Olfactory Capacity Research Articles

Middle Turbinate Evacuation Conchoplasty in Management of Contact-Point Rhinogenic Headache in Children

Background: Our objective is to evaluate the efficacy and outcomes of endoscopic evacuation of middle turbinate "concha bullosa" compared with lateral partial turbinectomy, in children with chronic contact-point headaches. For the research, this study is using prospective clinical trial and setting in Otolaryngology department, Tanta University Hospital, Egypt. Methods: Over three years, 60 children underwent surgery for management of contact-point rhinogenic chronic headache resulting from middle turbinate concha bullosa, using either an evacuation technique (30 children) or lateral partial turbinectomy (lamellectomy technique, 30 children) with at least 12 months' follow up. Post-operative adhesions, olfactory disorders, pain intensity, and frequency and duration of headache attacks were monitored. Results: None of the children of the evacuation group developed post-operative synechia or olfactory disorders. In the lamellectomy group, two children reported reduced olfactory capacity and an additional four children had developed adhesions. Pain intensity and frequency and duration of headache attacks improved significantly in both groups (pre- vs post-operative results), but significantly more so in the evacuation group. Conclusion: The evacuation technique may be superior to the lamellectomy technique in preventing post-operative synechia and olfactory disorders, as well as better relieving of pain intensity and frequency and duration of headache attacks. doi: http://dx.doi.org/10.4021/ijcp53w

Why humans do not make good vampires. Testing the ability of humans to detect true blood

Background: Research indicating the effects of real blood or of its iconic representation on human behaviour has thus far concentrated on phobia and aggressiveness. Little is known about other responses or, more fundamentally, about the biological basis of all such responses.Aim: In this study it is examined whether or not humans are able to detect real blood.Methods: Human subjects (n = 89) were asked to distinguish different kinds of blood from red control fluids under varying visual and choice conditions. Relevant differences between subjects were tested for through written questionnaires, including standardized scales for disgust sensitivity (DS-R) and blood phobia (MBPI) and performance on two clinical olfactory tests.Results: Analysis of variance shows that humans are excellent detectors of animal blood (in casu pig blood), whereas the ability of detecting human blood is much less developed. Surprisingly, differences in olfactory capacities and personal experience with blood have no effect on blood detection, while blood fear lowers and disgust sensitivity ameliorates this performance.Conclusion: This study allows further mapping of the exact role of disgust sensitivity in human behaviour, as well as a deliberate choice of materials in blood-related experiments. It is imperative for further research on the behavioural and psychological impact ‘blood’ resorts on humans.

Absence of colony stimulation factor-1 receptor results in loss of microglia, disrupted brain development and olfactory deficits.

The brain contains numerous mononuclear phagocytes called microglia. These cells express the transmembrane tyrosine kinase receptor for the macrophage growth factor colony stimulating factor-1 (CSF-1R). Using a CSF-1R-GFP reporter mouse strain combined with lineage defining antibody staining we show in the postnatal mouse brain that CSF-1R is expressed only in microglia and not neurons, astrocytes or glial cells. To study CSF-1R function we used mice homozygous for a null mutation in the Csflr gene. In these mice microglia are >99% depleted at embryonic day 16 and day 1 post-partum brain. At three weeks of age this microglial depletion continues in most regions of the brain although some contain clusters of rounded microglia. Despite the loss of microglia, embryonic brain development appears normal but during the post-natal period the brain architecture becomes perturbed with enlarged ventricles and regionally compressed parenchyma, phenotypes most prominent in the olfactory bulb and cortex. In the cortex there is increased neuronal density, elevated numbers of astrocytes but reduced numbers of oligodendrocytes. Csf1r nulls rarely survive to adulthood and therefore to study the role of CSF-1R in olfaction we used the viable null mutants in the Csf1 (Csf1op) gene that encodes one of the two known CSF-1R ligands. Food-finding experiments indicate that olfactory capacity is significantly impaired in the absence of CSF-1. CSF-1R is therefore required for the development of microglia, for a fully functional olfactory system and the maintenance of normal brain structure.

Rehabilitación olfativa tras la laringectomía total

ObjectivesTo analyze the olfactory function in patients after total laryngectomy and evaluate the outcomes of the use of the induced nasal airflow manoeuvre. Material and methodsA prospective clinical intervention study was carried out with 41 patients who had undergone total laryngectomy, of which 39 were male and 2 female. After verifying that there were no anatomical disorders, the patients were given an olfaction test that classified them into two groups, those with olfactory perception and those without. All underwent rehabilitation using the induced nasal airflow technique and, subsequently, the olfaction test was repeated to enable a comparison with the first results obtained. A semi-structured interview was held to evaluate the senses of taste and smell of the participants, also taking into account their own opinion. ResultsOut of the 41 patients included in the study, 9 had olfactory perception before rehabilitation, according to the first olfaction test. The use of the nasal airflow maneuver meant the recovery or improvement of the olfactory capacity in 90.24% of the patients. ConclusionsThe induced nasal airflow technique enables an important recovery of olfaction and improvement of taste after total laryngectomy. This technique is easy to learn and to repeat. It does not require expensive materials. The recovery of olfaction and taste implies an improvement in quality of life for the patient, so this technique should be included in all protocols of comprehensive rehabilitation after total laryngectomy.

Expression and distribution of the intermediate filament protein nestin and other stem cell related molecules in the human olfactory epithelium.

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.

Subtype-selective nicotinic agonists enhance olfactory working memory in normal rats: A novel use of the odour span task

Nicotinic agonists have been shown to enhance performance in cognitive tasks based on attention and memory. The aim of this study was to use a test of olfactory working memory; the odour span task (OST) in rodents, to investigate the effects of subtype-specific nicotinic agonists on working memory in normal rats. Rats were trained in a non-matching to sample (NMTS) rule and then the full OST, which involved identifying a novel odour from an increasing number of presented odours. Male hooded Lister rats were treated with nicotine, selective nicotinic agonists or vehicle (saline). In order to validate the task, muscarinic and nicotinic receptor antagonists were also examined. Nicotine at both 0.05 and 0.1mg/kg significantly increased mean span length in the OST. The selective alpha 4 beta 2 nicotinic receptor agonist metanicotine (0.1mg/kg s.c.) and the selective alpha 7 nicotinic receptor agonist (R)-N-(1-azabicyclo[2.2.2]oct-3-yl)(5-(2-pyridyl)thiophene-2-carboxamide) (compound A, 10mg/kg i.p.) also improved performance. In contrast, mecamylamine and scopolamine significantly decreased mean span length. These findings suggest a role for the activation of both alpha 4 beta 2 and alpha 7 subtypes of neuronal nicotinic receptor in mediating enhancements of olfactory working memory capacity in normal, non-compromised rats. These nicotinic receptor subtypes may therefore prove to be useful targets for the development of novel treatments for neuropsychiatric disorders that involve cognitive dysfunction.

How does long-term odor deprivation affect the olfactory capacity of adult mice?

BackgroundUnilateral naris occlusion (UNO) has been the most common method of effecting stimulus deprivation in studies of olfactory plasticity. However, despite the large corpus on the effects of this manipulation, dating back to the 19th century, little is known about its behavioral sequela. Here we report the results of standard olfactory habituation and discrimination studies on adult mice that had undergone perinatal UNO followed by adult contralateral olfactory bulbectomy (bulb-x).MethodsThe olfactory performance of UNO mice was compared to matched controls that had unilateral bulb-x but open nares. Both habituation and discrimination (operant) experiments employed a protocol in which after successful dishabituation or discrimination to dilute individual odors (A = 0.01% isoamyl acetate; B = 0.01% ethyl butyrate; each v/v in mineral oil), mice were challenged with a single odor versus a mixture comparison (A vs. A + B). In a series of tests the volume portion of Odor B in the mixture was systematically decreased until dishabituation or discrimination thresholds were reached.ResultsFor the habituation experiment, UNOs (n = 10) and controls (n = 9) dishabituated to a 10% mixture of Odor B in Odor A after being habituated to A alone, while both groups failed to show differential responding to a 2% mixture of B in A. However, the UNO group's increased investigation durations for the 2% mixture approached significance (p < 0.06). A replication of this study (7 controls & 8 UNOs) confirmed that controls did not differentiate Odor A and a 2% mixture of B in A but UNOs did not (p < 0.05). For the discrimination experiment, 4 UNOs and 4 controls were shaped to dig in one of two containers of sand that contained the S+ odor (Odor B) to obtain sugar pellet rewards. As in the habituation experiment, UNOs displayed greater olfactory capacity than controls on this task. Controls and UNOs had an average mixture discrimination threshold of 1.6% (± 0.4) and 0.22% (± 0.102) respectively, a difference that was statistically significant (p < 0.02).ConclusionsAdult mice relying on an olfactory system deprived of odor by naris occlusion from near the time of birth display enhanced olfactory capacity compared to control mice. This counterintuitive result suggests that UNO is neither an absolute method of deprivation nor does it diminish olfactory capabilities. Enhanced olfactory capacity, as observed in the current study, that is a consequence of deprivation, is consistent with recent molecular and physiological evidence that stimulus deprivation triggers compensatory processes throughout the olfactory system.

Olfactory rehabilitation after total laringectomy

ObjectivesTo analyse the olfactory function in patients after total laryngectomy and evaluate the outcomes of using the nasal airflow-inducing manoeuvre. Material and methodsA prospective clinical intervention study was carried out with 41 patients who had undergone total laryngectomy, of which 39 were male and 2 female. After verifying that there were no anatomical disorders, the patients were given an olfaction test that classified them into two groups, those with olfactory perception and those without. All underwent rehabilitation using the induced nasal airflow technique and, subsequently, the olfaction test was repeated to enable a comparison with the first results obtained. A semi-structured interview was held to evaluate the senses of taste and smell of the participants, also taking into account their own opinion. ResultsOut of the 41 patients included in the study, 9 had olfactory perception before rehabilitation, according to the first olfaction test. The use of the nasal airflow manoeuvre meant the recovery or improvement of the olfactory capacity in 90.24% of the patients. ConclusionsThe nasal airflow-inducing technique enables an important recovery of olfaction and improvement of taste after total laryngectomy. This technique is easy to learn and to repeat. It does not require expensive materials. The recovery of olfaction and taste implies an improvement in quality of life for the patient, so this technique should be included in all protocols of comprehensive rehabilitation after total laryngectomy.

The Olfactory Pathway of Adult and Larval Drosophila

Tracing of olfactory projections based on odorant receptor expression has led to an almost complete receptor-to-glomerulus map in adult Drosophila. While most of the glomeruli may be involved in processing of food odors, others appear to be more specialized, for example, responding to CO(2) or to pheromonal cues. Recent studies have shed light on signal processing in the antennal lobe and in higher centers. Newly detected cholinergic excitatory local interneurons in the antennal lobe appear to provide substrates for the broad odor tuning properties of projection neurons. In the mushroom bodies, projection neurons establish an intricate divergence-convergence network with their target cells, allowing complex modes of signal transfer. In the lateral horn, projection neurons innervating candidate pheromone glomeruli appear to segregate from those innervating "normal" glomeruli. Hence, pheromone and food information may be handled by separate channels, consistent with discrete behavioral meanings of the two kinds of signals. The olfactory pathway of the larva shares the general layout of its adult counterpart, with a number of simplifications. The presence of only 21 glomeruli suggests a reduction of primary olfactory "dimensions" compared to adults. The existence of a pheromone-sensing subsystem is unlikely. Larval glomeruli are targets of single, unique sensory neurons rather than being sites of convergence as in the adult. Projection neuron outputs are restricted to single glomeruli in the mushroom body. Their target cells either innervate one or several of them creating substrates for elementary odor coding and coincidence detection. In conclusion, olfactory discrimination capacities of the larva are very likely reduced, consistent with the requirements of a substrate feeder.

The Dark Side of “The Nose”: The Paradigms of Olfactory Perception in Gogol'’s “The Nose”

The article focuses on the ways in which Nikolai Gogol'’s famous story “The Nose” can be viewed meaningfully after being designated as the token of nonsense and illogicality by representatives of structuralism and hermeneutics in Slavic studies. Instead of interpreting the story’s symbolic significance or establishing its connections to other texts, the present article examines the story literally and asks what it means to lose one’s olfactory capacity in the Russian capital in the first third of the nineteenth century. The article’s answer is that Gogol'’s story can be seen as marking the moment during which the traditional olfactory-rich values of Russian culture gave way to a more vision-oriented Western sensory paradigm that tended to denigrate the sense of smell and its cognitive potential.

Olfactory Dysfunction is Associated with Subjective Memory Complaints in Community-Dwelling Elderly Individuals

Olfactory dysfunction has been reported in clinical and preclinical phases of Alzheimer's disease. Subjective memory complaints have been proposed as a potential early indicator for increased risk of Alzheimer's disease, but have also been associated with depression, personality characteristics, and health problems. In this study, we aimed to determine which of these putative markers can predict memory complaints in community-dwelling elderly individuals, focusing on olfactory symptoms. A cohort of 144 elderly volunteers (42 males and 102 females), aged 50 to 86, was recruited from an ongoing longitudinal study. Participants were assessed for olfactory capacities (threshold, discrimination, and identification), subjective memory complaints, depression, and cognitive functions. Subjective memory complaints were significantly associated with olfactory discrimination and identification but not with threshold. Olfactory functions and depressive symptoms were both significantly associated with subjective memory complaints. In addition, memory complainers were significantly worse than non-complainers with respect to olfactory discrimination, identification, and overall olfactory functioning. The findings suggest that olfactory capacity may be a potentially significant biomarker for identifying community-dwelling elderly with memory complaints who are at increased risk for age-related cognitive decline and Alzheimer's disease.

Identification of Nonepithelial Multipotent Cells in the Embryonic Olfactory Mucosa

Olfactory mucosal (OM) tissue, a potential source of stem cells, is currently being assessed in the clinic as a candidate tissue for transplant-mediated repair of spinal cord injury. We examined the ability of embryonic rat OM tissue to generate stem cells using culture conditions known to promote neural stem cell proliferation. Primary spheres formed that proliferated and exhibited two main morphologies: (a) CNS neurosphere-like (OM-I) and (b) small, tight spheroid-like (OM-II). The OM-I spheres expressed the neural stem cell marker nestin but also markers of peripheral glia, neurons, and connective tissue. Further studies demonstrated the presence of multipotential mesenchymal-like stem cells within OM-I spheres that differentiated into bone, adipose, and smooth muscle cells. In contrast, the OM-II spheres contained mainly cytokeratin-expressing cells. Immunolabeling of rat olfactory tissue with Stro-1, CD90, and CD105 showed the presence of multipotent mesenchymal cells in the lamina propria, whereas cytokeratin was expressed by the epithelial cells of the olfactory epithelium. In addition, a comparable pattern of immunoreactivity was detected in human tissue using Stro-1 and cytokeratin, suggesting the presence of similar cells in this tissue. The identification of a nonepithelial multipotent cell in the OM may explain the varied reports on olfactory stem cell differentiation capacity in vitro and in vivo and illustrates the cellular complexity of this tissue as a potential source of stem cells for transplantation and translation to the clinic.

Decreased olfactory mucus secretion and nasal abnormality in mice lacking type 2 and type 3 IP3 receptors

Although nasal mucus is thought to play important roles in the mammalian olfactory system, the mechanisms of secretion of it and its physiological roles are poorly understood. Here we show that type 2 and type 3 IP3 receptors (IP3R2 and IP3R3) play critical roles in olfactory mucus secretion. Histological studies showed that IP3R2 and IP3R3 are predominantly expressed in two types of nasal glands, the anterior glands of the nasal septum and the lateral nasal glands (LNG), which contain mucosal proteins secreted to the main olfactory epithelium. We therefore examined LNG acinar cells, and found that acetylcholine-mediated calcium responses and fluid- and protein- secretion in the acinar cells were markedly decreased in IP3R2-R3 double-knockout (KO) mice. We also found nasal inflammation and a decrease in olfactory capacity in IP3R2-R3 KO mice. Despite intact signal transduction in the olfactory epithelium, IP3R2-R3 KO mice exhibited elevated threshold sensitivity to odorants on in vivo imaging of olfactory glomerular responses and behavioral tests. Our findings suggest that IP3R2 and IP3R3 mediate nasal mucus secretion, which is important for the maintenance of nasal tissue as well as the perception of odors.

Chemosensory Deprivation in Juvenile Coho Salmon Exposed to Dissolved Copper under Varying Water Chemistry Conditions

Dissolved copper is an important nonpoint source pollutant in aquatic ecosystems worldwide. Copper is neurotoxic to fish and is specifically known to interfere with the normal function of the peripheral olfactory nervous system. However,the influence of water chemistry on the bioavailability and toxicity of copper to olfactory sensory neurons is not well understood. Here we used electrophysiological recordings from the olfactory epithelium of juvenile coho salmon (Oncorhynchus kisutch) to investigate the impacts of copper in freshwaters with different chemical properties. In low ionic strength artificial fresh water, a short-term (30 min) exposure to 20 microg/L dissolved copper reduced the olfactory response to a natural odorant (10(-5) M L-serine) by 82%. Increasing water hardness (0.2-1.6 mM Ca) or alkalinity (0.2-3.2 mM HCO3-) only slightly diminished the inhibitory effects of copper. Moreover, the loss of olfactory function was not affected by a change in pH from 8.6 to 7.6. By contrast, olfactory capacity was partially restored by increasing dissolved organic carbon (DOC; 0.1-6.0 mg/L). Given the range of natural water quality conditions in the western United States, water hardness and alkalinity are unlikelyto protect threatened or endangered salmon from the sensory neurotoxicity of copper. However, the olfactory toxicity of copper may be partially reduced in surface waters that have a high DOC content.

Lipid nutrition and settlement behaviour in American lobster Homarus americanus

This study examines the effects of varying dietary lipids on growth, survival, lipid com- position and behaviour in lobster Homarus americanus (Milne Edwards, 1837) postlarvae. Lobsters were fed one of 3 diets during their early ontogeny: (1) Artemac, a widely used Artemia replacement; (2) a ternary mixture consisting of Artemac, frozen Artemia adults and Artemia flakes; or (3) a mix- ture of live A. salina nauplii and adults. We evaluated the olfactory capacity (response to predator odour plume) and cryptic behaviour (ability to hide during settlement) of lobster postlarvae as a function of these diets and the lipid and the fatty acid composition of lobsters. Growth and survival of lobster postlarvae were highest in those fed live Artemia, followed by the ternary mix, then Artemac. The low performance of lobster postlarvae fed Artemac may be attributable to dietary deficiencies in phospholipids (PLs) or 20:4n-6 and coincided with low levels of endogenous triacylglycerols (TAG). Those lobsters fed live Artemia showed low levels of 22:6n-3 and 20:5n-3 compared to levels occur- ring in wild animals. Here we report the selective incorporation of 20:4n-6, 20:5n-3 and 22:6n-3 to polar lipids and, to a lesser extent, to neutral lipids in lobsters. Finally, lobster postlarvae fed the 3 experimental diets responded to a predator odour plume by reducing their activity levels and increas- ing the time spent swimming downstream. However, lobster settlement behaviour varied as a func- tion of the diet: low-performing lobsters fed Artemac were less active than those fed the other diets, presumably due to low levels of endogenous TAG or changes in dietary long-chain PUFA.

Effectiveness of Olfactory Rehabilitation With the Nasal Airflow-Inducing Maneuver After Total Laryngectomy

To assess the long-term results of the nasal airflow-inducing maneuver in olfaction rehabilitation in patients who had undergone laryngectomy. Prospective interventional study. University hospital. Twenty-four patients who had undergone laryngectomy (21 men and 3 women; mean age, 68 years) who received olfactory rehabilitation with the nasal airflow-inducing maneuver were reevaluated 6 and 12 months after primary treatment. Olfactory function was tested by means of a semistructured interview; the Questionnaire on Olfaction, Taste and Appetite; and the Scandinavian Odor-Identification Test. Quality of life was measured with the European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-H&N35 questionnaires. Patients were categorized as smellers or nonsmellers based on results of the Scandinavian Odor-Identification Test. Before treatment, 10 of 24 patients (42%) were smellers and 14 (58%) were nonsmellers. At 6-month follow-up, 20 of 23 patients (87%) were smellers, whereas after 12 months, 21 of 24 patients (88%) were smellers. Long-term olfaction rehabilitation was achieved in 11 of 14 patients (79%) with anosmia, and 15 of all 24 patients (63%) could be classified as having normal olfactory capacity at the end of the study. The nasal airflow-inducing maneuver is a patient-friendly, inexpensive, and effective method for restoring the sense of smell in patients after laryngectomy, and the results persist in the long term.

Enhanced urinary odor discrimination in female aromatase knockout (ArKO) mice

We asked whether odor discrimination abilities are sexually dimorphic in mice and, if so, whether the perinatal actions of estradiol contribute to these sex differences. The ability to discriminate different types of urinary odors was compared in male and female wild-type (WT) subjects and in mice with a homozygous-null mutation of the estrogen synthetic enzyme, aromatase (aromatase knockout; ArKO). Olfactory discrimination was assessed in WT and ArKO male and female mice after they were gonadectomized in adulthood and subsequently treated with estradiol benzoate. A liquid olfactometer was used to assess food-motivated olfactory discrimination capacity. All animals eventually learned to distinguish between urinary odors collected from gonadally intact males and estrous females; however, WT males as well as ArKO mice of both sexes learned this discrimination significantly more rapidly than WT females. Similar group differences were obtained when mice discriminated between urinary odors collected from gonadally intact vs. castrated males or between two non-social odorants, amyl and butyl acetate. When subjects had to discriminate volatile urinary odors from ovariectomized female mice treated with estradiol sequenced with progesterone versus estradiol alone, ArKO females quickly acquired the task whereas WT males and females as well as ArKO males failed to do so. These results demonstrated a strong sex dimorphism in olfactory discrimination ability, with WT males performing better than females. Furthermore, female ArKO mice showed an enhanced ability to discriminate very similar urinary odorants, perhaps due to an increased sensitivity of the main olfactory nervous system to adult estradiol treatment as a result of perinatal estrogen deprivation.

Anatomical Contributions to Odorant Sampling and Representation in Rodents: Zoning in on Sniffing Behavior

Odorant sampling behaviors such as sniffing bring odorant molecules into contact with olfactory receptor neurons (ORNs) to initiate the sensory mechanisms of olfaction. In rodents, inspiratory airflow through the nose is structured and laminar; consequently, the spatial distribution of adsorbed odorant molecules during inspiration is predictable. Physicochemical properties such as water solubility and volatility, collectively called sorptiveness, interact with behaviorally regulable variables such as inspiratory flow rate to determine the pattern of odorant deposition along the inspiratory path. Populations of ORNs expressing the same odorant receptor are distributed in strictly delimited regions along this inspiratory path, enabling different deposition patterns of the same odorant to evoke different patterns of neuronal activation across the olfactory epithelium and in the olfactory bulb. We propose that both odorant sorptive properties and the regulation of sniffing behavior may contribute to rodents' olfactory capacities by this mechanism. In particular, we suggest that the motor regulation of sniffing behavior is substantially utilized for purposes of "zonation" or the direction of odorant molecules to defined intranasal regions and hence toward distinct populations of receptor neurons, pursuant to animals' sensory goals.

Olfactory conditioning experiments in a food-searching passerine bird in semi-natural conditions

Because passerine birds have a very small relative olfactory bulb size, they have been considered to have weak olfactory capacities for decades. Recent investigations however suggest that breeding female blue tits (Parus caeruleus) are sensitive to lavender odour in the reproductive context of building and maintaining the nest. Here, we present results of an olfactory conditioning experiment in blue tits held in semi-natural conditions during the breeding season. We show that captive male blue tits, trained to associate lavender odour with a food reward, are more attracted to an empty feeder box emitting lavender odour than an odourless empty feeder box. Females did not distinguish significantly between empty feeders with and without lavender odour during the test phase, although they responded positively at the end of the training phase. These results suggest that male blue tits can use olfaction in a context not related to nest building. Additional experiments will be required to better understand the observed sex differences in response to the experimental set up, and in what context free-ranging individuals use olfaction.

Olfactory Evaluation in Children: Application to the CHARGE Syndrome

To find an efficient tool for testing olfactory function in children and use it to investigate a group of children with CHARGE (coloboma, congenital heart disease, choanal atresia, mental and growth retardation, genital anomalies, and ear malformations and hearing loss) syndrome. We adapted for children an olfaction test that had just been validated in an adult French population and investigated a control group of 25 healthy children aged 6 to 13 years. We then tested the olfactory capacity of a group of 14 children with CHARGE syndrome, aged 6 to 18 years. A questionnaire was completed with the parents about their children's feeding difficulties and their ability to recognize odors in everyday life. We recorded and scored the histories of feeding behavior anomalies, the visual and auditory status, and current intellectual levels. MRI of the olfactory tracts and bulbs was analyzed for 9 of 14 children. We showed that healthy children have similar olfactory function to that of the adult control group, which was representative of the general population, without any difference for either gender or age. We also showed that all children with CHARGE syndrome had olfactory deficiency. Half of them were anosmic, and the others had olfactory residual function (hyposmic). We found no association between olfactory deficiency and feeding behavior, visual or auditory impairment, or intellectual level. Parental subjective evaluations were accurate for only half of the group. All of the MRIs showed anomalies of the olfactory tracts and bulbs varying from moderate hypoplasia to complete aplasia, without any relation between the radiologic and the functional results. Olfaction can be assessed in children, even the young and disabled. Our results support the proposition that rhinencephalon anomalies should be included as a major criterion for the diagnosis of CHARGE syndrome.