups according to the biological relevance of chemical senses. PMID:21290004

Cladistic analysis of olfactory and vomeronasal systems.

PubMed

Ubeda-Bañon, Isabel; Pro-Sistiaga, Palma; Mohedano-Moriano, Alicia; Saiz-Sanchez, Daniel; de la Rosa-Prieto, Carlos; Gutierrez-Castellanos, Nicolás; Lanuza, Enrique; Martinez-Garcia, Fernando; Martinez-Marcos, Alino

2011-01-01

Most tetrapods possess two nasal organs for detecting chemicals in their environment, which are the sensory detectors of the olfactory and vomeronasal systems. The seventies' view that the olfactory system was only devoted to sense volatiles, whereas the vomeronasal system was exclusively specialized for pheromone detection was challenged by accumulating data showing deep anatomical and functional interrelationships between both systems. In addition, the assumption that the vomeronasal system appeared as an adaptation to terrestrial life is being questioned as well. The aim of the present work is to use a comparative strategy to gain insight in our understanding of the evolution of chemical "cortex." We have analyzed the organization of the olfactory and vomeronasal cortices of reptiles, marsupials, and placental mammals and we have compared our findings with data from other taxa in order to better understand the evolutionary history of the nasal sensory systems in vertebrates. The olfactory and vomeronsasal cortices have been re-investigated in garter snakes (Thamnophis sirtalis), short-tailed opossums (Monodelphis domestica), and rats (Rattus norvegicus) by tracing the efferents of the main and accessory olfactory bulbs using injections of neuroanatomical anterograde tracers (dextran-amines). In snakes, the medial olfactory tract is quite evident, whereas the main vomeronasal-recipient structure, the nucleus sphaericus is a folded cortical-like structure, located at the caudal edge of the amygdala. In marsupials, which are acallosal mammals, the rhinal fissure is relatively dorsal and the olfactory and vomeronasal cortices relatively expanded. Placental mammals, like marsupials, show partially overlapping olfactory and vomeronasal projections in the rostral basal telencephalon. These data raise the interesting question of how the telencephalon has been re-organized in different groups according to the biological relevance of chemical senses.

Olfactory Cleft Endoscopy Scale correlates with olfactory metrics in patients with chronic rhinosinusitis

PubMed Central

Soler, Zachary M.; Hyer, J. Madison; Karnezis, Tom T.; Schlosser, Rodney J.

2015-01-01

Introduction Olfactory loss affects a majority of patients with chronic rhinosinusitis (CRS). Traditional objective measures of disease severity, including endoscopy scales, focus upon the paranasal sinuses and often have weak correlation to olfaction. Methods Adults with CRS were prospectively evaluated by blinded reviewers with a novel Olfactory Cleft Endoscopy Scale (OCES) that evaluated discharge, polyps, edema, crusting and scarring of the olfactory cleft. Objective olfactory function was assessed using “Sniffin’ Sticks testing, including composite threshold-discrimination-identification (TDI) scores. Olfactory-specific quality-of-life was evaluated using the short modified version of the Questionnaire of Olfactory Disorders (QOD-NS). Inter- and intra-rater reliability was assessed among 3 reviewers for OCES grading. Multivariate linear regression was then used to test associations between OCES scores and measures of olfaction, controlling for potential confounding factors. Results The OCES score was evaluated in 38 patients and had a high overall reliability (ICC=0.92; 95% CI: 0.91–0.96). The OCES significantly correlated with objective olfaction as measured by TDI score (p<0.001), with TDI score falling by 1.13 points for every 1 point increase in OCES score. Similar significant associations were found for threshold, discrimination, and identification scores (p<0.003 for all) after controlling for age, gender, race, and reviewer/review. The OCES was also highly associated with patient-reported QOD-NS scores (p=0.009). Conclusion A novel olfactory cleft endoscopy scale shows high reliability and correlates with both objective and patient-reported olfaction in patients with CRS. Further studies to determine prognostic value and responsiveness to change are warranted. PMID:26718315

Aquatic adaptations in the nose of carnivorans: evidence from the turbinates

PubMed Central

Van Valkenburgh, Blaire; Curtis, Abigail; Samuels, Joshua X; Bird, Deborah; Fulkerson, Brian; Meachen-Samuels, Julie; Slater, Graham J

2011-01-01

Inside the mammalian nose lies a labyrinth of bony plates covered in epithelium collectively known as turbinates. Respiratory turbinates lie anteriorly and aid in heat and water conservation, while more posterior olfactory turbinates function in olfaction. Previous observations on a few carnivorans revealed that aquatic species have relatively large, complex respiratory turbinates and greatly reduced olfactory turbinates compared with terrestrial species. Body heat is lost more quickly in water than air and increased respiratory surface area likely evolved to minimize heat loss. At the same time, olfactory surface area probably diminished due to a decreased reliance on olfaction when foraging under water. To explore how widespread these adaptations are, we documented scaling of respiratory and olfactory turbinate surface area with body size in a variety of terrestrial, freshwater, and marine carnivorans, including pinnipeds, mustelids, ursids, and procyonids. Surface areas were estimated from high-resolution CT scans of dry skulls, a novel approach that enabled a greater sampling of taxa than is practical with fresh heads. Total turbinate, respiratory, and olfactory surface areas correlate well with body size (r2 ≥ 0.7), and are relatively smaller in larger species. Relative to body mass or skull length, aquatic species have significantly less olfactory surface area than terrestrial species. Furthermore, the ratio of olfactory to respiratory surface area is associated with habitat. Using phylogenetic comparative methods, we found strong support for convergence on 1 : 3 proportions in aquatic taxa and near the inverse in terrestrial taxa, indicating that aquatic mustelids and pinnipeds independently acquired similar proportions of olfactory to respiratory turbinates. Constraints on turbinate surface area in the nasal chamber may result in a trade-off between respiratory and olfactory function in aquatic mammals. PMID:21198587

Lack of TRPM5-Expressing Microvillous Cells in Mouse Main Olfactory Epithelium Leads to Impaired Odor-Evoked Responses and Olfactory-Guided Behavior in a Challenging Chemical Environment

PubMed Central

Lemons, Kayla; Aoudé, Imad; Ogura, Tatsuya; Mbonu, Kenechukwu; Matsumoto, Ichiro; Arakawa, Hiroyuki

2017-01-01

The mammalian main olfactory epithelium (MOE) modifies its activities in response to changes in the chemical environment. This process is essential for maintaining the functions of the olfactory system and the upper airway. However, mechanisms involved in this functional maintenance, especially those occurring via paracrine regulatory pathways within the multicellular MOE, are poorly understood. Previously, a population of non-neuronal, transient receptor potential M5-expressing microvillous cells (TRPM5-MCs) was identified in the MOE, and the initial characterization of these cells showed that they are cholinergic and responsive to various xenobiotics including odorants at high concentrations. Here, we investigated the role of TRPM5-MCs in maintaining olfactory function using transcription factor Skn-1a knockout (Skn-1a-/-) mice, which lack TRPM5-MCs in the MOE. Under our standard housing conditions, Skn-1a-/- mice do not differ significantly from control mice in odor-evoked electro-olfactogram (EOG) responses and olfactory-guided behaviors, including finding buried food and preference reactions to socially and sexually relevant odors. However, after a 2-wk exposure to high-concentration odor chemicals and chitin powder, Skn-1a-/- mice exhibited a significant reduction in their odor and pheromone-evoked EOG responses. Consequently, their olfactory-guided behaviors were impaired compared with vehicle-exposed Skn-1a-/- mice. Conversely, the chemical exposure did not induce significant changes in the EOG responses and olfactory behaviors of control mice. Therefore, our physiological and behavioral results indicate that TRPM5-MCs play a protective role in maintaining the olfactory function of the MOE. PMID:28612045

Microvasculature of the Olfactory Organ in the Japanese Monkey (Macaca fuscata fuscata)

NASA Astrophysics Data System (ADS)

Okada, Shigenori; Schraufnagel, Dean E.

2002-06-01

Olfaction is an important and primitive sense. As its importance has changed with evolution, anatomic adjustments have occurred in its structure and vasculature. Primates are a family of vertebrates that have had to develop their visual system to adapt to the arboreal environment and have evolved from a macrosmatic to a microsmatic species as the optic system has enlarged. This has resulted in anatomic changes of a small but critical area at the base of the brain. This paper describes the three-dimensional vascular anatomy of the olfactory organ of the Japanese monkey (Macaca fuscata fuscata). This is best understood by dividing the organ into three parts: the olfactory tract, olfactory bulb, and olfactory nerves in the nasal mucosa. The bulb can be partitioned into an outer or cortical part and inner or medullary part. The vasculature and tissue were examined grossly and with light microscopy and scanning electron microscopy of vascular corrosion casts. The olfactory tract and bulb were supplied by an arteriole from the anterior cerebral artery on each side. The tract was supplied by capillaries running spirally with a coarse network. At the olfactory bulb, the arteriole ramified into the intracortical and medullary branches that formed capillary networks. The bulbar intracortical capillaries were divided into two layers with different densities and vascular patterns. The capillaries of the superficial layer had a ladder-like pattern. The branches that ran into the medulla of the olfactory bulb were more widely spaced. Twigs from the posterior ethmoidal artery ran along the nerve fiber and formed intra- and extrafascicular networks. Each region of the olfactory organ had characteristic three-dimensional vascular patterns that were related to their cellular architecture.

Sadness might isolate you in a non-smelling world: olfactory perception and depression

PubMed Central

Schablitzky, Sylvia; Pause, Bettina M.

2014-01-01

Major depressive disorder (MDD) occurs with a high prevalence among mental illnesses. MDD patients experience sadness and hopelessness, with blunted affective reactivity. However, such depressive episodes are also key symptoms in other depressive disorders, like Bipolar Disorder (BPD) or Seasonal Affective Disorder (SAD). Moreover, depressive symptoms can also be found in healthy individuals, but are experienced as less severe or for a shorter duration than in patients. Here, it is aimed to summarize studies investigating odor perception in depression, including depressive states in healthy individuals and patient populations. Odor perception in depression has been assessed with psychophysical methods (olfactory sensitivity, odor identification, and discrimination), and odor ratings (intensity, emotional valence, familiarity). In addition, some studies investigated affective reactions to odors, and physiological and anatomical correlates of odor perception in depression. The summary reveals that MDD is associated with reduced olfactory sensitivity. However, odor identification and discrimination scores seem to be unaffected by depression. The reduced olfactory sensitivity might be associated with a reduced ability to encode olfactory information and a reduced volume of the olfactory bulb. While similar processes seem to occur in healthy individuals experiencing depressive states, they have not been observed in BPD or SAD patients. However, in order to conclude that the reduced olfactory sensitivity is directly linked to depression, it is suggested that studies should implement control measures of cognitive performances or perceptual abilities in other stimulus modalities. It is concluded that the reduced olfactory performance in MDD patients seems to be disorder-, modality-, and test-specific, and that the application of an appropriate olfactory and cognitive test-battery might be highly useful in the differential diagnosis of MDD. PMID:24570666

Methods to measure olfactory behavior in mice

PubMed Central

Zou, Junhui; Wang, Wenbin; Pan, Yung-Wei; Lu, Song; Xia, Zhengui

2015-01-01

Mice rely on the sense of olfaction to detect food sources, recognize social and mating partners, and avoid predators. Many behaviors of mice including learning and memory, social interaction, fear, and anxiety are closely associated with their function of olfaction, and behavior tasks designed to evaluate those brain functions may use odors as cues. Accurate assessment of olfaction is not only essential for the study of olfactory system but also critical for proper interpretation of various mouse behaviors especially learning and memory, emotionality and affect, and sociality. Here we describe a series of behavior experiments that offer multidimensional and quantitative assessments for mouse’s olfactory function, including olfactory habituation, discrimination, odor preference, odor detection sensitivity, and olfactory memory, to both social and nonsocial odors. PMID:25645244

The Pig Olfactory Brain: A Primer

PubMed Central

Feldman, Sanford; Osterberg, Stephen K.

2016-01-01

Despite the fact that pigs are reputed to have excellent olfactory abilities, few studies have examined regions of the pig brain involved in the sense of smell. The present study provides an overview of the olfactory bulb, anterior olfactory nucleus, and piriform cortex of adult pigs using several approaches. Nissl, myelin, and Golgi stains were used to produce a general overview of the organization of the regions and confocal microscopy was employed to examine 1) projection neurons, 2) GABAergic local circuit neurons that express somatostatin, parvalbumin, vasoactive intestinal polypeptide, or calretinin, 3) neuromodulatory fibers (cholinergic and serotonergic), and 4) glia (astrocytes and microglia). The findings revealed that pig olfactory structures are quite large, highly organized and follow the general patterns observed in mammals. PMID:26936231

Electrophysiological mapping of the accessory olfactory bulb of the rabbit (Oryctolagus cuniculus).

PubMed

van Groen, T; Ruardy, L; da Silva, F H

1986-07-01

Field potentials elicited by electrical stimulation of the vomeronasal nerve were measured in the accessory olfactory bulb of the rabbit. Maps were made of the distribution of surface field potentials and of the corresponding depth profiles. The surface maps followed closely the contours of the accessory olfactory bulb: at the frontal border the field potential tended to zero and at the center of the structure the field potential attained a maximum. Depth profiles of the field potentials through the accessory olfactory bulb presented a surface-negative wave and, in depth, a positive wave. The polarity reversal occurred at the deep part of the granule cell layer. The zero equipotential line followed closely the curvature of the granule cell layer. Current source density analysis of the depth profiles revealed a main sink at the external plexiform and granule cell layers. This indicates that the main activity in the accessory olfactory bulb is generated by the synapses between the mitral cells and the granule cells as is found in the main olfactory bulb.

The number of functional olfactory receptor genes and the relative size of olfactory brain structures are poor predictors of olfactory discrimination performance with enantiomers.

PubMed

Laska, Matthias; Genzel, Daria; Wieser, Alexandra

2005-02-01

The ability of four squirrel monkeys and three pigtail macaques to distinguish between nine enantiomeric odor pairs sharing an isopropenyl group at the chiral center was investigated in terms of a conditioning paradigm. All animals from both species were able to discriminate between the optical isomers of limonene, carvone, dihydrocarvone, dihydrocarveole and dihydrocarvyl acetate, whereas they failed to distinguish between the (+)- and (-)-forms of perillaaldehyde and limonene oxide. The pigtail macaques, but not the squirrel monkeys, also discriminated between the antipodes of perillaalcohol and isopulegol. A comparison of the across-task patterns of discrimination performance shows a high degree of similarity among the two primate species and also between these nonhuman primates and human subjects tested in an earlier study on the same tasks. These findings suggest that between-species comparisons of the relative size of olfactory brain structures or of the number of functional olfactory receptor genes are poor predictors of olfactory discrimination performance with enantiomers.

PEGylation of zinc nanoparticles amplifies their ability to enhance olfactory responses to odorant

PubMed Central

Singletary, Melissa; Hagerty, Samantha; Muramoto, Shin; Daniels, Yasmine; MacCrehan, William A.; Stan, Gheorghe; Lau, June W.; Pustovyy, Oleg; Globa, Ludmila; Morrison, Edward E.; Sorokulova, Iryna

2017-01-01

Olfactory responses are intensely enhanced with the addition of endogenous and engineered primarily-elemental small zinc nanoparticles (NPs). With aging, oxidation of these Zn nanoparticles eliminated the observed enhancement. The design of a polyethylene glycol coating to meet storage requirements of engineered zinc nanoparticles is evaluated to achieve maximal olfactory benefit. The zinc nanoparticles were covered with 1000 g/mol or 400 g/mol molecular weight polyethylene glycol (PEG). Non-PEGylated and PEGylated zinc nanoparticles were tested by electroolfactogram with isolated rat olfactory epithelium and odorant responses evoked by the mixture of eugenol, ethyl butyrate and (±) carvone after storage at 278 K (5 oC), 303 K (30 oC) and 323 K (50 oC). The particles were analyzed by atomic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and laser Doppler velocimetry. Our data indicate that stored ZnPEG400 nanoparticles maintain physiologically-consistent olfactory enhancement for over 300 days. These engineered Nanoparticles support future applications in olfactory research, sensitive detection, and medicine. PMID:29261701

Olfactory Mechanisms for Discovery of Odorants to Reduce Insect-Host Contact

PubMed Central

Clark, Jonathan T.; Ray, Anandasankar

2016-01-01

Insects have developed highly sophisticated and sensitive olfactory systems to find animal or plant hosts for feeding. Some insects vector pathogens that cause diseases in hundreds of millions of people and destroy billions of dollars of food products every year. There is great interest, therefore, in understanding how the insect olfactory system can be manipulated to reduce their contact with hosts. Here, we review recent advances in our understanding of insect olfactory detection mechanisms, which may serve as a foundation for designing insect control programs based on manipulation of their behaviors by using odorants. Because every insect species has a unique set of olfactory receptors and olfactory-mediated behaviors, we focus primarily on general principles of odor detection that potentially apply to most insects. While these mechanisms have emerged from studies on model systems for study of insect olfaction, such as Drosophila melanogaster, they provide a foundation for discovery of odorants to repel insects or reduce host-seeking behavior. PMID:27628342

Olfactory preservation during anterior interhemispheric approach for anterior skull base lesions: technical note.

PubMed

Matano, Fumihiro; Murai, Yasuo; Mizunari, Takayuki; Tateyama, Kojiro; Kobayashi, Shiro; Adachi, Koji; Kamiyama, Hiroyasu; Morita, Akio; Teramoto, Akira

2016-01-01

Anosmia is not a rare complication of surgeries that employ the anterior interhemispheric approach. Here, we present a fibrin-gelatin fixation method that provides reinforcement and moisture to help preserve the olfactory nerve when using the anterior interhemispheric approach and describe the results and outcomes of this technique. We analyze the outcomes with this technique in 45 patients who undergo surgery for aneurysms, brain tumors, or other pathologies via the anterior interhemispheric approach. Anosmia occurred in 4 patients (8.8%); it was transient in 2 (4.4%) and permanent in the remaining 2 (4.4%). Brain tumors clearly attached to the olfactory nerve were resected in the patients with permanent anosmia. We found a significant difference in the presence of anosmia between patients with or without lesions that were attaching the olfactory nerve (p = 0.011). Our results suggested that fibrin-gelatin fixation method can reduce the reported risk of anosmia. However, the possibility of olfactory nerve damage is relatively high when operating on brain tumors attaching olfactory nerve.

Implementation of olfactory bulb glomerular-layer computations in a digital neurosynaptic core.

PubMed

Imam, Nabil; Cleland, Thomas A; Manohar, Rajit; Merolla, Paul A; Arthur, John V; Akopyan, Filipp; Modha, Dharmendra S

2012-01-01

We present a biomimetic system that captures essential functional properties of the glomerular layer of the mammalian olfactory bulb, specifically including its capacity to decorrelate similar odor representations without foreknowledge of the statistical distributions of analyte features. Our system is based on a digital neuromorphic chip consisting of 256 leaky-integrate-and-fire neurons, 1024 × 256 crossbar synapses, and address-event representation communication circuits. The neural circuits configured in the chip reflect established connections among mitral cells, periglomerular cells, external tufted cells, and superficial short-axon cells within the olfactory bulb, and accept input from convergent sets of sensors configured as olfactory sensory neurons. This configuration generates functional transformations comparable to those observed in the glomerular layer of the mammalian olfactory bulb. Our circuits, consuming only 45 pJ of active power per spike with a power supply of 0.85 V, can be used as the first stage of processing in low-power artificial chemical sensing devices inspired by natural olfactory systems.

Designer lipid-like peptides: a class of detergents for studying functional olfactory receptors using commercial cell-free systems.

PubMed

Corin, Karolina; Baaske, Philipp; Ravel, Deepali B; Song, Junyao; Brown, Emily; Wang, Xiaoqiang; Wienken, Christoph J; Jerabek-Willemsen, Moran; Duhr, Stefan; Luo, Yuan; Braun, Dieter; Zhang, Shuguang

2011-01-01

A crucial bottleneck in membrane protein studies, particularly G-protein coupled receptors, is the notorious difficulty of finding an optimal detergent that can solubilize them and maintain their stability and function. Here we report rapid production of 12 unique mammalian olfactory receptors using short designer lipid-like peptides as detergents. The peptides were able to solubilize and stabilize each receptor. Circular dichroism showed that the purified olfactory receptors had alpha-helical secondary structures. Microscale thermophoresis suggested that the receptors were functional and bound their odorants. Blot intensity measurements indicated that milligram quantities of each olfactory receptor could be produced with at least one peptide detergent. The peptide detergents' capability was comparable to that of the detergent Brij-35. The ability of 10 peptide detergents to functionally solubilize 12 olfactory receptors demonstrates their usefulness as a new class of detergents for olfactory receptors, and possibly other G-protein coupled receptors and membrane proteins.

Designer Lipid-Like Peptides: A Class of Detergents for Studying Functional Olfactory Receptors Using Commercial Cell-Free Systems

PubMed Central

Corin, Karolina; Baaske, Philipp; Ravel, Deepali B.; Song, Junyao; Brown, Emily; Wang, Xiaoqiang; Wienken, Christoph J.; Jerabek-Willemsen, Moran; Duhr, Stefan; Luo, Yuan; Braun, Dieter; Zhang, Shuguang

2011-01-01

A crucial bottleneck in membrane protein studies, particularly G-protein coupled receptors, is the notorious difficulty of finding an optimal detergent that can solubilize them and maintain their stability and function. Here we report rapid production of 12 unique mammalian olfactory receptors using short designer lipid-like peptides as detergents. The peptides were able to solubilize and stabilize each receptor. Circular dichroism showed that the purified olfactory receptors had alpha-helical secondary structures. Microscale thermophoresis suggested that the receptors were functional and bound their odorants. Blot intensity measurements indicated that milligram quantities of each olfactory receptor could be produced with at least one peptide detergent. The peptide detergents' capability was comparable to that of the detergent Brij-35. The ability of 10 peptide detergents to functionally solubilize 12 olfactory receptors demonstrates their usefulness as a new class of detergents for olfactory receptors, and possibly other G-protein coupled receptors and membrane proteins. PMID:22132066

Using Single Sensillum Recording to Detect Olfactory Neuron Responses of Bed Bugs to Semiochemicals.

PubMed

Liu, Feng; Liu, Nannan

2016-01-18

The insect olfactory system plays an important role in detecting semiochemicals in the environment. In particular, the antennal sensilla which house single or multiple neurons inside, are considered to make the major contribution in responding to the chemical stimuli. By directly recording action potential in the olfactory sensillum after exposure to stimuli, single sensillum recording (SSR) technique provides a powerful approach for investigating the neural responses of insects to chemical stimuli. For the bed bug, which is a notorious human parasite, multiple types of olfactory sensillum have been characterized. In this study, we demonstrated neural responses of bed bug olfactory sensilla to two chemical stimuli and the dose-dependent responses to one of them using the SSR method. This approach enables researchers to conduct early screening for individual chemical stimuli on the bed bug olfactory sensilla, which would provide valuable information for the development of new bed bug attractants or repellents and benefits the bed bug control efforts.

Using Single Sensillum Recording to Detect Olfactory Neuron Responses of Bed Bugs to Semiochemicals

PubMed Central

Liu, Feng; Liu, Nannan

2016-01-01

The insect olfactory system plays an important role in detecting semiochemicals in the environment. In particular, the antennal sensilla which house single or multiple neurons inside, are considered to make the major contribution in responding to the chemical stimuli. By directly recording action potential in the olfactory sensillum after exposure to stimuli, single sensillum recording (SSR) technique provides a powerful approach for investigating the neural responses of insects to chemical stimuli. For the bed bug, which is a notorious human parasite, multiple types of olfactory sensillum have been characterized. In this study, we demonstrated neural responses of bed bug olfactory sensilla to two chemical stimuli and the dose-dependent responses to one of them using the SSR method. This approach enables researchers to conduct early screening for individual chemical stimuli on the bed bug olfactory sensilla, which would provide valuable information for the development of new bed bug attractants or repellents and benefits the bed bug control efforts. PMID:26862929

Human Neural Cells Transiently Express Reelin during Olfactory Placode Development

PubMed Central

Antal, M. Cristina; Samama, Brigitte; Ghandour, M. Said; Boehm, Nelly

2015-01-01

Reelin, an extracellular glycoprotein is essential for migration and correct positioning of neurons during development. Since the olfactory system is known as a source of various migrating neuronal cells, we studied Reelin expression in the two chemosensory olfactory systems, main and accessory, during early developmental stages of human foetuses/embryos from Carnegie Stage (CS) 15 to gestational week (GW) 14. From CS 15 to CS 18, but not at later stages, a transient expression of Reelin was detected first in the presumptive olfactory and then in the presumptive vomeronasal epithelium. During the same period, Reelin-positive cells detach from the olfactory/vomeronasal epithelium and migrate through the mesenchyme beneath the telencephalon. Dab 1, an adaptor protein of the Reelin pathway, was simultaneously expressed in the migratory mass from CS16 to CS17 and, at later stages, in the presumptive olfactory ensheathing cells. Possible involvements of Reelin and Dab 1 in the peripheral migrating stream are discussed. PMID:26270645

Olfactory stimulation modulates the blood glucose level in rats.

PubMed

Tsuji, Tadataka; Tanaka, Susumu; Bakhshishayan, Sanam; Kogo, Mikihiko; Yamamoto, Takashi

2018-01-01

In both humans and animals, chemosensory stimuli, including odors and tastes, induce a variety of physiologic and mental responses related to energy homeostasis, such as glucose kinetics. The present study examined the importance of olfactory function in glucose kinetics following ingestion behavior in a simplified experimental scenario. We applied a conventional glucose tolerance test to rats with and without olfactory function and analyzed subsequent blood glucose (BG) curves in detail. The loss of olfactory input due to experimental damage to the olfactory mucosa induced a marked decrease in the area under the BG curve. Exposure to grapefruit odor and its main component, limonene, both of which activate the sympathetic nerves, before glucose loading also greatly depressed the BG curve. Pre-loading exposure to lavender odor, a parasympathetic activator, stabilized the BG level. These results suggest that olfactory function is important for proper glucose kinetics after glucose intake and that certain fragrances could be utilized as tools for controlling BG levels.

Olfactory behavior and physiology are disrupted in prion protein knockout mice.

PubMed

Le Pichon, Claire E; Valley, Matthew T; Polymenidou, Magdalini; Chesler, Alexander T; Sagdullaev, Botir T; Aguzzi, Adriano; Firestein, Stuart

2009-01-01

The prion protein PrP(C) is infamous for its role in disease, but its normal physiological function remains unknown. Here we found a previously unknown behavioral phenotype of Prnp(-/-) mice in an odor-guided task. This phenotype was manifest in three Prnp knockout lines on different genetic backgrounds, which provides strong evidence that the phenotype is caused by a lack of PrP(C) rather than by other genetic factors. Prnp(-/-) mice also showed altered behavior in a second olfactory task, suggesting that the phenotype is olfactory specific. Furthermore, PrP(C) deficiency affected oscillatory activity in the deep layers of the main olfactory bulb, as well as dendrodendritic synaptic transmission between olfactory bulb granule and mitral cells. Notably, both the behavioral and electrophysiological alterations found in Prnp(-/-) mice were rescued by transgenic neuronal-specific expression of PrP(C). These data suggest that PrP(C) is important in the normal processing of sensory information by the olfactory system.

Synchronized Activity in The Main and Accessory Olfactory Bulbs and Vomeronasal Amygdala Elicited by Chemical Signals in Freely Behaving Mice.

PubMed

Pardo-Bellver, Cecília; Martínez-Bellver, Sergio; Martínez-García, Fernando; Lanuza, Enrique; Teruel-Martí, Vicent

2017-08-30

Chemosensory processing in mammals involves the olfactory and vomeronasal systems, but how the activity of both circuits is integrated is unknown. In our study, we recorded the electrophysiological activity in the olfactory bulbs and the vomeronasal amygdala in freely behaving mice exploring a battery of neutral and conspecific stimuli. The exploration of stimuli, including a neutral stimulus, induced synchronic activity in the olfactory bulbs characterized by a dominant theta rhythmicity, with specific theta-gamma coupling, distinguishing between vomeronasal and olfactory structures. The correlated activation of the bulbs suggests a coupling between the stimuli internalization in the nasal cavity and the vomeronasal pumping. In the amygdala, male stimuli are preferentially processed in the medial nucleus, whereas female cues induced a differential response in the posteromedial cortical amygdala. Thus, particular theta-gamma patterns in the olfactory network modulates the integration of chemosensory information in the amygdala, allowing the selection of an appropriate behaviour.

Age-associated loss of selectivity in human olfactory sensory neurons

PubMed Central

Rawson, Nancy E.; Gomez, George; Cowart, Beverly J.; Kriete, Andres; Pribitkin, Edmund; Restrepo, Diego

2011-01-01

We report a cross-sectional study of olfactory impairment with age based on both odorant-stimulated responses of human olfactory sensory neurons (OSNs) and tests of olfactory threshold sensitivity. A total of 621 OSNs from 440 subjects in two age groups of younger ( 45 years) and older (≥60 years) subjects were investigated using fluorescence intensity ratio fura-2 imaging. OSNs were tested for responses to two odorant mixtures, as well as to subsets of and individual odors in those mixtures. Whereas cells from younger donors were highly selective in the odorants to which they responded, cells from older donors were more likely to respond to multiple odor stimuli, despite a loss in these subjects’ absolute olfactory sensitivity, suggesting a loss of specificity. This degradation in peripheral cellular specificity may impact odor discrimination and olfactory adaptation in the elderly. It is also possible that chronic adaptation as a result of reduced specificity contributes to observed declines in absolute sensitivity. PMID:22074806

Fetal alcohol exposure leads to abnormal olfactory bulb development and impaired odor discrimination in adult mice.

PubMed

Akers, Katherine G; Kushner, Steven A; Leslie, Ana T; Clarke, Laura; van der Kooy, Derek; Lerch, Jason P; Frankland, Paul W

2011-07-07

Children whose mothers consumed alcohol during pregnancy exhibit widespread brain abnormalities and a complex array of behavioral disturbances. Here, we used a mouse model of fetal alcohol exposure to investigate relationships between brain abnormalities and specific behavioral alterations during adulthood. Mice drank a 10% ethanol solution throughout pregnancy. When fetal alcohol-exposed offspring reached adulthood, we used high resolution MRI to conduct a brain-wide screen for structural changes and found that the largest reduction in volume occurred in the olfactory bulbs. Next, we tested adult mice in an associative olfactory task and found that fetal alcohol exposure impaired discrimination between similar odors but left odor memory intact. Finally, we investigated olfactory bulb neurogenesis as a potential mechanism by performing an in vitro neurosphere assay, in vivo labeling of new cells using BrdU, and in vivo labeling of new cells using a transgenic reporter system. We found that fetal alcohol exposure decreased the number of neural precursor cells in the subependymal zone and the number of new cells in the olfactory bulbs during the first few postnatal weeks. Using a combination of techniques, including structural brain imaging, in vitro and in vivo cell detection methods, and behavioral testing, we found that fetal alcohol exposure results in smaller olfactory bulbs and impairments in odor discrimination that persist into adulthood. Furthermore, we found that these abnormalities in olfactory bulb structure and function may arise from deficits in the generation of new olfactory bulb neurons during early postnatal development.

Odorant Inhibition of the Olfactory Cyclic Nucleotide-gated Channel with a Native Molecular Assembly

PubMed Central

Chen, Tsung-Yu; Takeuchi, Hiroko; Kurahashi, Takashi

2006-01-01

Human olfaction comprises the opposing actions of excitation and inhibition triggered by odorant molecules. In olfactory receptor neurons, odorant molecules not only trigger a G-protein–coupled signaling cascade but also generate various mechanisms to fine tune the odorant-induced current, including a low-selective odorant inhibition of the olfactory signal. This wide-range olfactory inhibition has been suggested to be at the level of ion channels, but definitive evidence is not available. Here, we report that the cyclic nucleotide-gated (CNG) cation channel, which is a key element that converts odorant stimuli into electrical signals, is inhibited by structurally unrelated odorants, consistent with the expression of wide-range olfactory inhibition. Interestingly, the inhibitory effect was small in the homo-oligomeric CNG channel composed only of the principal channel subunit, CNGA2, but became larger in channels consisting of multiple types of subunits. However, even in the channel containing all native subunits, the potency of the suppression on the cloned CNG channel appeared to be smaller than that previously shown in native olfactory neurons. Nonetheless, our results further showed that odorant suppressions are small in native neurons if the subsequent molecular steps mediated by Ca2+ are removed. Thus, the present work also suggests that CNG channels switch on and off the olfactory signaling pathway, and that the on and off signals may both be amplified by the subsequent olfactory signaling steps. PMID:16940558

Expression and distribution of the intermediate filament protein nestin and other stem cell related molecules in the human olfactory epithelium.

PubMed

Minovi, Amir; Witt, Martin; Prescher, Andreas; Gudziol, Volker; Dazert, Stefan; Hatt, Hanns; Benecke, Heike

2010-02-01

The olfactory epithelium (OE) is unique in regenerating throughout life and thus is an attractive target for examining neurogenesis. The nestin protein was shown to be expressed in the OE of rodents and is suggested to be essentially involved in the process of regeneration. Here we report the expression and distribution of nestin in the human OE at RNA and protein level. Moreover, we analysed the expression profiles in dependence on age and olfactory capacity. After sinus surgery, biopsies were taken from the olfactory epithelium of 16 patients aged 20-80 years with documented differences in their olfactory function. Our studies revealed that nestin is constantly detectable in the apical protuberances of sustentacular cells within the human OE of healthy adults. Its expression is not dependent on age, but rather appears to be related to the olfactory function, as a comparison with specimens obtained from patients suffering either from persistent anosmia or hyposmia suggests. Particularly, in the course of dystrophy, often accompanied with impaired olfaction, nestin expression was occasionally decreased. Contrarily, the expression of the p75-NGFR protein, a marker for human OE basal cells, was not altered, indicating that at least in the tested samples olfactory impairment is not connected with abnormalities at the basal cell level. These observations emphasize an essential role of nestin for the process of regeneration, and also highlight this factor as a candidate marker for sustentacular cells in the human olfactory epithelium.

[Changes in olfaction during ageing and in certain neurodegenerative diseases: up-to-date].

PubMed

Bianchi, A-J; Guépet-Sordet, H; Manckoundia, P

2015-01-01

Olfaction is a complex sensory system, and increasing interest is being shown in the link between olfaction and cognition, notably in the elderly. In this literature review, we revisit the specific neurophysiological features of the olfactory system and odorants that lead to a durable olfactory memory and an emotional memory, for which the implicit component produces subconscious olfactory conditioning. Olfaction is known to affect cognitive abilities and mood. We also consider the impairment of olfactory function due to ageing and to neurodegenerative diseases, in particular Alzheimer's disease and Parkinson's disease, through anatomopathological changes in the peripheral and central olfactory structures. The high frequency of these olfactory disorders as well as their early occurrence in Alzheimer disease and Parkinson disease are in favour of their clinical detection in subjects suffering from these two neurodegenerative diseases. Finally, we analyse the impact of olfactory stimulation on cognitive performance and attention. Current observational data from studies in elderly patients with Alzheimer-type dementia are limited to multiple sensory stimulation methods, such as the Snoezelen method, and aromatherapy. These therapies have shown benefits for dementia-related mood and behaviour disorders in the short term, with few side effects. Since olfactory chemosensory stimulation may be beneficial, it may be proposed in patients with dementia, especially Alzheimer-type dementia, as a complementary or even alternative therapy to existing medical strategies. Copyright © 2014 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.

Identification of olfactory receptor genes in the Japanese grenadier anchovy Coilia nasus.

PubMed

Zhu, Guoli; Wang, Liangjiang; Tang, Wenqiao; Wang, Xiaomei; Wang, Cong

2017-01-01

Olfaction is essential for fish to detect odorant elements in the environment and plays a critical role in navigating, locating food and detecting predators. Olfactory function is produced by the olfactory transduction pathway and is activated by olfactory receptors (ORs) through the binding of odorant elements. Recently, four types of olfactory receptors have been identified in vertebrate olfactory epithelium, including main odorant receptors (MORs), vomeronasal type receptors (VRs), trace-amine associated receptors (TAARs) and formyl peptide receptors (FPRs). It has been hypothesized that migratory fish, which have the ability to perform spawning migration, use olfactory cues to return to natal rivers. Therefore, obtaining OR genes from migratory fish will provide a resource for the study of molecular mechanisms that underlie fish spawning migration behaviors. Previous studies of OR genes have mainly focused on genomic data, however little information has been gained at the transcript level. In this study, we identified the OR genes of an economically important commercial fish Coilia nasus through searching for olfactory epithelium transcriptomes. A total of 142 candidate MOR, 52 V2R/OlfC, 32 TAAR and two FPR putative genes were identified. In addition, through genomic analysis we identified several MOR genes containing introns, which is unusual for vertebrate MOR genes. The transcriptome-scale mining strategy proved to be fruitful in identifying large sets of OR genes from species whose genome information is unavailable. Our findings lay the foundation for further research into the possible molecular mechanisms underlying the spawning migration behavior in C. nasus .

Calmodulin as a downstream gene of octopamine-OAR α1 signalling mediates olfactory attraction in gregarious locusts.

PubMed

Xu, L; Li, L; Yang, P; Ma, Z

2017-02-01

The migratory locust (Locusta migratoria) shows aggregative traits in nymph marching bands and swarm formations through mutual olfactory attraction of conspecifics. However, olfactory preference in different nymph stages in gregarious locusts is not sufficiently explored. In this study, we found that the nymph olfactory preference for gregarious volatiles exhibited obvious variations at different developmental stages. The gregarious locusts show attractive response to conspecific volatiles from the third stadium. Transcriptome comparison between third- and fourth-stadium nymphs showed that the G protein-coupled receptor (GPCR) pathways are significantly enriched. Amongst the genes present in GPCR pathways, the expression level of calmodulin in locust brains significantly increased from the third- to the fourth-stadium nymphs. Amongst the four octopamine receptors (OARs) belonging to the GPCR family, only OAR α1 showed similar expression patterns to those of calmodulin, and knockdown of OAR α1 reduced the expression level of calmodulin. RNA interference of calmodulin decreased locomotion and induced the loss of olfactory attraction in gregarious locusts. Moreover, the activation of OAR α1 in calmodulin-knockdown locusts did not induce olfactory attraction of the nymphs to gregarious volatiles. Thus, calmodulin as a downstream gene of octopamine-OAR α1 (OA-OAR α1) signalling mediates olfactory attraction in gregarious locusts. Overall, this study provides novel insights into the mechanism of OA-OAR α1 signalling involved in olfactory attraction of gregarious locusts. © 2016 The Royal Entomological Society.

Functional identification and reconstitution of an odorant receptor in single olfactory neurons

PubMed Central

Touhara, Kazushige; Sengoku, Shintaro; Inaki, Koichiro; Tsuboi, Akio; Hirono, Junzo; Sato, Takaaki; Sakano, Hitoshi; Haga, Tatsuya

1999-01-01

The olfactory system is remarkable in its capacity to discriminate a wide range of odorants through a series of transduction events initiated in olfactory receptor neurons. Each olfactory neuron is expected to express only a single odorant receptor gene that belongs to the G protein coupled receptor family. The ligand–receptor interaction, however, has not been clearly characterized. This study demonstrates the functional identification of olfactory receptor(s) for specific odorant(s) from single olfactory neurons by a combination of Ca2+-imaging and reverse transcription–coupled PCR analysis. First, a candidate odorant receptor was cloned from a single tissue-printed olfactory neuron that displayed odorant-induced Ca2+ increase. Next, recombinant adenovirus-mediated expression of the isolated receptor gene was established in the olfactory epithelium by using green fluorescent protein as a marker. The infected neurons elicited external Ca2+ entry when exposed to the odorant that originally was used to identify the receptor gene. Experiments performed to determine ligand specificity revealed that the odorant receptor recognized specific structural motifs within odorant molecules. The odorant receptor-mediated signal transduction appears to be reconstituted by this two-step approach: the receptor screening for given odorant(s) from single neurons and the functional expression of the receptor via recombinant adenovirus. The present approach should enable us to examine not only ligand specificity of an odorant receptor but also receptor specificity and diversity for a particular odorant of interest. PMID:10097159

The essence of appetite: Does olfactory receptor variation play a role?

USDA-ARS?s Scientific Manuscript database

Olfactory receptors are G-protein coupled chemoreceptors expressed on millions of olfactory sensory neurons within the nasal cavity. These receptors detect environmental odorants and signal the brain regarding the location of feed, potential mates, and the presence of possible threats (e.g., predato...

[Oxidative metabolism of main and accessory olfactory bulbs, limpic system and hypothalamus during the estral cycle of the rat (author's transl)].

PubMed

Sánchez-Criado, J E

1979-06-01

The in vitro oxidative metabolism of hypothalamus, olfactory and limbic systems from female rats in the estrous cycle have been measured. The accessory olfactory bulb becomes most active during diestrous when the hypothalamus reaches its lowest values.

Voltage-Dependent Intrinsic Bursting in Olfactory Bulb Golgi Cells

ERIC Educational Resources Information Center

Pressler, R. Todd; Rozman, Peter A.; Strowbridge, Ben W.

2013-01-01

In the mammalian olfactory bulb (OB), local synaptic circuits modulate the evolving pattern of activity in mitral and tufted cells following olfactory sensory stimulation. GABAergic granule cells, the most numerous interneuron subtype in this brain region, have been extensively studied. However, classic studies using Golgi staining methods…

Changes of pressure and humidity affect olfactory function.

PubMed

Kuehn, Michael; Welsch, Heiko; Zahnert, Thomas; Hummel, Thomas

2008-03-01

The present study aimed at investigating the question whether olfactory function changes in relation to barometric pressure and humidity. Using climate chambers, odor threshold and discrimination for butanol were tested in 75 healthy volunteers under hypobaric and hyperbaric, and different humidity conditions. Among other effects, olfactory sensitivity at threshold level, but not suprathreshold odor discrimination, was impaired in a hypobaric compared to a hyperbaric milieu, and thresholds were lower in humid, compared to relatively dry conditions. In conclusion, environmental conditions modulate the sense of smell, and may, consecutively, influence results from olfactory tests.

Topographic mapping--the olfactory system.

PubMed

Imai, Takeshi; Sakano, Hitoshi; Vosshall, Leslie B

2010-08-01

Sensory systems must map accurate representations of the external world in the brain. Although the physical senses of touch and vision build topographic representations of the spatial coordinates of the body and the field of view, the chemical sense of olfaction maps discontinuous features of chemical space, comprising an extremely large number of possible odor stimuli. In both mammals and insects, olfactory circuits are wired according to the convergence of axons from sensory neurons expressing the same odorant receptor. Synapses are organized into distinctive spherical neuropils--the olfactory glomeruli--that connect sensory input with output neurons and local modulatory interneurons. Although there is a strong conservation of form in the olfactory maps of mammals and insects, they arise using divergent mechanisms. Olfactory glomeruli provide a unique solution to the problem of mapping discontinuous chemical space onto the brain.

Canine olfactory receptor gene polymorphism and its relation to odor detection performance by sniffer dogs.

PubMed

Lesniak, Anna; Walczak, Marta; Jezierski, Tadeusz; Sacharczuk, Mariusz; Gawkowski, Maciej; Jaszczak, Kazimierz

2008-01-01

The outstanding sensitivity of the canine olfactory system has been acknowledged by using sniffer dogs in military and civilian service for detection of a variety of odors. It is hypothesized that the canine olfactory ability is determined by polymorphisms in olfactory receptor (OR) genes. We investigated 5 OR genes for polymorphic sites which might affect the olfactory ability of service dogs in different fields of specific substance detection. All investigated OR DNA sequences proved to have allelic variants, the majority of which lead to protein sequence alteration. Homozygous individuals at 2 gene loci significantly differed in their detection skills from other genotypes. This suggests a role of specific alleles in odor detection and a linkage between single-nucleotide polymorphism and odor recognition efficiency.

Antennal olfactory sensilla responses to insect chemical repellents in the common bed bug, Cimex lectularius.

PubMed

Liu, Feng; Haynes, Kenneth F; Appel, Arthur G; Liu, Nannan

2014-06-01

Populations of the common bed bug Cimex lectularius (Hemiptera; Cimicidae), a temporary ectoparasite on both humans and animals, have surged in many developed countries. Similar to other haematophagous arthropods, C. lectularius relies on its olfactory system to detect semiochemicals in the environment, including both attractants and repellents. To elucidate the olfactory responses of the common bed bug to commonly used insect chemical repellents, particularly haematophagous repellents, we investigated the neuronal responses of individual olfactory sensilla in C. lectularius' antennae to 52 insect chemical repellents, both synthetic and botanic. Different types of sensilla displayed highly distinctive response profiles. While C sensilla did not respond to any of the insect chemical repellents, Dγ sensilla proved to be the most sensitive in response to terpene-derived insect chemical repellents. Different chemical repellents elicited neuronal responses with differing temporal characteristics, and the responses of the olfactory sensilla to the insect chemical repellents were dose-dependent, with an olfactory response to the terpene-derived chemical repellent, but not to the non-terpene-derived chemical repellents. Overall, this study furnishes a comprehensive map of the olfactory response of bed bugs to commonly used insect chemical repellents, providing useful information for those developing new agents (attractants or repellents) for bed bug control.

Morphological study on the olfactory systems of the snapping turtle, Chelydra serpentina.

PubMed

Nakamuta, Nobuaki; Nakamuta, Shoko; Kato, Hideaki; Yamamoto, Yoshio

2016-06-01

In this study, the olfactory system of a semi-aquatic turtle, the snapping turtle, has been morphologically investigated by electron microscopy, immunohistochemistry, and lectin histochemistry. The nasal cavity of snapping turtle was divided into the upper and lower chambers, lined by the sensory epithelium containing ciliated and non-ciliated olfactory receptor neurons, respectively. Each neuron expressed both Gαolf, the α-subunit of G-proteins coupling to the odorant receptors, and Gαo, the α-subunit of G-proteins coupling to the type 2 vomeronasal receptors. The axons originating from the upper chamber epithelium projected to the ventral part of the olfactory bulb, while those from the lower chamber epithelium to the dorsal part of the olfactory bulb. Despite the identical expression of G-protein α-subunits in the olfactory receptor neurons, these two projections were clearly distinguished from each other by the differential expression of glycoconjugates. In conclusion, these data indicate the presence of two types of olfactory systems in the snapping turtle. Topographic arrangement of the upper and lower chambers and lack of the associated glands in the lower chamber epithelium suggest their possible involvement in the detection of odorants: upper chamber epithelium in the air and the lower chamber epithelium in the water. Copyright © 2016 Elsevier Ltd. All rights reserved.

Human olfaction: a constant state of change-blindness

PubMed Central

Sela, Lee

2010-01-01

Paradoxically, although humans have a superb sense of smell, they don’t trust their nose. Furthermore, although human odorant detection thresholds are very low, only unusually high odorant concentrations spontaneously shift our attention to olfaction. Here we suggest that this lack of olfactory awareness reflects the nature of olfactory attention that is shaped by the spatial and temporal envelopes of olfaction. Regarding the spatial envelope, selective attention is allocated in space. Humans direct an attentional spotlight within spatial coordinates in both vision and audition. Human olfactory spatial abilities are minimal. Thus, with no olfactory space, there is no arena for olfactory selective attention. Regarding the temporal envelope, whereas vision and audition consist of nearly continuous input, olfactory input is discreet, made of sniffs widely separated in time. If similar temporal breaks are artificially introduced to vision and audition, they induce “change blindness”, a loss of attentional capture that results in a lack of awareness to change. Whereas “change blindness” is an aberration of vision and audition, the long inter-sniff-interval renders “change anosmia” the norm in human olfaction. Therefore, attentional capture in olfaction is minimal, as is human olfactory awareness. All this, however, does not diminish the role of olfaction through sub-attentive mechanisms allowing subliminal smells a profound influence on human behavior and perception. PMID:20603708

Effects of isotretinoin on the olfactory function in patients with acne.

PubMed

Kartal, Demet; Yaşar, Mehmet; Kartal, Levent; Özcan, Ibrahim; Borlu, Murat

2017-01-01

Isotretinoin is a synthetic analog of vitamin A. Recent studies support a role for retinoic acid in the recovery of olfactory function following injury in mice. This study aimed at determining the effect of isotretinoin on olfactory function in patients who have acne and are otherwise healthy. Forty-five patients (aged 25-40 years) with acne were included in the study. All patients underwent a rhinological examination. Olfactory function was assessed by the Sniffin' Sticks Test. The test was assessed at baseline and in the third month of isotretinoin treatment. Isotretinoin improved the performance of patients in the olfactory test. The SST score increased from 8.7±1.09 to 9.5±1.19 (p<0.001), prevalence of hyposmia decreased from 40% to 24% and normosmia increased from 60% to 75% (p=0.059). The percentage of patients whose olfactory function was categorized as "good" increased from 6% to 21.3%. This increase was statistically significant (p<0.05). Absence of a control group is one of the limitations of this study. Also, we did not evaluate patients with smell test after stopping isotretinoin treatment. We examined the effect of systemic isotretinoin on olfactory function. It can be concluded from the present investigation that isotretinoin therapy improves the sense of smell.

Mixed input to olfactory glomeruli from two subsets of ciliated sensory neurons does not impede relay neuron specificity in the crucian carp.

PubMed

Hansson, Kenth-Arne; Døving, Kjell B; Skjeldal, Frode M

2015-10-01

The consensus view of olfactory processing is that the axons of receptor-specific primary olfactory sensory neurons (OSNs) converge to a small subset of glomeruli, thus preserving the odour identity before the olfactory information is processed in higher brain centres. In the present study, we show that two different subsets of ciliated OSNs with different odorant specificities converge to the same glomeruli. In order to stain different ciliated OSNs in the crucian carp Carassius carassius we used two different chemical odorants, a bile salt and a purported alarm substance, together with fluorescent dextrans. The dye is transported within the axons and stains glomeruli in the olfactory bulb. Interestingly, the axons from the ciliated OSNs co-converge to the same glomeruli. Despite intermingled innervation of glomeruli, axons and terminal fields from the two different subsets of ciliated OSNs remained mono-coloured. By 4-6 days after staining, the dye was transported trans-synaptically to separately stained axons of relay neurons. These findings demonstrate that specificity of the primary neurons is retained in the olfactory pathways despite mixed innervation of the olfactory glomeruli. The results are discussed in relation to the emerging concepts about non-mammalian glomeruli. © 2015. Published by The Company of Biologists Ltd.

A systematic review on olfaction in child and adolescent psychiatric disorders.

PubMed

Schecklmann, Martin; Schwenck, Christina; Taurines, Regina; Freitag, Christine; Warnke, Andreas; Gerlach, Manfred; Romanos, Marcel

2013-01-01

There is substantial evidence that olfactory function may serve as biomarker in adult neuropsychiatric disorders, e.g. overall diminished olfaction in Parkinson's disease as parameter for early pre-motor and differential diagnosis. Here, we present data from a systematic literature review in olfactory function in child and adolescent psychiatric disorders and report two unpublished data sets of autism and obsessive-compulsive disorder. The overall number of olfaction studies is low-even after taking into account adult samples. In addition, heterogeneity of findings is high due to methodological limitations such as the use of different olfactory tests and odours targeting the olfactory and/or the trigeminal system and neglecting possible confounders, e.g., intelligence or oto-rhino-laryngological affections. Despite these limitations, there is some indication for specific alterations of olfactory function especially in disorders with dopaminergic pathology (e.g. attention deficit/hyperactivity disorder, autism, schizophrenia, 22q11 deletion syndrome). Dopamine is a relevant modulator of early processes in the olfactory bulb. Our systematic review provides the basis for future confirmatory studies investigating olfaction as putative biomarker in child and adolescent psychiatric disorders. We further propose studies of thorough and elaborate methodological standards in combination with imaging techniques and the investigation of the influence of genetic variation on olfactory function.

Olfactory Nerve—A Novel Invasion Route of Neisseria meningitidis to Reach the Meninges

PubMed Central

Sjölinder, Hong; Jonsson, Ann-Beth

2010-01-01

Neisseria meningitidis is a human-specific pathogen with capacity to cause septic shock and meningitis. It has been hypothesized that invasion of the central nervous system (CNS) is a complication of a bacteremic condition. In this study, we aimed to characterize the invasion route of N. meningitidis to the CNS. Using an intranasally challenged mouse disease model, we found that twenty percent of the mice developed lethal meningitis even though no bacteria could be detected in blood. Upon bacterial infection, epithelial lesions and redistribution of intracellular junction protein N-cadherin were observed at the nasal epithelial mucosa, especially at the olfactory epithelium, which is functionally and anatomically connected to the CNS. Bacteria were detected in the submucosa of the olfactory epithelium, along olfactory nerves in the cribriform plate, at the olfactory bulb and subsequently at the meninges and subarachnoid space. Furthermore, our data suggest that a threshold level of bacteremia is required for the development of meningococcal sepsis. Taken together, N. meningitidis is able to pass directly from nasopharynx to meninges through the olfactory nerve system. This study enhances our understanding how N. meningitidis invades the meninges. The nasal olfactory nerve system may be a novel target for disease prevention that can improve outcome and survival. PMID:21124975

Olfactory nerve--a novel invasion route of Neisseria meningitidis to reach the meninges.

PubMed

Sjölinder, Hong; Jonsson, Ann-Beth

2010-11-18

Neisseria meningitidis is a human-specific pathogen with capacity to cause septic shock and meningitis. It has been hypothesized that invasion of the central nervous system (CNS) is a complication of a bacteremic condition. In this study, we aimed to characterize the invasion route of N. meningitidis to the CNS. Using an intranasally challenged mouse disease model, we found that twenty percent of the mice developed lethal meningitis even though no bacteria could be detected in blood. Upon bacterial infection, epithelial lesions and redistribution of intracellular junction protein N-cadherin were observed at the nasal epithelial mucosa, especially at the olfactory epithelium, which is functionally and anatomically connected to the CNS. Bacteria were detected in the submucosa of the olfactory epithelium, along olfactory nerves in the cribriform plate, at the olfactory bulb and subsequently at the meninges and subarachnoid space. Furthermore, our data suggest that a threshold level of bacteremia is required for the development of meningococcal sepsis. Taken together, N. meningitidis is able to pass directly from nasopharynx to meninges through the olfactory nerve system. This study enhances our understanding how N. meningitidis invades the meninges. The nasal olfactory nerve system may be a novel target for disease prevention that can improve outcome and survival.

Simultaneous Loss of NCKX4 and CNG Channel Desensitization Impairs Olfactory Sensitivity.

PubMed

Ferguson, Christopher H; Zhao, Haiqing

2017-01-04

In vertebrate olfactory sensory neurons (OSNs), Ca 2+ plays key roles in both mediating and regulating the olfactory response. Ca 2+ enters OSN cilia during the response through the olfactory cyclic nucleotide-gated (CNG) channel and stimulates a depolarizing chloride current by opening the olfactory Ca 2+ -activated chloride channel to amplify the response. Ca 2+ also exerts negative regulation on the olfactory transduction cascade, through mechanisms that include reducing the CNG current by desensitizing the CNG channel via Ca 2+ /calmodulin (CaM), to reduce the response. Ca 2+ is removed from the cilia primarily by the K + -dependent Na + /Ca 2+ exchanger 4 (NCKX4), and the removal of Ca 2+ leads to closure of the chloride channel and response termination. In this study, we investigate how two mechanisms conventionally considered negative regulatory mechanisms of olfactory transduction, Ca 2+ removal by NCKX4, and desensitization of the CNG channel by Ca 2+ /CaM, interact to regulate the olfactory response. We performed electro-olfactogram (EOG) recordings on the double-mutant mice, NCKX4 -/- ;CNGB1 ΔCaM , which are simultaneously lacking NCKX4 (NCKX4 -/- ) and Ca 2+ /CaM-mediated CNG channel desensitization (CNGB1 ΔCaM ). Despite exhibiting alterations in various response attributes, including termination kinetics and adaption properties, OSNs in either NCKX4 -/- mice or CNGB1 ΔCaM mice show normal resting sensitivity, as determined by their unchanged EOG response amplitude. We found that OSNs in NCKX4 -/- ;CNGB1 ΔCaM mice displayed markedly reduced EOG amplitude accompanied by alterations in other response attributes. This study suggests that what are conventionally considered negative regulatory mechanisms of olfactory transduction also play a role in setting the resting sensitivity in OSNs. Sensory receptor cells maintain high sensitivity at rest. Although the mechanisms responsible for setting the resting sensitivity of sensory receptor cells are not well understood, it has generally been assumed that the sensitivity is set primarily by how effectively the components in the activation cascade of sensory transduction can be stimulated. Our findings in mouse olfactory sensory neurons suggest that mechanisms that are primarily responsible for terminating the olfactory response are also critical for proper resting sensitivity. Copyright © 2017 the authors 0270-6474/17/370110-10$15.00/0.

Bioelectronic nose and its application to smell visualization.

PubMed

Ko, Hwi Jin; Park, Tai Hyun

2016-01-01

There have been many trials to visualize smell using various techniques in order to objectively express the smell because information obtained from the sense of smell in human is very subjective. So far, well-trained experts such as a perfumer, complex and large-scale equipment such as GC-MS, and an electronic nose have played major roles in objectively detecting and recognizing odors. Recently, an optoelectronic nose was developed to achieve this purpose, but some limitations regarding the sensitivity and the number of smells that can be visualized still persist. Since the elucidation of the olfactory mechanism, numerous researches have been accomplished for the development of a sensing device by mimicking human olfactory system. Engineered olfactory cells were constructed to mimic the human olfactory system, and the use of engineered olfactory cells for smell visualization has been attempted with the use of various methods such as calcium imaging, CRE reporter assay, BRET, and membrane potential assay; however, it is not easy to consistently control the condition of cells and it is impossible to detect low odorant concentration. Recently, the bioelectronic nose was developed, and much improved along with the improvement of nano-biotechnology. The bioelectronic nose consists of the following two parts: primary transducer and secondary transducer. Biological materials as a primary transducer improved the selectivity of the sensor, and nanomaterials as a secondary transducer increased the sensitivity. Especially, the bioelectronic noses using various nanomaterials combined with human olfactory receptors or nanovesicles derived from engineered olfactory cells have a potential which can detect almost all of the smells recognized by human because an engineered olfactory cell might be able to express any human olfactory receptor as well as can mimic human olfactory system. Therefore, bioelectronic nose will be a potent tool for smell visualization, but only if two technologies are completed. First, a multi-channel array-sensing system has to be applied for the integration of all of the olfactory receptors into a single chip for mimicking the performance of human nose. Second, the processing technique of the multi-channel system signals should be simultaneously established with the conversion of the signals to visual images. With the use of this latest sensing technology, the realization of a proper smell-visualization technology is expected in the near future.

Pelvic floor dysfunction: women's sexual concerns unraveled.

PubMed

Roos, Anne-Marie; Thakar, Ranee; Sultan, Abdul H; Burger, Curt W; Paulus, Aggie T G

2014-03-01

Sexual function of women suffering from pelvic organ prolapse (POP) and/or urinary incontinence (UI) is adversely affected. However, our current understanding of the exact relationship between female sexual dysfunction and POP and/or UI is incomplete. A qualitative study can improve our understanding by describing what women themselves perceive as the real problem. To gain a more in-depth understanding of the impact of POP and/or UI on the different categories of female sexual dysfunction by way of a qualitative study. Qualitative semistructured interviews were conducted in 37 women scheduled for pelvic floor surgery, and one was excluded from analysis due to incomplete recordings. The impact of POP and/or UI on female sexual function. Only 17% of women were completely positive about their sex life. Both POP and UI had a negative effect on body image. Women with POP had a negative image of their vagina, which caused them to be insecure about their partner's sexual experience, while women with UI were embarrassed about their incontinence and pad use, and feared smelling of urine. Worries about the presence of POP during sexual activity, discomfort from POP, and reduced genital sensations were the most important reasons for decreased desire, arousal, and difficulty reaching an orgasm in women with POP. Fear of incontinence during intercourse affected desire, arousal, and orgasm and could be a cause for dyspareunia in women with UI. Desire was divided into two main elements: "drive" and "motivation." Although "drive," i.e., spontaneous sexual interest, was not commonly affected by POP and/or UI, a decrease in "motivation" or the willingness to engage in sexual activity was the most common sexual dysfunction mentioned. Body image plays a key role in the sexual functioning of women with POP and/or UI with the biggest impact on women's "motivation." © 2013 International Society for Sexual Medicine.

Accuracy of self-report in detecting taste dysfunction.

PubMed

Soter, Ana; Kim, John; Jackman, Alexis; Tourbier, Isabelle; Kaul, Arti; Doty, Richard L

2008-04-01

To determine the sensitivity, specificity, and positive and negative predictive value of responses to the following questionnaire statements in detecting taste loss: "I can detect salt in chips, pretzels, or salted nuts," "I can detect sourness in vinegar, pickles, or lemon," "I can detect sweetness in soda, cookies, or ice cream," and "I can detect bitterness, in coffee, beer, or tonic water." Responses to an additional item, "I can detect chocolate in cocoa, cake or candy," was examined to determine whether patients clearly differentiate between taste loss and flavor loss secondary to olfactory dysfunction. A total of 469 patients (207 men, mean age = 54 years, standard deviation = 15 years; and 262 women, mean age = 54 years, standard deviation = 14 years) were administered a questionnaire containing these questions with the response categories of "easily," "somewhat," and "not at all," followed by a comprehensive taste and smell test battery. The questionnaire items poorly detected bona fide taste problems. However, they were sensitive in detecting persons without such problems (i.e., they exhibited low positive but high negative predictive value). Dysfunction categories of the University of Pennsylvania Smell Identification Test (UPSIT) were not meaningfully related to subjects' responses to the questionnaire statements. Both sex and age influenced performance on most of the taste tests, with older persons performing more poorly than younger ones and women typically outperforming men. Although it is commonly assumed that straight-forward questions concerning taste may be useful in detecting taste disorders, this study suggests this is not the case. However, patients who specifically report having no problems with taste perception usually do not exhibit taste dysfunction. The difficulty in detecting true taste problems by focused questionnaire items likely reflects a combination of factors. These include the relatively low prevalence of taste deficits in the general population and the tendency of patients to confuse loss of olfaction-related flavor sensations with taste-bud mediated deficits.

Incidental Lewy Body Disease: Clinical Comparison to a Control Cohort

PubMed Central

Adler, Charles H.; Connor, Donald J.; Hentz, Joseph G.; Sabbagh, Marwan N.; Caviness, John N.; Shill, Holly A.; Noble, Brie; Beach, Thomas G.

2010-01-01

Limited clinical information has been published on cases pathologically diagnosed with incidental Lewy body disease (ILBD). Standardized, longitudinal movement and cognitive data was collected on a cohort of subjects enrolled in the Sun Health Research Institute Brain and Body Donation Program. Of 277 autopsied subjects who had antemortem clinical evaluations within the previous 3 years, 76 did not have Parkinson’s disease, a related disorder, or dementia of which 15 (20%) had ILBD. Minor extrapyramidal signs were common in subjects with and without ILBD. Cognitive testing revealed an abnormality in the ILBD group in the Trails B test only. ILBD cases had olfactory dysfunction; however, sample size was very small. This preliminary report revealed ILBD cases have movement and cognitive findings that for the most part were not out of proportion to similarly assessed and age-similar cases without Lewy bodies. Larger sample size is needed to have the power to better assess group differences. PMID:20175211

Brain architecture in the terrestrial hermit crab Coenobita clypeatus (Anomura, Coenobitidae), a crustacean with a good aerial sense of smell

PubMed Central

Harzsch, Steffen; Hansson, Bill S

2008-01-01

Background During the evolutionary radiation of Crustacea, several lineages in this taxon convergently succeeded in meeting the physiological challenges connected to establishing a fully terrestrial life style. These physiological adaptations include the need for sensory organs of terrestrial species to function in air rather than in water. Previous behavioral and neuroethological studies have provided solid evidence that the land hermit crabs (Coenobitidae, Anomura) are a group of crustaceans that have evolved a good sense of aerial olfaction during the conquest of land. We wanted to study the central olfactory processing areas in the brains of these organisms and to that end analyzed the brain of Coenobita clypeatus (Herbst, 1791; Anomura, Coenobitidae), a fully terrestrial tropical hermit crab, by immunohistochemistry against synaptic proteins, serotonin, FMRFamide-related peptides, and glutamine synthetase. Results The primary olfactory centers in this species dominate the brain and are composed of many elongate olfactory glomeruli. The secondary olfactory centers that receive an input from olfactory projection neurons are almost equally large as the olfactory lobes and are organized into parallel neuropil lamellae. The architecture of the optic neuropils and those areas associated with antenna two suggest that C. clypeatus has visual and mechanosensory skills that are comparable to those of marine Crustacea. Conclusion In parallel to previous behavioral findings of a good sense of aerial olfaction in C. clypeatus, our results indicate that in fact their central olfactory pathway is most prominent, indicating that olfaction is a major sensory modality that these brains process. Interestingly, the secondary olfactory neuropils of insects, the mushroom bodies, also display a layered structure (vertical and medial lobes), superficially similar to the lamellae in the secondary olfactory centers of C. clypeatus. More detailed analyses with additional markers will be necessary to explore the question if these similarities have evolved convergently with the establishment of superb aerial olfactory abilities or if this design goes back to a shared principle in the common ancestor of Crustacea and Hexapoda. PMID:18590553

Fetal alcohol exposure leads to abnormal olfactory bulb development and impaired odor discrimination in adult mice

PubMed Central

2011-01-01

Background Children whose mothers consumed alcohol during pregnancy exhibit widespread brain abnormalities and a complex array of behavioral disturbances. Here, we used a mouse model of fetal alcohol exposure to investigate relationships between brain abnormalities and specific behavioral alterations during adulthood. Results Mice drank a 10% ethanol solution throughout pregnancy. When fetal alcohol-exposed offspring reached adulthood, we used high resolution MRI to conduct a brain-wide screen for structural changes and found that the largest reduction in volume occurred in the olfactory bulbs. Next, we tested adult mice in an associative olfactory task and found that fetal alcohol exposure impaired discrimination between similar odors but left odor memory intact. Finally, we investigated olfactory bulb neurogenesis as a potential mechanism by performing an in vitro neurosphere assay, in vivo labeling of new cells using BrdU, and in vivo labeling of new cells using a transgenic reporter system. We found that fetal alcohol exposure decreased the number of neural precursor cells in the subependymal zone and the number of new cells in the olfactory bulbs during the first few postnatal weeks. Conclusions Using a combination of techniques, including structural brain imaging, in vitro and in vivo cell detection methods, and behavioral testing, we found that fetal alcohol exposure results in smaller olfactory bulbs and impairments in odor discrimination that persist into adulthood. Furthermore, we found that these abnormalities in olfactory bulb structure and function may arise from deficits in the generation of new olfactory bulb neurons during early postnatal development. PMID:21736737

Olfactory discrimination ability and brain expression of c-fos, Gir and Glut1 mRNA are altered in n-3 fatty acid-depleted rats.

PubMed

Hichami, Aziz; Datiche, Frédérique; Ullah, Sana; Liénard, Fabienne; Chardigny, Jean-Michel; Cattarelli, Martine; Khan, Naim Akhtar

2007-11-22

The long-chain polyunsaturated n-3 fatty acids (n-3 PUFA), particularly docosahexaenoic acid (DHA), are abundantly present in the central nervous system and play an important role in cognitive functions such as learning and memory. We, therefore, investigated the effects of n-3 PUFA-depletion in rats (F2 generation) on the learning of an olfactory discrimination task, progressively acquired within a four-arm maze, and on the mRNA expression of some candidate genes, i.e., c-fos, Gir and glucose transporter (Glut1), which could reflect the level of cerebral activity. We observed that DHA contents were dramatically decreased in the olfactory bulb, the piriform cortex and the neocortex of n-3-depleted rats. Furthermore, the n-3 deficiency resulted in a mild olfactory learning impairment as these rats required more days to master the olfactory task compared to control rats. Real-time RT-PCR experiments revealed that the training induced the expression of c-fos mRNA in all the three regions of the brain whereas Gir and Glut1 mRNA were induced only in olfactory bulb and neocortex. However, such an increase was less marked in the n-3-deficient rats. Taken together, these results allow us to assume that the behavioural impairment in n-3-deficient rats is linked to the depletion of n-3 fatty acids in brain regions processing olfactory cues. Data are discussed in view of the possible role of some of these genes in learning-induced neuronal olfactory plasticity.

Ethmoidectomy combined with superior meatus enlargement increases olfactory airflow

PubMed Central

Kondo, Kenji; Nomura, Tsutomu; Yamasoba, Tatsuya

2017-01-01

Objectives The relationship between a particular surgical technique in endoscopic sinus surgery (ESS) and airflow changes in the post‐operative olfactory region has not been assessed. The present study aimed to compare olfactory airflow after ESS between conventional ethmoidectomy and ethmoidectomy with superior meatus enlargement, using virtual ESS and computational fluid dynamics (CFD) analysis. Study Design Prospective computational study. Materials and Methods Nasal computed tomography images of four adult subjects were used to generate models of the nasal airway. The original preoperative model was digitally edited as virtual ESS by performing uncinectomy, ethmoidectomy, antrostomy, and frontal sinusotomy. The following two post‐operative models were prepared: conventional ethmoidectomy with normal superior meatus (ESS model) and ethmoidectomy with superior meatus enlargement (ESS‐SM model). The calculated three‐dimensional nasal geometries were confirmed using virtual endoscopy to ensure that they corresponded to the post‐operative anatomy observed in the clinical setting. Steady‐state, laminar, inspiratory airflow was simulated, and the velocity, streamline, and mass flow rate in the olfactory region were compared among the preoperative and two postoperative models. Results The mean velocity in the olfactory region, number of streamlines bound to the olfactory region, and mass flow rate were higher in the ESS‐SM model than in the other models. Conclusion We successfully used an innovative approach involving virtual ESS, virtual endoscopy, and CFD to assess postoperative outcomes after ESS. It is hypothesized that the increased airflow to the olfactory fossa achieved with ESS‐SM may lead to improved olfactory function; however, further studies are required. Level of Evidence NA. PMID:28894833

Improving intranasal delivery of neurological nanomedicine to the olfactory region using magnetophoretic guidance of microsphere carriers

PubMed Central

Xi, Jinxiang; Zhang, Ze; Si, Xiuhua A

2015-01-01

Background Although direct nose-to-brain drug delivery has multiple advantages, its application is limited by the extremely low delivery efficiency (<1%) to the olfactory region where drugs can enter the brain. It is crucial to developing new methods that can deliver drug particles more effectively to the olfactory region. Materials and methods We introduced a delivery method that used magnetophoresis to improve olfactory delivery efficiency. The performance of the proposed method was assessed numerically in an image-based human nose model. Influences of the magnet layout, magnet strength, drug-release position, and particle diameter on the olfactory dosage were examined. Results and discussion Results showed that particle diameter was a critical factor in controlling the motion of nasally inhaled ferromagnetic drug particles. The optimal particle size was found to be approximately 15 μm for effective magnetophoretic guidance while avoiding loss of particles to the walls in the anterior nose. Olfactory delivery efficiency was shown to be sensitive to the position and strength of magnets and the release position of drug particles. The results of this study showed that clinically significant olfactory doses (up to 45%) were feasible using the optimal combination of magnet layout, selective drug release, and microsphere-carrier diameter. A 64-fold-higher delivery of dosage was predicted in the magnetized nose compared to the control case, which did not have a magnetic field. However, the sensitivity of olfactory dosage to operating conditions and the unstable nature of magnetophoresis make controlled guidance of nasally inhaled aerosols still highly challenging. PMID:25709443

Two Parallel Olfactory Pathways for Processing General Odors in a Cockroach

PubMed Central

Watanabe, Hidehiro; Nishino, Hiroshi; Mizunami, Makoto; Yokohari, Fumio

2017-01-01

In animals, sensory processing via parallel pathways, including the olfactory system, is a common design. However, the mechanisms that parallel pathways use to encode highly complex and dynamic odor signals remain unclear. In the current study, we examined the anatomical and physiological features of parallel olfactory pathways in an evolutionally basal insect, the cockroach Periplaneta americana. In this insect, the entire system for processing general odors, from olfactory sensory neurons to higher brain centers, is anatomically segregated into two parallel pathways. Two separate populations of secondary olfactory neurons, type1 and type2 projection neurons (PNs), with dendrites in distinct glomerular groups relay olfactory signals to segregated areas of higher brain centers. We conducted intracellular recordings, revealing olfactory properties and temporal patterns of both types of PNs. Generally, type1 PNs exhibit higher odor-specificities to nine tested odorants than type2 PNs. Cluster analyses revealed that odor-evoked responses were temporally complex and varied in type1 PNs, while type2 PNs exhibited phasic on-responses with either early or late latencies to an effective odor. The late responses are 30–40 ms later than the early responses. Simultaneous intracellular recordings from two different PNs revealed that a given odor activated both types of PNs with different temporal patterns, and latencies of early and late responses in type2 PNs might be precisely controlled. Our results suggest that the cockroach is equipped with two anatomically and physiologically segregated parallel olfactory pathways, which might employ different neural strategies to encode odor information. PMID:28529476

No Sensory Compensation for Olfactory Memory: Differences between Blind and Sighted People.

PubMed

Sorokowska, Agnieszka; Karwowski, Maciej

2017-01-01

Blindness can be a driving force behind a variety of changes in sensory systems. When vision is missing, other modalities and higher cognitive functions can become hyper-developed through a mechanism called sensory compensation. Overall, previous studies suggest that olfactory memory in blind people can be better than that of the sighted individuals. Better performance of blind individuals in other-sensory modalities was hypothesized to be a result of, among others, intense perceptual training. At the same time, if the superiority of blind people in olfactory abilities indeed results from training, their scores should not decrease with age to such an extent as among the sighted people. Here, this hypothesis was tested in a large sample of 94 blind individuals. Olfactory memory was assessed using the Test for Olfactory Memory, comprising episodic odor recognition (discriminating previously presented odors from new odors) and two forms of semantic memory (cued and free identification of odors). Regarding episodic olfactory memory, we observed an age-related decline in correct hits in blind participants, but an age-related increase in false alarms in sighted participants. Further, age moderated the between-group differences for correct hits, but the direction of the observed effect was contrary to our expectations. The difference between blind and sighted individuals younger than 40 years old was non-significant, but older sighted individuals outperformed their blind counterparts. In conclusion, we found no positive effect of visual impairment on olfactory memory. We suggest that daily perceptual training is not enough to increase olfactory memory function in blind people.

Dopaminergic Lesion in the Olfactory Bulb Restores Olfaction and Induces Depressive-Like Behaviors in a 6-OHDA Model of Parkinson's Disease.

PubMed

Ilkiw, Jessica L; Kmita, Luana C; Targa, Adriano D S; Noseda, Ana Carolina D; Rodrigues, Lais S; Dorieux, Flávia W C; Fagotti, Juliane; Dos Santos, Patrícia; Lima, Marcelo M S

2018-06-05

Olfactory impairments and depressive behavior are commonly reported by individuals with Parkinson's disease (PD) being observed before motor symptoms. The mechanisms underlying these clinical manifestations are not fully elucidated. However, the imbalance in dopaminergic neurotransmission seems to play an important role in this context. In patients and animal models of PD, an increase in the dopaminergic interneurons of the glomerular layer in olfactory bulb (OB-gl) is observed, which may contribute to the olfactory impairment. In addition, neuronal imbalance in OB is related to depressive symptoms, as demonstrated by chemical olfactory bulbectomy. In view of that, we hypothesized that a reduction in the number or density of dopaminergic neurons present in OB could promote an olfactory improvement and, in contrast, would accentuate the depressive-like behaviors in the 6-hydroxydopamine (6-OHDA) model of PD. Therefore, we performed single or double injections of 6-OHDA within the substantia nigra pars compacta (SNpc) and/or in the OB-gl. We observed that, after 7 days, the group with nigral lesion exhibited olfactory impairment, as well as the group with the lesion in the OB-gl. However, the combination of the lesions prevented the occurrence of hyposmia. In relation to depressive-like behaviors, we observed that the SNpc injury promoted depressive-like behavior, being accentuated after a double injury. Our results demonstrated the importance of the dopaminergic neurons of the OB-gl in different non-motor features of PD, since the selective reduction of these periglomerular neurons was able to induce olfactory impairment and depressive-like behaviors.

Expression of Olfactory Signaling Genes in the Eye

PubMed Central

Velmeshev, Dmitry; Faghihi, Mohammad; Shestopalov, Valery I.; Slepak, Vladlen Z.

2014-01-01

Purpose To advance our understanding how the outer eye interacts with its environment, we asked which cellular receptors are expressed in the cornea, focusing on G protein-coupled receptors. Methods Total RNA from the mouse cornea was subjected to next-generation sequencing using the Illumina platform. The data was analyzed with TopHat and CuffLinks software packages. Expression of a representative group of genes detected by RNA-seq was further analyzed by RT-PCR and in situ hybridization using RNAscope technology and fluorescent microscopy. Results We generated more than 46 million pair-end reads from mouse corneal RNA. Bioinformatics analysis revealed that the mouse corneal transcriptome reconstructed from these reads represents over 10,000 gene transcripts. We identified 194 GPCR transcripts, of which 96 were putative olfactory receptors. RT-PCR analysis confirmed the presence of several olfactory receptors and related genes, including olfactory marker protein and the G protein associated with olfaction, Gαolf. In situ hybridization showed that mRNA for olfactory marker protein, Gαolf and possibly some olfactory receptors were found in the corneal epithelial cells. In addition to the corneal epithelium, Gαolf was present in the ganglionic and inner nuclear layers of the retina. One of the olfactory receptors, Olfr558, was present primarily in vessels of the eye co-stained with antibodies against alpha-smooth muscle actin, indicating expression in arterioles. Conclusions Several species of mRNA encoding putative olfactory receptors and related genes are expressed in the mouse cornea and other parts of the eye indicating they may play a role in sensing chemicals in the ocular environment. PMID:24789354

Olfactory and cortical projections to bulbar and hippocampal adult-born neurons

PubMed Central

De La Rosa-Prieto, Carlos; De Moya-Pinilla, Miguel; Saiz-Sanchez, Daniel; Ubeda-banon, Isabel; Arzate, Dulce M.; Flores-Cuadrado, Alicia; Liberia, Teresa; Crespo, Carlos; Martinez-Marcos, Alino

2015-01-01

New neurons are continually generated in the subependymal layer of the lateral ventricles and the subgranular zone of dentate gyrus during adulthood. In the subventricular zone, neuroblasts migrate a long distance to the olfactory bulb where they differentiate into granule or periglomerular interneurons. In the hippocampus, neuroblasts migrate a short distance from the subgranular zone to the granule cell layer of the dentate gyrus to become granule neurons. In addition to the short-distance inputs, bulbar interneurons receive long-distance centrifugal afferents from olfactory-recipient structures. Similarly, dentate granule cells receive differential inputs from the medial and lateral entorhinal cortices through the perforant pathway. Little is known concerning these new inputs on the adult-born cells. In this work, we have characterized afferent inputs to 21-day old newly-born neurons. Mice were intraperitoneally injected with bromodeoxyuridine. Two weeks later, rhodamine-labeled dextran-amine was injected into the anterior olfactory nucleus, olfactory tubercle, piriform cortex and lateral and medial entorhinal cortices. One week later, animals were perfused and immunofluorescences were carried out. The data show that projection neurons from the mentioned structures, establish putative synaptic contacts onto 21-day-old neurons in the olfactory bulb and dentate gyrus, in some cases even before they start to express specific subpopulation proteins. Long-distance afferents reach middle and outer one-third portions of the molecular layer of the dentate gyrus and granule and, interestingly, periglomerular layers of the olfactory bulb. In the olfactory bulb, these fibers appear to establish presumptive axo-somatic contacts onto newly-born granule and periglomerular cells. PMID:25698936

Effect of ginkgo biloba and dexamethasone in the treatment of 3-methylindole-induced anosmia mouse model.

PubMed

Lee, Chul Hee; Mo, Ji-Hun; Shim, Seung Hee; Ahn, Jung-Min; Kim, Jeong-Whun

2008-01-01

Olfactory loss is a challenging disease. Although glucocorticoid is sometimes used for the treatment of anosmia, it has been reported that it potentiated neural damage in the early phase of treatment. This study is designed to identify the effect of ginkgo biloba, an antioxidant that acts as a free radical scavenger, in the treatment of olfactory injury aggravated by dexamethasone. Anosmia mouse model was induced by i.p. injection of 3-methylindole (3-MI). Twenty-five mice were divided into one control group without anosmia and four anosmia treatment groups (given treatments of dexamethasone and/or ginkgo biloba). The effects of treatment were evaluated by behavioral test, Western blot, and immunohistochemistry 2 weeks after 3-MI injection. Induction of anosmia was confirmed by behavioral tests. The thickness and cell number of olfactory neuroepithelium were decreased more significantly in the dexamethasone treatment group than in the combination treatment group. The expression of olfactory marker protein (OMP) in olfactory epithelium was more decreased also in the dexamethasone treatment group than in the combination treatment group. The expression of OMP was decreased significantly in the olfactory bulbs of anosmia groups but there were no differences between the anosmia treatment groups. Dexamethasone treatment was associated with further deterioration of olfactory injury by 3-MI and it was recovered by combination treatment of dexamethasone and ginkgo biloba. The antioxidant effect of ginkgo biloba might play a role in restoration of olfactory loss and it was effective only when oxidative stress is maximized by dexamethasone.

No Sensory Compensation for Olfactory Memory: Differences between Blind and Sighted People

PubMed Central

Sorokowska, Agnieszka; Karwowski, Maciej

2017-01-01

Blindness can be a driving force behind a variety of changes in sensory systems. When vision is missing, other modalities and higher cognitive functions can become hyper-developed through a mechanism called sensory compensation. Overall, previous studies suggest that olfactory memory in blind people can be better than that of the sighted individuals. Better performance of blind individuals in other-sensory modalities was hypothesized to be a result of, among others, intense perceptual training. At the same time, if the superiority of blind people in olfactory abilities indeed results from training, their scores should not decrease with age to such an extent as among the sighted people. Here, this hypothesis was tested in a large sample of 94 blind individuals. Olfactory memory was assessed using the Test for Olfactory Memory, comprising episodic odor recognition (discriminating previously presented odors from new odors) and two forms of semantic memory (cued and free identification of odors). Regarding episodic olfactory memory, we observed an age-related decline in correct hits in blind participants, but an age-related increase in false alarms in sighted participants. Further, age moderated the between-group differences for correct hits, but the direction of the observed effect was contrary to our expectations. The difference between blind and sighted individuals younger than 40 years old was non-significant, but older sighted individuals outperformed their blind counterparts. In conclusion, we found no positive effect of visual impairment on olfactory memory. We suggest that daily perceptual training is not enough to increase olfactory memory function in blind people. PMID:29276494

Evidence for Chemoreception in Squid Olfactory Organ

DTIC Science & Technology

1990-05-29

Positive Responses and Number of Trials Chemical %Positive #of Trials #of Animals 5mM Isethionate 0 (3) 1 5mM Betaine 0 (13) 1 5mM Menthol 0 (2) 1...that the olfactory organ is the site of high chemical sensitivity. Figure 3. Application of the local anesthetic betaine to the olfactory knob

Roles for Drosophila Mushroom Body Neurons in Olfactory Learning and Memory

ERIC Educational Resources Information Center

Zong, Lin; Tanaka, Nobuaki K.; Ito, Kei; Davis, Ronald L.; Akalal, David-Benjamin G.; Wilson, Curtis F.

2006-01-01

Olfactory learning assays in Drosophila have revealed that distinct brain structures known as mushroom bodies (MBs) are critical for the associative learning and memory of olfactory stimuli. However, the precise roles of the different neurons comprising the MBs are still under debate. The confusion surrounding the roles of the different neurons…

High hunger state increases olfactory sensitivity to neutral but not food odors.

PubMed

Stafford, Lorenzo D; Welbeck, Kimberley

2011-01-01

Understanding how hunger state relates to olfactory sensitivity has become more urgent due to their possible role in obesity. In 2 studies (within-subjects: n = 24, between-subjects: n = 40), participants were provided with lunch before (satiated state) or after (nonsatiated state) testing and completed a standardized olfactory threshold test to a neutral odor (Experiments 1 and 2) and discrimination test to a food odor (Experiment 2). Experiment 1 revealed that olfactory sensitivity was greater in the nonsatiated versus satiated state, with additionally increased sensitivity for the low body mass index (BMI) compared with high BMI group. Experiment 2 replicated this effect for neutral odors, but in the case of food odors, those in a satiated state had greater acuity. Additionally, whereas the high BMI group had higher acuity to food odors in the satiated versus nonsatiated state, no such differences were found for the low BMI group. The research here is the first to demonstrate how olfactory acuity changes as a function of hunger state and relatedness of odor to food and that BMI can predict differences in olfactory sensitivity.

FoxP2 and olfaction: divergence of FoxP2 expression in olfactory tubercle between different feeding habit bats.

PubMed

Chen, Qi; Wang, Lina; Jones, G; Metzner, W; Xuan, F J; Yin, Jiangxia; Sun, Y

2013-12-01

FoxP2 is a member of the winged helix/forkhead class of transcription factors. Despite FoxP2 is found to have particular relevance to speech and language, the role of this gene is broader and not yet fully elucidated. In this study, we investigated the expression of FoxP2 in the brains of bats with different feeding habits (two frugivorous species and three insectivorous species). We found FoxP2 expression in the olfactory tubercle of frugivorous species is significantly higher than that in insectivorous species. Difference of FoxP2 expression was not observed within each of the frugivorous or insectivorous group. The diverse expression patterns in olfactory tubercle between two kinds of bats indicate FoxP2 has a close relation with olfactory tubercle associated functions, suggesting its important role in sensory integration within the olfactory tubercle and such a discrepancy of FoxP2 expression in olfactory tubercle may take responsibility for the different feeding behaviors of frugivorous and insectivorous bats.

Stable olfactory sensory neuron in vivo physiology during normal aging.

PubMed

Kass, Marley D; Czarnecki, Lindsey A; McGann, John P

2018-05-08

Normal aging is associated with a number of smell impairments that are paralleled by age-dependent changes in the peripheral olfactory system, including decreases in olfactory sensory neurons (OSNs) and in the regenerative capacity of the epithelium. Thus, an age-dependent degradation of sensory input to the brain is one proposed mechanism for the loss of olfactory function in older populations. Here, we tested this hypothesis by performing in vivo optical neurophysiology in 6-, 12-, 18-, and 24-month-old mice. We visualized odor-evoked neurotransmitter release from populations of OSNs into olfactory bulb glomeruli, and found that these sensory inputs are actually quite stable during normal aging. Specifically, the magnitude and number of odor-evoked glomerular responses were comparable across all ages, and there was no effect of age on the sensitivity of OSN responses to odors or on the neural discriminability of different sensory maps. These results suggest that the brain's olfactory bulbs do not receive deteriorated input during aging and that local bulbar circuitry might adapt to maintain stable nerve input. Copyright © 2018 Elsevier Inc. All rights reserved.

Ontogenetic development of the nervus terminalis in toothed whales. Evidence for its non-olfactory nature.

PubMed

Buhl, E H; Oelschläger, H A

1986-01-01

For the first time in cetaceans, the development of the terminalis system and its continuity between the olfactory placode and the telencephalon has been demonstrated by light microscopy. In the early development of toothed whales (Odontoceti) this system is partially incorporated within the fila olfactoria which grow out from the olfactory placode. As the peripheral olfactory system is reduced in later stages, a strongly developed ganglionlike structure (terminalis ganglion) remains within the primitive meninx. Peripherally it is connected via the cribriform plate with ganglionic cell clusters near the septal mucosa. Centrally it is attached to the telencephalon (olfactory tubercle, septal region) by several nerve fibre bundles. In contrast to all other mammalian groups, toothed whales and dolphins are anosmatic while being totally adapted to aquatic life. Therefore the remaining ganglion and plexus must have non-olfactory properties. They may be responsible for the autonomic innervation of intracranial arteries and of the large mucous epithelia in the accessory nasal air sacs. The morphology, evolution and functional implications of the terminalis system in odontocetes and other mammals are discussed.

Evolution of the Genetic and Neural Architecture for Vertebrate Odor Perception

PubMed Central

Bear, Daniel M.; Lassance, Jean-Marc; Hoekstra, Hopi E.; Datta, Sandeep Robert

2016-01-01

Evolution sculpts the olfactory nervous system in response to the unique sensory challenges facing each species. In vertebrates, dramatic and diverse adaptations to the chemical environment are possible because of the hierarchical structure of the olfactory receptor (OR) gene superfamily: rapid growth or pruning across the OR gene tree accompany major changes in habitat and lifestyle; independent selection on OR subfamilies can permit local adaptation or conserved chemical communication; and genetic variation in single OR genes among thousands can alter odor percepts and behaviors driven by precise chemical cues. However, this genetic flexibility contrasts with the relatively fixed neural architecture of the vertebrate olfactory system, whose slower rate of divergence mandates that new olfactory receptors integrate into segregated and functionally-distinct neural pathways. This organization allows evolution to couple critical chemical signals with selectively advantageous responses, but also constrains relationships between olfactory receptors and behavior. The coevolution of the OR repertoire and the structure of the olfactory system therefore reveals general principles of how the brain solves specific sensory problems and how it adapts to new ones. PMID:27780046

Anosmia and Ageusia in Parkinson's Disease.

PubMed

Tarakad, Arjun; Jankovic, Joseph

2017-01-01

Anosmia, the loss of sense of smell, is a common nonmotor feature of Parkinson's disease (PD). Ageusia, the loss of sense of taste, is additionally an underappreciated nonmotor feature of PD. The olfactory tract is involved early in PD as indicated by frequent occurrence of hyposmia or anosmia years or decades before motor symptoms and by autopsy studies showing early synuclein pathology in the olfactory tract and anterior olfactory nucleus even in the early stages of PD. Testing for olfaction consists of evaluation of olfactory thresholds, smell identification and discrimination, and olfactory memory. Testing for gustation involves evaluating thresholds and discrimination of five basic tastes (salty, sweet, bitter, sour, and umami). The presence of a specific pattern of loss in both olfaction and gustation in PD has been proposed, but this has not yet been confirmed. Within PD, olfactory loss is strongly tied with cognitive status though links to other features of PD or a particular PD phenotype is debated. Hyposmia is more often present and typically more severe in PD patients than other parkinsonian syndromes, making it a potentially useful biomarker for the disease. © 2017 Elsevier Inc. All rights reserved.

Deciphering the function of the CNGB1b subunit in olfactory CNG channels.

PubMed

Nache, Vasilica; Wongsamitkul, Nisa; Kusch, Jana; Zimmer, Thomas; Schwede, Frank; Benndorf, Klaus

2016-07-11

Olfactory cyclic nucleotide-gated (CNG) ion channels are key players in the signal transduction cascade of olfactory sensory neurons. The second messengers cAMP and cGMP directly activate these channels, generating a depolarizing receptor potential. Olfactory CNG channels are composed of two CNGA2 subunits and two modulatory subunits, CNGA4, and CNGB1b. So far the exact role of the modulatory subunits for channel activation is not fully understood. By measuring ligand binding and channel activation simultaneously, we show that in functional heterotetrameric channels not only the CNGA2 subunits and the CNGA4 subunit but also the CNGB1b subunit binds cyclic nucleotides and, moreover, also alone translates this signal to open the pore. In addition, we show that the CNGB1b subunit is the most sensitive subunit in a heterotetrameric channel to cyclic nucleotides and that it accelerates deactivation to a similar extent as does the CNGA4 subunit. In conclusion, the CNGB1b subunit participates in ligand-gated activation of olfactory CNG channels and, particularly, contributes to rapid termination of odorant signal in an olfactory sensory neuron.

The Origin, Development and Molecular Diversity of Rodent Olfactory Bulb Glutamatergic Neurons Distinguished by Expression of Transcription Factor NeuroD1.

PubMed

Roybon, Laurent; Mastracci, Teresa L; Li, Joyce; Stott, Simon R W; Leiter, Andrew B; Sussel, Lori; Brundin, Patrik; Li, Jia-Yi

2015-01-01

Production of olfactory bulb neurons occurs continuously in the rodent brain. Little is known, however, about cellular diversity in the glutamatergic neuron subpopulation. In the central nervous system, the basic helix-loop-helix transcription factor NeuroD1 (ND1) is commonly associated with glutamatergic neuron development. In this study, we utilized ND1 to identify the different subpopulations of olfactory bulb glutamategic neurons and their progenitors, both in the embryo and postnatally. Using knock-in mice, transgenic mice and retroviral transgene delivery, we demonstrate the existence of several different populations of glutamatergic olfactory bulb neurons, the progenitors of which are ND1+ and ND1- lineage-restricted, and are temporally and regionally separated. We show that the first olfactory bulb glutamatergic neurons produced - the mitral cells - can be divided into molecularly diverse subpopulations. Our findings illustrate the complexity of neuronal diversity in the olfactory bulb and that seemingly homogenous neuronal populations can consist of multiple subpopulations with unique molecular signatures of transcription factors and expressing neuronal subtype-specific markers.

Olfactory mechanisms in the control of maternal aggression, appetite, and fearfulness: effects of lesions to olfactory receptors, mediodorsal thalamic nucleus, and insular prefrontal cortex.

PubMed

Ferreira, A; Dahlöf, L G; Hansen, S

1987-10-01

During lactation the female rat is hyperphagic, aggressive toward adult conspecifics, and less fearful than usual. In the first experiment the importance of olfactory receptors was investigated by surgically removing the olfactory epithelium of the nasal cavity. Mother rats subjected to this treatment consumed significantly less food and weighed less than sham-operated females. Moreover, experimental subjects displayed a dramatic decrease in maternal aggression. Fear behavior (sound-elicited freezing), on the other hand, was not affected by the lesions. The mediodorsal thalamic nucleus and the prefrontal insular cortex form part of the central olfactory system. The second experiment assessed the involvement of this olfactory-related thalamocortical system and the behavioral profile of mother rats. It was found that whereas the thalamic and cortical lesions left food intake and fear behavior unaffected, they significantly decreased the frequency with which the mother would attack an intruder male placed into her home cage. The sense of smell appears, according to the present experiments, to play a crucial role in maternal aggression.

Fish oil improves anxiety-like, depressive-like and cognitive behaviors in olfactory bulbectomised rats.

PubMed

Pudell, Claudia; Vicente, Bianca A; Delattre, Ana M; Carabelli, Bruno; Mori, Marco A; Suchecki, Deborah; Machado, Ricardo B; Zanata, Sílvio M; Visentainer, Jesuí V; de Oliveira Santos Junior, Oscar; Lima, Marcelo M S; Ferraz, Anete C

2014-01-01

Depression is increasingly present in the population, and its pathophysiology and treatment have been investigated with several animal models, including olfactory bulbectomy (Obx). Fish oil (FO) supplementation during the prenatal and postnatal periods decreases depression-like and anxiety-like behaviors. The present study evaluated the effect of FO supplementation on Obx-induced depressive-like behavior and cognitive impairment. Female rats received supplementation with FO during habituation, mating, gestation, and lactation, and their pups were subjected to Obx in adulthood; after the recovery period, the adult offspring were subjected to behavioral tests, and the hippocampal levels of brain-derived neurotrophic factor (BDNF), serotonin (5-HT) and the metabolite 5-hydroxyindoleacetic (5-HIAA) were determined. Obx led to increased anxiety-like and depressive-like behaviors, and impairment in the object location task. All behavioral changes were reversed by FO supplementation. Obx caused reductions in the levels of hippocampal BDNF and 5-HT, whereas FO supplementation restored these levels to normal values. In control rats, FO increased the hippocampal level of 5-HT and reduced that of 5-HIAA, indicating low 5-HT metabolism in this brain region. The present results indicate that FO supplementation during critical periods of brain development attenuated anxiety-like and depressive-like behaviors and cognitive dysfunction induced by Obx. These results may be explained by increased levels of hippocampal BDNF and 5-HT, two major regulators of neuronal survival and long-term plasticity in this brain structure. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Maternal depressive symptoms, dysfunctional cognitions, and infant night waking: the role of maternal nighttime behavior.

PubMed

Teti, Douglas M; Crosby, Brian

2012-01-01

Mechanisms were examined to clarify relations between maternal depressive symptoms, dysfunctional cognitions, and infant night waking among 45 infants (1-24 months) and their mothers. A mother-driven mediational model was tested in which maternal depressive symptoms and dysfunctional cognitions about infant sleep predicted infant night waking via their impact on mothers' bedtime and nighttime behavior with infants (from video). Two infant-driven mediational models were also examined, in which infant night waking predicted maternal depressive symptoms, or dysfunctional cognitions, via their impact on nighttime maternal behavior. Stronger support for the mother-driven model was obtained, which was further supported by qualitative observations from video-recordings. This study provides important insights about maternal depression's effects on nighttime parenting, and how such parenting affects infant sleep. © 2012 The Authors. Child Development © 2012 Society for Research in Child Development, Inc.

The styryl dye FM1-43 suppresses odorant responses in a subset of olfactory neurons by blocking cyclic nucleotide-gated (CNG) channels.

PubMed

Breunig, Esther; Kludt, Eugen; Czesnik, Dirk; Schild, Detlev

2011-08-12

Many olfactory receptor neurons use a cAMP-dependent transduction mechanism to transduce odorants into depolarizations. This signaling cascade is characterized by a sequence of two currents: a cation current through cyclic nucleotide-gated channels followed by a chloride current through calcium-activated chloride channels. To date, it is not possible to interfere with these generator channels under physiological conditions with potent and specific blockers. In this study we identified the styryl dye FM1-43 as a potent blocker of native olfactory cyclic nucleotide-gated channels. Furthermore, we characterized this substance to stain olfactory receptor neurons that are endowed with cAMP-dependent transduction. This allows optical differentiation and pharmacological interference with olfactory receptor neurons at the level of the signal transduction.

Opposite effects depending on learning and memory demands in dorsomedial prefrontal cortex lesioned rats performing an olfactory task.

PubMed

Chaillan, F A; Marchetti, E; Delfosse, F; Roman, F S; Soumireu-Mourat, B

1997-01-01

In this study, the functional properties of the dorsomedial prefrontal cortex (dmPFC) of the rat were examined in two olfactory tasks. In a successive cue olfactory discrimination task, dmPFC lesioned animals improved performance across sessions more rapidly than operated control animals. In an olfactory task using fixed interval training, animals with similar lesions were impaired. Both effects, although opposite, can be explained by a temporal processing deficit. The present results seem to indicate that the dmPFC is required for timing, classified as part of non-declarative memory. As reference memory improved in the lesioned animals, the finding is that the dmPFC supports non-declarative memory and thus interacts with declarative memory in the long-term formation of the associations between a particular stimulus (olfactory cue) and particular responses.

Human pheromones and sexual attraction.

PubMed

Grammer, Karl; Fink, Bernhard; Neave, Nick

2005-02-01

Olfactory communication is very common amongst animals, and since the discovery of an accessory olfactory system in humans, possible human olfactory communication has gained considerable scientific interest. The importance of the human sense of smell has by far been underestimated in the past. Humans and other primates have been regarded as primarily 'optical animals' with highly developed powers of vision but a relatively undeveloped sense of smell. In recent years this assumption has undergone major revision. Several studies indicate that humans indeed seem to use olfactory communication and are even able to produce and perceive certain pheromones; recent studies have found that pheromones may play an important role in the behavioural and reproduction biology of humans. In this article we review the present evidence of the effect of human pheromones and discuss the role of olfactory cues in human sexual behaviour.

Modeling Olfactory Bulb Evolution through Primate Phylogeny

PubMed Central

Heritage, Steven

2014-01-01

Adaptive characterizations of primates have usually included a reduction in olfactory sensitivity. However, this inference of derivation and directionality assumes an ancestral state of olfaction, usually by comparison to a group of extant non-primate mammals. Thus, the accuracy of the inference depends on the assumed ancestral state. Here I present a phylogenetic model of continuous trait evolution that reconstructs olfactory bulb volumes for ancestral nodes of primates and mammal outgroups. Parent-daughter comparisons suggest that, relative to the ancestral euarchontan, the crown-primate node is plesiomorphic and that derived reduction in olfactory sensitivity is an attribute of the haplorhine lineage. The model also suggests a derived increase in olfactory sensitivity at the strepsirrhine node. This oppositional diversification of the strepsirrhine and haplorhine lineages from an intermediate and non-derived ancestor is inconsistent with a characterization of graded reduction through primate evolution. PMID:25426851

A Computational Study of the Hydrodynamics in the Nasal Region of a Hammerhead Shark (Sphyrna tudes): Implications for Olfaction

PubMed Central

Rygg, Alex D.; Cox, Jonathan P. L.; Abel, Richard; Webb, Andrew G.; Smith, Nadine B.; Craven, Brent A.

2013-01-01

The hammerhead shark possesses a unique head morphology that is thought to facilitate enhanced olfactory performance. The olfactory chambers, located at the distal ends of the cephalofoil, contain numerous lamellae that increase the surface area for olfaction. Functionally, for the shark to detect chemical stimuli, water-borne odors must reach the olfactory sensory epithelium that lines these lamellae. Thus, odorant transport from the aquatic environment to the sensory epithelium is the first critical step in olfaction. Here we investigate the hydrodynamics of olfaction in Sphyrna tudes based on an anatomically-accurate reconstruction of the head and olfactory chamber from high-resolution micro-CT and MRI scans of a cadaver specimen. Computational fluid dynamics simulations of water flow in the reconstructed model reveal the external and internal hydrodynamics of olfaction during swimming. Computed external flow patterns elucidate the occurrence of flow phenomena that result in high and low pressures at the incurrent and excurrent nostrils, respectively, which induces flow through the olfactory chamber. The major (prenarial) nasal groove along the cephalofoil is shown to facilitate sampling of a large spatial extent (i.e., an extended hydrodynamic “reach”) by directing oncoming flow towards the incurrent nostril. Further, both the major and minor nasal grooves redirect some flow away from the incurrent nostril, thereby limiting the amount of fluid that enters the olfactory chamber. Internal hydrodynamic flow patterns are also revealed, where we show that flow rates within the sensory channels between olfactory lamellae are passively regulated by the apical gap, which functions as a partial bypass for flow in the olfactory chamber. Consequently, the hammerhead shark appears to utilize external (major and minor nasal grooves) and internal (apical gap) flow regulation mechanisms to limit water flow between the olfactory lamellae, thus protecting these delicate structures from otherwise high flow rates incurred by sampling a larger area. PMID:23555780

Effects of analgesics on olfactory function and the perception of intranasal trigeminal stimuli.

PubMed

Mizera, L; Gossrau, G; Hummel, T; Haehner, A

2017-01-01

There is some evidence suggesting that analgesics have an impact on human chemosensory function, especially opioids and cannabinoids are known to interfere with olfactory function. However, largely unknown is the effect of a long-term use of analgesics on the intranasal trigeminal system so far. Here, we investigated olfactory function and the perception of intranasal trigeminal stimuli in pain patients with long-term use of analgesics compared to age-matched healthy controls. For this purpose, a psychophysical approach was chosen to measure these sensory functions in 100 chronic pain patients and 95 controls. Olfactory testing was performed using the 'Sniffin' Sticks' test kit, which involves tests for odour threshold, odour discrimination and odour identification. Further, participants were asked to rate the intensity of trigeminal stimuli by using a visual analogue scale. We observed that the chronic use of pain medication was associated with significantly reduced perception of intranasal trigeminal stimuli and olfactory function compared to age-matched controls without intake of analgesics. Results indicate that non-opioid and opioid drugs, or a combination of both did not differ in their effects on chemosensory function. Further, after eliminating the effect of a co-existing depression and the use of co-analgesics, the negative influence of analgesics on olfactory function and trigeminal perception was still evident. The observed effect might be mediated due to interaction with opioid receptors in trigeminal ganglia and nuclei or due to trigeminal/olfactory interaction. As a practical consequence, patients should be made aware of a possible impairment of their olfactory and trigeminal function under long-term analgesic treatment. WHAT DOES THIS STUDY ADD?: We observed that the chronic use of pain medication was associated with significantly reduced olfactory function and perception of intranasal trigeminal stimuli compared to age-matched controls without intake of analgesics. Non-opioid and opioid drugs did not differ in their effects on chemosensory function. © 2016 European Pain Federation - EFIC®.

Multimodal Floral Signals and Moth Foraging Decisions

PubMed Central

Riffell, Jeffrey A.; Alarcón, Ruben

2013-01-01

Background Combinations of floral traits – which operate as attractive signals to pollinators – act on multiple sensory modalities. For Manduca sexta hawkmoths, how learning modifies foraging decisions in response to those traits remains untested, and the contribution of visual and olfactory floral displays on behavior remains unclear. Methodology/Principal Findings Using M. sexta and the floral traits of two important nectar resources in southwestern USA, Datura wrightii and Agave palmeri, we examined the relative importance of olfactory and visual signals. Natural visual and olfactory cues from D. wrightii and A. palmeri flowers permits testing the cues at their native intensities and composition – a contrast to many studies that have used artificial stimuli (essential oils, single odorants) that are less ecologically relevant. Results from a series of two-choice assays where the olfactory and visual floral displays were manipulated showed that naïve hawkmoths preferred flowers displaying both olfactory and visual cues. Furthermore, experiments using A. palmeri flowers – a species that is not very attractive to hawkmoths – showed that the visual and olfactory displays did not have synergistic effects. The combination of olfactory and visual display of D. wrightii, however – a flower that is highly attractive to naïve hawkmoths – did influence the time moths spent feeding from the flowers. The importance of the olfactory and visual signals were further demonstrated in learning experiments in which experienced moths, when exposed to uncoupled floral displays, ultimately chose flowers based on the previously experienced olfactory, and not visual, signals. These moths, however, had significantly longer decision times than moths exposed to coupled floral displays. Conclusions/Significance These results highlight the importance of specific sensory modalities for foraging hawkmoths while also suggesting that they learn the floral displays as combinatorial signals and use the integrated floral traits from their memory traces to mediate future foraging decisions. PMID:23991154

Differential effects of unilateral olfactory deprivation on noradrenergic and cholinergic systems in the main olfactory bulb of the rat.

PubMed

Gómez, C; Briñón, J G; Colado, M I; Orio, L; Vidal, M; Barbado, M V; Alonso, J R

2006-09-15

The lack of environmental olfactory stimulation produced by sensory deprivation causes significant changes in the deprived olfactory bulb. Olfactory transmission in the main olfactory bulb (MOB) is strongly modulated by centrifugal systems. The present report examines the effects of unilateral deprivation on the noradrenergic and cholinergic centrifugal systems innervating the MOB. The morphology, distribution, and density of positive axons were studied in the MOBs of control and deprived rats, using dopamine-beta-hydroxylase (DBH)-immunohistochemistry and acetylcholinesterase (AChE) histochemistry in serial sections. Catecholamine content was compared among the different groups of MOBs (control, contralateral, and ipsilateral to the deprivation) using high-performance liquid chromatography analysis. Sensory deprivation revealed that the noradrenergic system developed adaptive plastic changes after olfactory deprivation, including important modifications in its fiber density and distribution, while no differences in cholinergic innervation were observed under the same conditions. The noradrenergic system underwent an important alteration in the glomerular layer, in which some glomeruli showed a dense noradrenergic innervation that was not detected in control animals. The DBH-positive glomeruli with the highest noradrenergic fiber density were compared with AChE-stained sections and it was observed that the strongly noradrenergic-innervated glomeruli were always atypical glomeruli (characterized by their strong degree of cholinergic innervation). In addition to the morphological findings, our biochemical data revealed that olfactory deprivation caused a decrease in the content of dopamine and its metabolite 3,4-dihydroxyphenylacetic acid in the ipsilateral MOB in comparison to the contralateral and control MOBs, together with an increase in noradrenaline levels in both the ipsilateral and contralateral MOBs. Our results show that regulation of the noradrenergic centrifugal system in the MOB depends on environmental olfactory stimulation and that it is highly reactive to sensory deprivation. By contrast, the cholinergic system is fairly stable and does not exhibit clear changes after the loss of sensory inputs.

Quantitative comparative analysis of the nasal chemosensory organs of anurans during larval development and metamorphosis highlights the relative importance of chemosensory subsystems in the group.

PubMed

Jungblut, Lucas David; Reiss, John O; Paz, Dante A; Pozzi, Andrea G

2017-09-01

The anuran peripheral olfactory system is composed of a number of subsystems, represented by distinct neuroepithelia. These include the main olfactory epithelium and vomeronasal organ (found in most tetrapods) and three specialized epithelia of anurans: the buccal-exposed olfactory epithelium of larvae, and the olfactory recess and middle chamber epithelium of postmetamorphic animals. To better characterize the developmental changes in these subsystems across the life cycle, morphometric changes of the nasal chemosensory organs during larval development and metamorphosis were analyzed in three different anuran species (Rhinella arenarum, Hypsiboas pulchellus, and Xenopus laevis). We calculated the volume of the nasal chemosensory organs by measuring the neuroepithelial area from serial histological sections at four different stages. In larvae, the vomeronasal organ was relatively reduced in R. arenarum compared with the other two species; the buccal-exposed olfactory epithelium was absent in X. laevis, and best developed in H. pulchellus. In postmetamorphic animals, the olfactory epithelium (air-sensitive organ) was relatively bigger in terrestrial species (R. arenarum and H. pulchellus), whereas the vomeronasal and the middle chamber epithelia (water-sensitive organs) was best developed in X. laevis. A small olfactory recess (likely homologous with the middle chamber epithelium) was found in R. arenarum juveniles, but not in H. pulchellus. These results support the association of the vomeronasal and middle chamber epithelia with aquatic olfaction, as seen by their enhanced development in the secondarily aquatic juveniles of X. laevis. They also support a role for the larval buccal-exposed olfactory epithelium in assessment of oral contents: it was absent in X. laevis, an obligate suspension feeder, while present in the two grazing species. These initial quantitative results give, for the first time, insight into the functional importance of the peripheral olfactory subsystems across the anuran life cycle. © 2017 Wiley Periodicals, Inc.

Inactivation of the olfactory marker protein (OMP) gene in river dolphins and other odontocete cetaceans.

PubMed

Springer, Mark S; Gatesy, John

2017-04-01

Various toothed whales (Odontoceti) are unique among mammals in lacking olfactory bulbs as adults and are thought to be anosmic (lacking the olfactory sense). At the molecular level, toothed whales have high percentages of pseudogenic olfactory receptor genes, but species that have been investigated to date retain an intact copy of the olfactory marker protein gene (OMP), which is highly expressed in olfactory receptor neurons and may regulate the temporal resolution of olfactory responses. One hypothesis for the retention of intact OMP in diverse odontocete lineages is that this gene is pleiotropic with additional functions that are unrelated to olfaction. Recent expression studies provide some support for this hypothesis. Here, we report OMP sequences for representatives of all extant cetacean families and provide the first molecular evidence for inactivation of this gene in vertebrates. Specifically, OMP exhibits independent inactivating mutations in six different odontocete lineages: four river dolphin genera (Platanista, Lipotes, Pontoporia, Inia), sperm whale (Physeter), and harbor porpoise (Phocoena). These results suggest that the only essential role of OMP that is maintained by natural selection is in olfaction, although a non-olfactory role for OMP cannot be ruled out for lineages that retain an intact copy of this gene. Available genome sequences from cetaceans and close outgroups provide evidence of inactivating mutations in two additional genes (CNGA2, CNGA4), which imply further pseudogenization events in the olfactory cascade of odontocetes. Selection analyses demonstrate that evolutionary constraints on all three genes (OMP, CNGA2, CNGA4) have been greatly reduced in Odontoceti, but retain a signature of purifying selection on the stem Cetacea branch and in Mysticeti (baleen whales). This pattern is compatible with the 'echolocation-priority' hypothesis for the evolution of OMP, which posits that negative selection was maintained in the common ancestor of Cetacea and was not relaxed significantly until the evolution of echolocation in Odontoceti. Copyright © 2017 Elsevier Inc. All rights reserved.

A circadian clock in the olfactory bulb anticipates feeding during food anticipatory activity.

PubMed

Nolasco, Nahum; Juárez, Claudia; Morgado, Elvira; Meza, Enrique; Caba, Mario

2012-01-01

Rabbit pups ingest food, in this case milk, once a day with circadian periodicity and are a natural model of food anticipatory activity. During nursing, several sensory systems receive information about properties of the food, one of them being the olfactory system, which has received little attention in relation to synchronization by food. In addition, the olfactory bulb has a circadian pacemaker that exhibits rhythms independently of the suprachiasmatic nucleus, but the biological functions of these rhythms are largely unknown. In the present contribution, we hypothesized that circadian suckling of milk synchronizes rhythms in the olfactory bulb. To this aim we explored by immunohistochemistry, rhythms of FOS and PER1 proteins, as indicators of activation and reporter of oscillations, respectively, through a complete 24-h cycle in periglomerular, mitral and granular cell layers of both the main and the accessory olfactory bulb. Subjects were 7-day-old rabbit pups scheduled to nurse during the night (02:00 h) or day (10:00 h), and also fasted subjects, to explore the possible persistence of oscillations. In the three layers of the main olfactory bulb, FOS was high at time of nursing, then further increased 1.5 h afterward, and then decreased to increase again in advance of the next nursing bout. This pattern persisted, without the postprandial increase, in fasted subjects with a shift in subjects nursed at 02:00. PER1 was increased 2-8 h after nursing and this increase persisted in most cell layers, with a shift, in fasted subjects. In the accessory olfactory bulb we only observed a consistent pattern of FOS expression in the mitral cell layer of nursed subjects, similar to that of the main olfactory bulb. We conclude that the main olfactory bulb is synchronized during milk ingestion, but during fasting its oscillations perhaps are modulated by the suprachiasmatic nucleus, as proposed for rodents.

Unraveling Cajal's view of the olfactory system

PubMed Central

Figueres-Oñate, María; Gutiérrez, Yolanda; López-Mascaraque, Laura

2014-01-01

The olfactory system has a highly regular organization of interconnected synaptic circuits from the periphery. It is therefore an excellent model for understanding general principles about how the brain processes information. Cajal revealed the basic cell types and their interconnections at the end of the XIX century. Since his original descriptions, the observation and analysis of the olfactory system and its components represents a major topic in neuroscience studies, providing important insights into the neural mechanisms. In this review, we will highlight the importance of Cajal contributions and his legacy to the actual knowledge of the olfactory system. PMID:25071462

Tunicamycin impairs olfactory learning and synaptic plasticity in the olfactory bulb.

PubMed

Tong, Jia; Okutani, Fumino; Murata, Yoshihiro; Taniguchi, Mutsuo; Namba, Toshiharu; Wang, Yu-Jie; Kaba, Hideto

2017-03-06

Tunicamycin (TM) induces endoplasmic reticulum (ER) stress and inhibits N-glycosylation in cells. ER stress is associated with neuronal death in neurodegenerative disorders, such as Parkinson's disease and Alzheimer's disease, and most patients complain of the impairment of olfactory recognition. Here we examined the effects of TM on aversive olfactory learning and the underlying synaptic plasticity in the main olfactory bulb (MOB). Behavioral experiments demonstrated that the intrabulbar infusion of TM disabled aversive olfactory learning without affecting short-term memory. Histological analyses revealed that TM infusion upregulated C/EBP homologous protein (CHOP), a marker of ER stress, in the mitral and granule cell layers of MOB. Electrophysiological data indicated that TM inhibited tetanus-induced long-term potentiation (LTP) at the dendrodendritic excitatory synapse from mitral to granule cells. A low dose of TM (250nM) abolished the late phase of LTP, and a high dose (1μM) inhibited the early and late phases of LTP. Further, high-dose, but not low-dose, TM reduced the paired-pulse facilitation ratio, suggesting that the inhibitory effects of TM on LTP are partially mediated through the presynaptic machinery. Thus, our results support the hypothesis that TM-induced ER stress impairs olfactory learning by inhibiting synaptic plasticity via presynaptic and postsynaptic mechanisms in MOB. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Activity-dependent expression of miR-132 regulates immediate-early gene induction during olfactory learning in the greater short-nosed fruit bat, Cynopterus sphinx.

PubMed

Mukilan, Murugan; Ragu Varman, Durairaj; Sudhakar, Sivasubramaniam; Rajan, Koilmani Emmanuvel

2015-04-01

The activity-dependent expression of immediate-early genes (IEGs) and microRNA (miR)-132 has been implicated in synaptic plasticity and the formation of long-term memory (LTM). In the present study, we show that olfactory training induces the expression of IEGs (EGR-1, C-fos, C-jun) and miR-132 at similar time scale in olfactory bulb (OB) of Cynopterus sphinx. We examined the role of miR-132 in the OB using antisense oligodeoxynucleotide (AS-ODN) and demonstrated that a local infusion of AS-ODN in the OB 2h prior to training impaired olfactory memory formation in C. sphinx. However, the infusion of AS-ODN post-training did not cause a deficit in memory formation. Furthermore, the inhibition of miR-132 reduced the olfactory training-induced expression of IEGs and post synaptic density protein-95 (PSD-95) in the OB. Additionally, we show that miR-132 regulates the activation of calcium/calmodulin-dependent protein kinase-II (CaMKII) and cAMP response element binding protein (CREB), possibly through miR-148a. These data suggest that olfactory training induces the expression of miR-132 and IEGs, which in turn activates post-synaptic proteins that regulate olfactory memory formation. Copyright © 2015 Elsevier Inc. All rights reserved.

Evolution of olfaction in non-avian theropod dinosaurs and birds

PubMed Central

Zelenitsky, Darla K.; Therrien, François; Ridgely, Ryan C.; McGee, Amanda R.; Witmer, Lawrence M.

2011-01-01

Little is known about the olfactory capabilities of extinct basal (non-neornithine) birds or the evolutionary changes in olfaction that occurred from non-avian theropods through modern birds. Although modern birds are known to have diverse olfactory capabilities, olfaction is generally considered to have declined during avian evolution as visual and vestibular sensory enhancements occurred in association with flight. To test the hypothesis that olfaction diminished through avian evolution, we assessed relative olfactory bulb size, here used as a neuroanatomical proxy for olfactory capabilities, in 157 species of non-avian theropods, fossil birds and living birds. We show that relative olfactory bulb size increased during non-avian maniraptoriform evolution, remained stable across the non-avian theropod/bird transition, and increased during basal bird and early neornithine evolution. From early neornithines through a major part of neornithine evolution, the relative size of the olfactory bulbs remained stable before decreasing in derived neoavian clades. Our results show that, rather than decreasing, the importance of olfaction actually increased during early bird evolution, representing a previously unrecognized sensory enhancement. The relatively larger olfactory bulbs of earliest neornithines, compared with those of basal birds, may have endowed neornithines with improved olfaction for more effective foraging or navigation skills, which in turn may have been a factor allowing them to survive the end-Cretaceous mass extinction. PMID:21490022

Effects of isotretinoin on the olfactory function in patients with acne*

PubMed Central

Kartal, Demet; Yaşar, Mehmet; Kartal, Levent; Özcan, Ibrahim; Borlu, Murat

2017-01-01

Background Isotretinoin is a synthetic analog of vitamin A. Recent studies support a role for retinoic acid in the recovery of olfactory function following injury in mice. Objective This study aimed at determining the effect of isotretinoin on olfactory function in patients who have acne and are otherwise healthy. Methods Forty-five patients (aged 25-40 years) with acne were included in the study. All patients underwent a rhinological examination. Olfactory function was assessed by the Sniffin' Sticks Test. The test was assessed at baseline and in the third month of isotretinoin treatment. Results Isotretinoin improved the performance of patients in the olfactory test. The SST score increased from 8.7±1.09 to 9.5±1.19 (p<0.001), prevalence of hyposmia decreased from 40% to 24% and normosmia increased from 60% to 75% (p=0.059). The percentage of patients whose olfactory function was categorized as "good" increased from 6% to 21.3%. This increase was statistically significant (p<0.05). Study limitations Absence of a control group is one of the limitations of this study. Also, we did not evaluate patients with smell test after stopping isotretinoin treatment. Conclusion We examined the effect of systemic isotretinoin on olfactory function. It can be concluded from the present investigation that isotretinoin therapy improves the sense of smell. PMID:28538877

Evaluation of olfactory and auditory system effects of the antihyperthyroid drug carbimazole in the Long-Evans rat.

PubMed

Genter, M B

1998-01-01

Carbimazole (2-carbethoxythio-1-methylimidazole) is a thiocarbamide drug used in the treatment of hyperthyroidism in humans. Side effects associated with carbimazole treatment are reported to include impaired taste, impaired olfaction, and hearing loss. The structurally similar antihyperthyroid drug methimazole (1-methyl-2-mercaptoimidazole), also reportedly associated with impaired taste and olfaction in humans, has recently been demonstrated by this laboratory to be an olfactory toxicant by both the oral and intraperitoneal routes of exposure in rodents. A systematic evaluation of sensory system effects of these compounds, either in rodents or humans, is not available in the literature. Male Long-Evans rats were used to evaluate the auditory and olfactory toxicity of carbimazole by two routes of exposure. Histopathological evaluation of nasal cavities from rats administered carbimazole via i.p. and oral routes revealed olfactory mucosal damage and early evidence of repair; a no-observed effect level (NOEL) of 100 mg/kg was observed for orally administered carbimazole. Further, these studies demonstrate evidence for the generation of the olfactory toxic metabolites of carbimazole by the olfactory mucosa itself, as incubation of carbimazole with an olfactory S9 preparation resulted in NADPH-dependent degradation of carbimazole. Evaluation of the auditory startle response in carbimazole-treated rats revealed no deficits, demonstrating that carbimazole does not cause a global loss of hearing in rats.

Numerical Comparison of Nasal Aerosol Administration Systems for Efficient Nose-to-Brain Drug Delivery.

PubMed

Dong, Jingliang; Shang, Yidan; Inthavong, Kiao; Chan, Hak-Kim; Tu, Jiyuan

2017-12-29

Nose-to-brain drug administration along the olfactory and trigeminal nerve pathways offers an alternative route for the treatment of central nervous system (CNS) disorders. The characterization of particle deposition remains difficult to achieve in experiments. Alternative numerical approach is applied to identify suitable aerosol particle size with maximized inhaled doses. This study numerically compared the drug delivery efficiency in a realistic human nasal cavity between two aerosol drug administration systems targeting the olfactory region: the aerosol mask system and the breath-powered bi-directional system. Steady inhalation and exhalation flow rates were applied to both delivery systems. The discrete phase particle tracking method was employed to capture the aerosol drug transport and deposition behaviours in the nasal cavity. Both overall and regional deposition characteristics were analysed in detail. The results demonstrated the breath-powered drug delivery approach can produce superior olfactory deposition with peaking olfactory deposition fractions for diffusive 1 nm particles and inertial 10 μm. While for particles in the range of 10 nm to 2 μm, no significant olfactory deposition can be found, indicating the therapeutic agents should avoid this size range when targeting the olfactory deposition. The breath-powered bi-directional aerosol delivery approach shows better drug delivery performance globally and locally, and improved drug administration doses can be achieved in targeted olfactory region.

Olfactory Context-Dependent Memory and the Effects of Affective Congruency.

PubMed

Hackländer, Ryan P M; Bermeitinger, Christina

2017-10-31

Odors have been claimed to be particularly effective mnemonic cues, possibly because of the strong links between olfaction and emotion processing. Indeed, past research has shown that odors can bias processing towards affectively congruent material. In order to determine whether this processing bias translates to memory, we conducted 2 olfactory-enhanced-context memory experiments where we manipulated affective congruency between the olfactory context and to-be-remembered material. Given the presumed importance of valence to olfactory perception, we hypothesized that memory would be best for affectively congruent material in the olfactory enhanced context groups. Across the 2 experiments, groups which encoded and retrieved material in the presence of an odorant exhibited better memory performance than groups that did not have the added olfactory context during encoding and retrieval. While context-enhanced memory was exhibited in the presence of both pleasant and unpleasant odors, there was no indication that memory was dependent on affective congruency between the olfactory context and the to-be-remembered material. While the results provide further support for the notion that odors can act as powerful contextual mnemonic cues, they call into question the notion that affective congruency between context and focal material is important for later memory performance. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Morphogenetic Studies of the Drosophila DA1 Ventral Olfactory Projection Neuron

PubMed Central

Yu, Hung-Hsiang

2016-01-01

In the Drosophila olfactory system, odorant information is sensed by olfactory sensory neurons and relayed from the primary olfactory center, the antennal lobe (AL), to higher olfactory centers via olfactory projection neurons (PNs). A major portion of the AL is constituted with dendrites of four groups of PNs, anterodorsal PNs (adPNs), lateral PNs (lPNs), lateroventral PNs (lvPNs) and ventral PNs (vPNs). Previous studies have been focused on the development and function of adPNs and lPNs, while the investigation on those of lvPNs and vPNs received less attention. Here, we study the molecular and cellular mechanisms underlying the morphogenesis of a putative male-pheromone responding vPN, the DA1 vPN. Using an intersection strategy to remove background neurons labeled within a DA1 vPN-containing GAL4 line, we depicted morphological changes of the DA1 vPN that occurs at the pupal stage. We then conducted a pilot screen using RNA interference knock-down approach to identify cell surface molecules, including Down syndrome cell adhesion molecule 1 and Semaphorin-1a, that might play essential roles for the DA1 vPN morphogenesis. Taken together, by revealing molecular and cellular basis of the DA1 vPN morphogenesis, we should provide insights into future comprehension of how vPNs are assembled into the olfactory neural circuitry. PMID:27163287

Morphogenetic Studies of the Drosophila DA1 Ventral Olfactory Projection Neuron.

PubMed

Shen, Hung-Chang; Wei, Jia-Yi; Chu, Sao-Yu; Chung, Pei-Chi; Hsu, Tsai-Chi; Yu, Hung-Hsiang

2016-01-01

In the Drosophila olfactory system, odorant information is sensed by olfactory sensory neurons and relayed from the primary olfactory center, the antennal lobe (AL), to higher olfactory centers via olfactory projection neurons (PNs). A major portion of the AL is constituted with dendrites of four groups of PNs, anterodorsal PNs (adPNs), lateral PNs (lPNs), lateroventral PNs (lvPNs) and ventral PNs (vPNs). Previous studies have been focused on the development and function of adPNs and lPNs, while the investigation on those of lvPNs and vPNs received less attention. Here, we study the molecular and cellular mechanisms underlying the morphogenesis of a putative male-pheromone responding vPN, the DA1 vPN. Using an intersection strategy to remove background neurons labeled within a DA1 vPN-containing GAL4 line, we depicted morphological changes of the DA1 vPN that occurs at the pupal stage. We then conducted a pilot screen using RNA interference knock-down approach to identify cell surface molecules, including Down syndrome cell adhesion molecule 1 and Semaphorin-1a, that might play essential roles for the DA1 vPN morphogenesis. Taken together, by revealing molecular and cellular basis of the DA1 vPN morphogenesis, we should provide insights into future comprehension of how vPNs are assembled into the olfactory neural circuitry.

Illuminating odors: when optogenetics brings to light unexpected olfactory abilities

PubMed Central

Grimaud, Julien

2016-01-01

For hundreds of years, the sense of smell has generated great interest in the world literature, oenologists, and perfume makers but less of scientists. Only recently this sensory modality has gained new attraction in neuroscience when original tools issued from physiology, anatomy, or molecular biology were available to decipher how the brain makes sense of olfactory cues. However, this move was promptly dampened by the difficulties of developing quantitative approaches to study the relationship between the physical characteristics of stimuli and the sensations they create. An upswing of olfactory investigations occurred when genetic tools could be used in combination with devices borrowed from the physics of light (a hybrid technique called optogenetics) to scrutinize the olfactory system and to provide greater physiological precision for studying olfactory-driven behaviors. This review aims to present the most recent studies that have used light to activate components of the olfactory pathway, such as olfactory receptor neurons, or neurons located further downstream, while leaving intact others brain circuits. With the use of optogenetics to unravel the mystery of olfaction, scientists have begun to disentangle how the brain makes sense of smells. In this review, we shall discuss how the brain recognizes odors, how it memorizes them, and how animals make decisions based on odorants they are capable of sensing. Although this review deals with olfaction, the role of light will be central throughout. PMID:27194792

Matching- and Nonmatching-to-Sample Concept Learning in Rats Using Olfactory Stimuli

ERIC Educational Resources Information Center

April, L. Brooke; Bruce, Katherine; Galizio, Mark

2011-01-01

Previous research has shown that rats can learn matching-to-sample relations with olfactory stimuli; however, the specific characteristics of this relational control are unclear. In Experiment 1, 6 rats were trained to either match or nonmatch to sample in a modified operant chamber using common household spices as olfactory stimuli. After…

Odor-Specific Habituation Arises from Interaction of Afferent Synaptic Adaptation and Intrinsic Synaptic Potentiation in Olfactory Cortex

ERIC Educational Resources Information Center

Linster, Christiane; Menon, Alka V.; Singh, Christopher Y.; Wilson, Donald A.

2009-01-01

Segmentation of target odorants from background odorants is a fundamental computational requirement for the olfactory system and is thought to be behaviorally mediated by olfactory habituation memory. Data from our laboratory have shown that odor-specific adaptation in piriform neurons, mediated at least partially by synaptic adaptation between…