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The mammalian brain implements sophisticated sensory processing algorithms along multilayered (deep) neural networks. Strategies that insects use to meet similar computational demands, while relying on smaller nervous systems with shallow architectures, remain elusive. Using Drosophila as a model, we uncover the algorithmic role of odor preprocessing by a shallow network of compartmentalized olfactory receptor neurons. Each compartment operates as a ratiometric unit for specific odor-mixtures. This computation arises from a simple mechanism: electrical coupling between two differently sized neurons. We demonstrate that downstream synaptic connectivity is shaped to optimally leverage amplification of a hedonic value signal in the periphery. Furthermore, peripheral preprocessing is shown to markedly improve novel odor classification in a higher brain center. Together, our work highlights a far-reaching functional role of the sensory periphery for downstream processing. By elucidating the implementation of powerful computations by a shallow network, we provide insights into general principles of efficient sensory processing algorithms.

BACKGROUND: We examined the relationship between baseline olfactory performance and incident significant depressive symptoms and longitudinal depression trajectories in well-functioning older adults. Inflammation and cognitive status were examined as potential mediators. METHODS: Older adults (n = 2 125, 71-82 years, 51% female, 37% Black) completed an odor identification task at Year 3 (our study baseline) of the Health, Aging, and Body Composition study. Cognitive assessments, depressive symptoms, and inflammatory markers were ascertained across multiple visits over 8 years. Discrete-time complementary log-log models, group-based trajectory models, and multivariable-adjusted multinomial logistic regression were employed to assess the relationship between baseline olfaction and incident depression and longitudinal depression trajectories. Mediation analysis assessed the influence of cognitive status on these relationships. RESULTS: Individuals with lower olfaction had an increased risk of developing significant depressive symptoms at follow-up (hazard ratio = 1.04, 95% confidence interval [CI]: 1.00, 1.08). Of the 3 patterns of longitudinal depression scores identified (stable low, stable moderate, and stable high), poorer olfaction was associated with a 6% higher risk of membership in the stable moderate (relative risk ratio [RRR] = 1.06, 95% CI: 1.02, 1.10)/stable high (RRR = 1.06, 95% CI: 1.00, 1.12) groups, compared to the stable low group. Poor cognitive status, but not inflammation, partially mediated the relationship between olfactory performance and incident depression symptom severity. CONCLUSIONS: Suboptimal olfaction could serve as a prognostic indicator of vulnerability for the development of late-life depression. These findings underscore the need for a greater understanding of olfaction in late-life depression and the demographic, cognitive, and biological factors that influence these relationships over time.

The mosquito Aedes aegypti is an important vector of diseases including dengue, Zika, chikungunya, and yellow fever. Olfaction is a critical modality for mosquitoes enabling them to locate hosts, sources of nectar, and sites for oviposition. GABA is an essential neurotransmitter in olfactory processing in the insect brain, including the primary olfactory center, the antennal lobe. Previous work with Ae. aegypti has suggested that antennal lobe inhibition via GABA may be involved in the processing of odors. However, little is known about GABA receptor expression in the mosquito brain, or how they may be involved in odor attraction. In this context, generating mutants that target the mosquitos olfactory responses, and particularly the GABAergic system, is essential to achieve a better understanding of these diverse processes and olfactory coding in these disease vectors. Here we demonstrate the potential of a transgenic line using the QF2 transcription factor, GABA-B1QF2-ECFP, as a new neurogenetic tool to investigate the neural basis of olfaction in Ae. aegypti. Our results show that the gene insertion has a moderate impact on mosquito fitness. Moreover, the line presented here was crossed with a QUAS reporter line expressing the green fluorescent protein and used to determine the location of the metabotropic GABA-B1 receptor expression. We find high receptor expression in the antennal lobes, especially the cell bodies surrounding the antennal lobes. In the mushroom bodies, receptor expression was high in the Kenyon cells, but had low expression in the mushroom body lobes. Behavioral experiments testing the fruit odor attractants showed that the mutants lost their behavioral attraction. Together, these results show that the GABA-B1QF2-ECFP line provides a new tool to characterize GABAergic systems in the mosquito nervous system.

Objective: To investigate the platelet-rich plasma (PRP) effectiveness in patients with a long-lasting postviral olfactory dysfunction (LPOD). Methods: Forty-three consecutive patients with a long-lasting postviral OD were prospectively recruited. The injection of 1 mL of PRP was carried out in both olfactory clefts. The pre- to 6-month post-PRP injection change in olfaction was assessed with the olfactory disorder questionnaire (ODQ) and the threshold, discrimination, and identification (TDI) tests. Results: Forty-three patients received bilateral PRP injections (24 females). The mean age of patients was 58.9 ± 16.8 years. The mean duration of LPOD was 8.7 years. The pre to 6-month post-injection mean TDI significantly improved from 10.3 ± 10.2 to 20.12 ± 12.07 (p = 0.001). The mean ODQ significantly decreased from 29.8 ± 13.0 to 23.4 ± 11.3 (p = 0.013). The average change of the TDI and the ODQ were 9.8 and 6.4, respectively. Age was inversely associated with the 6-month threshold score. Conclusion: PRP appears to be a promising therapeutic strategy for long-lasting postviral OD. Our findings support the conduction of controlled randomized trial in this population of patients. [ABSTRACT FROM AUTHOR]

Objectives: Investigating changes in temporal bone pneumatization (TBP) and paranasal sinus volumes (PSV) across different eras may help understanding not only changes in skull anatomy but also pathophysiology of chronic otitis media and sinusitis, respectively, which are common health problems. Methods: Eight skulls from the second century AD, 20 skulls were from the 10th–11th centuries AD, 20 skulls from the 16th–19th centuries AD, and 60 contemporary skulls were included in this cross-sectional observational study. Using computerized tomography (CT) scans, the PSV were calculated by multiplying the height, width, and antero-posterior distance of the sinuses. TBP was divided into three types. Internal acoustic canal (IAC) length and width, and olfactory cleft (OC) width were measured. Results: No statistically significant differences were found between the paranasal sinus (frontal, maxillary, and sphenoid) volumes between the groups. However, TBP decreased statistically significantly over time on both sides of the skulls (p = 0.001). The contemporary IAC and OC measures were found to be significantly lower on both sides compared to the skulls from the other three eras (p < 0.001 for both). Conclusions: Although no significant change was observed in PSV, decreases were evident in TBP, OC width and IAC length and width over time. It appears a fair inference that changes in size of OC and IAC might be another indication of the fact that olfaction and hearing were more vital for survival in old eras. Since we do not know incidence of chronic ear problems in old eras, we cannot speculate outcome of increased TBP in terms of developing chronic ear diseases. On the contrary, increased TBP was likely to play a protective role in traumas in old ears. Additionally, the environmental influences may be crucial role in the development of paranasal sinuses. [ABSTRACT FROM AUTHOR]

• A reduced functional connectivity of the olfactory system is observed in PD. • Hyposmia and decreased functional connectivity is also present in MCI. • Males showed increased functional connectivity than females in OFC. • Decreased functional connectivity particularly involves the limbic system. • Functional connectivity of olfactory network can help to identify PD. Olfactory dysfunction is an early sign of such neurodegenerative diseases as Parkinson's (PD) and Alzheimer's (AD), and is often present in Mild Cognitive Impairment (MCI), a precursor of AD. Understanding neuro-temporal relationships, i.e., functional connectivity, between olfactory eloquent structures in such disorders, could shed light on their basic pathophysiology. To this end, we employed region-based analyses using resting-state functional magnetic resonance imaging (rs-fMRI) obtained from cognitively normal (CN), MCI, and PD patients with cognitive impairment (PD-CogImp). Using machine learning (linear and ensemble learning), we determined whether the identified functional patterns could classify abnormal function from normal function. Olfaction, as measured by objective testing, was found to be most strongly associated with diagnostic status, emphasizing the fundamental association of this primary sensory system with these conditions. Consistently lower functional connectivity was observed in the PD-CogImp cohort compared to the CN cohort among all identified brain regions. Differences were also found between PD-CogImp and MCI at the level of the orbitofrontal and cingulate cortices. MCI and CN subjects had different functional connectivity between the posterior orbitofrontal cortex and thalamus. Regardless of study group, males showed significantly higher connectivity than females in connections involving the orbitofrontal cortex. The logistic regression model trained using the top discriminatory features revealed that caudate was the most involved olfaction-related brain structure (accuracy = 0.88, Area under the Receiver operator characteristic curve of 0.90). In aggregate, our study demonstrates that resting functional connectivity among olfactory eloquent structures has potential value in better understanding the pathophysiology of several neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Background: Intranasal trigeminal function is important in detecting environmental stimuli. The impact of age-associated chemosensory dysfunction upon taste and olfaction is well described, but an understanding of trigeminal loss (chemesthesis) is lacking. Objective: The goal of this study was to characterize trigeminal function in a cohort of older adults and explore potential impacts. Methods: Twenty-eight participants over 50 years of age were recruited from the community as part of an aging cohort study. This nested cohort completed chemosensory questionnaires, patient-reported outcome measures (PROMs), and psychophysical testing for taste (taste strips), olfaction (Sniffin' Sticks), and trigeminal function (eucalyptol lateralization). Data were analyzed for associations between trigeminal function, olfactory, and taste psychophysical performance, patient-reported metrics, and demographic risk factors. Results: Patient-reported trigeminal impairment is less severe than other chemosensory loss, with mean visual analog scores (VAS, rated 0-100 from least to most severe) for smell (32.9 ± 34.2), taste (20.6 ± 28.4), and trigeminal sensation (9.5 ± 12.8). Despite low VAS scores, psychophysical trigeminal dysfunction was present in 10 (35.7%) subjects. Psychophysical olfactory and taste dysfunction were present in 16 (57.1%) and eight (28.6%) participants respectively. Hypercholesterolemia was associated with psychophysical trigeminal dysfunction (mean lateralization performance in hypercholesterolemia 57.7% ± 17.1 vs. 74.1% ± 10.4, p =.008). Conclusion: Intranasal trigeminal impairment is present in nearly one-third of aging adults when assessed by psychophysical methods but is under-recognized. Hyperlipidemia may be associated with trigeminal impairment. Future inquiries should better characterize these findings in larger and prospective cohorts. [ABSTRACT FROM AUTHOR]

Objective: To compare, using state‐of‐the‐art psychophysical tests, the olfactory function of patients complaining and not complaining of olfactory hypersensitivity. Study Design: Retrospective cross‐sectional. Setting: The Smell and Taste Center at the University of Pennsylvania. Methods: University of Pennsylvania Smell Identification Test (UPSIT) scores were obtained from 148 patients complaining of hyperosmia and 494 patients with no such complaints; detection threshold test scores were obtained from 77 and 483 patients of these respective groups. The effects of subject group, age, and sex on the test scores were assessed using analyses of variance. Categorical variables were evaluated by χ2. Responses to items within a detailed intake questionnaire, for example, the Beck Depression Inventory (BDI‐II), were also evaluated. Results: Unexpectedly, those complaining of hyperosmia had lower olfactory test scores than those with no such complaints (respective UPSIT means [95% confidence interval [CIs]] = 27.86 (26.85, 28.87) and 32.19 (31.67, 32.71); P <.001; respective threshold means (log vol/vol) = −4.49 (−4.89, −4.09) and −5.22 (−5.36, −5.06); P <.001). Remarkably, 70.95% of the self‐identified hyperosmics exhibited mild to severe microsmia. The hyposmia complainers also exhibited elevated BDI scores (11.02 [9.53, 12.51] vs 7.58 [6.80, 8.34]). Conclusion: When objectively tested, many patients who complain of hypersensitivity to odors are actually less sensitive to them. The basis of this phenomenon is unclear. It could reflect the presence of emotionally disturbing altered smell sensations, or one or more comorbidities, such as hypochondria or osmophobia. These findings point to the importance of objective testing of persons with complaints of chemosensory dysfunction and reiterate the inaccuracy of self‐reports. [ABSTRACT FROM AUTHOR]

Sea squirts (Tunicata) are chordates and develop a swimming larva with a small and defined number of individually identifiable cells. This offers the prospect of connecting specific stimuli to behavioral output and characterizing the neural activity that links these together. Here, we describe the development of a microfluidic chip that allows live larvae of the sea squirt Ciona intestinalis to be immobilized and recorded. By generating transgenic larvae expressing GCaAMP6m in defined cells, we show that calcium ion levels can be recorded from immobilized larvae, while microfluidic control allows larvae to be exposed to specific waterborne stimuli. We trial this on sea water carrying increased levels of carbon dioxide, providing evidence that larvae can sense this gas. Research Highlights: Development of a microfluidic chip in which Ciona larvae can be immobilized, exposed to controlled stimuli, and recorded.A transgenic construct was designed to drive expression of the live cell calcium ion reporter GCaMP in Ciona palp cells and other sensory cells.Exposure of Ciona larvae to carbon dioxide‐enriched sea water leads to detectable changes in GCaMP activity. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusion Olfactory dysfunction (OD) in the elderly is common and associated with numerous comorbidities, yet often underrecognized. This study sought to develop an instrument for widespread screening of this condition.Demographic factors, comorbidities, and olfactory‐related questions were examined in a focus group (N = 20) and development cohort (N = 190). The 4‐item Concise Aging adults Smell Test (4‐CAST) screening instrument was then developed to predict OD on Sniffin Sticks testing. An independent validation cohort (N = 147) was then examined to confirm ability of the 4‐CAST to predict OD on Smell Identification Test 40 (SIT40).The most important variables for predicting olfactory loss in older subjects were age, type II diabetes status, Visual Analog Scale (VAS) of overall rating of smell, and VAS of impact of smell upon safety. In the development cohort, the 4‐CAST model yielded predictive probability (area under the curve) of 0.805 (p < 0.001) for predicting the bottom 25th percentile on Sniffin Sticks. Results were similar in the validation cohort, as the 4‐CAST accurately classified 83.8% subjects (area under the curve [AUC] 0.789, p < 0.001) in the bottom 25th percentile of SIT40 testing. The 4‐CAST was able to accurately classify 89.4% of subjects with anosmia.The 4‐CAST is a quick screening instrument for predicting OD in older adults and has similar performance characteristics in independent populations using the two most common validated olfactory tests. Given the high prevalence of unrecognized olfactory loss in this population, this can be a useful tool for practitioners to determine which subjects may benefit from more extensive olfactory testing. [ABSTRACT FROM AUTHOR]

Olfactory loss accompanies at least 139 neurological, somatic, and congenital/hereditary conditions. This observation leads to the question of whether these associations are correlations or whether they are ever causal. Temporal precedence and prospective predictive power suggest that olfactory loss is causally implicated in many medical conditions. The causal relationship between olfaction with memory dysfunction deserves particular attention because this sensory system has the only direct projection to memory centers. Mechanisms that may underlie the connections between medical conditions and olfactory loss include inflammation as well as neuroanatomical and environmental factors, and all 139 of the medical conditions listed here are also associated with inflammation. Olfactory enrichment shows efficacy for both prevention and treatment, potentially mediated by decreasing inflammation. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusion Chronic rhinosinusitis with nasal polyposis (CRSwNP) is associated with a high rate of disease recurrence following endoscopic sinus surgery (ESS). Type 2 disease is associated with a higher incidence of recurrence and is believed to impact disease resolution via interference with epithelial healing and pathogen immunity. We wished to verify if perioperative control of Type 2 inflammation with an anti‐IL4/IL13 targeting monoclonal antibody and during the resolution period following surgery leads to better control of the disease long term.In this prospective, placebo‐controlled, double‐blinded trial. Thirty adult subjects with recurrent CRSwNP underwent ESS plus or minus 14 weeks of perioperative dupilumab, initiated 4 weeks (two injections) pre‐ESS. Subjective and objective parameters of nasal patency, olfaction, quality of life (QoL), and adverse events were monitored up to 52 weeks post‐ESS. Microbiological culture was performed to characterize pathogens colonization under both conditions.ESS safely improved subjective and objective measures of nasal patency, olfaction, and QoL in both groups. Olfaction was conserved longer in the dupilumab‐treated group, with 33.3% of subjects presenting anosmia at 12 months after ESS in the dupilumab group compared to 50.0% with placebo. This was associated with persistent decreases in serum IgE, which were not seen with placebo treatment. No unusual safety signals were observed.Short‐course adjuvant perioperative treatment with dupilumab is associated with improved long‐term olfactory outcomes and persistent lowering of serum IgE. [ABSTRACT FROM AUTHOR]

Control and elimination of invasive fishes, like carps (Order Cypriniformes), may be possible by using chemical stimuli to congregate them for removal. To this end, we tested behavioral responses of grass (Ctenopharyngodon idella), bighead (Hypophthalmichthys nobilis), and silver carp (H. molitrix) to L‐alanine, L‐arginine, L‐glutamic acid, and L‐aspartic acid. In grass carp, the first three amino acids have been shown to be beneficial for growth, and all four produce a strong olfactory response in this species. This study used pairs of conspecific fish in a video‐recorded, sound‐insulated, clear acrylic, tube‐shaped tank; during trials, an amino acid stimulus was delivered at one end of that tank. Changes in space use, velocity, and acceleration across all amino acids differed significantly among species. Changes in space use by grass carp indicated avoidance of only two amino acids, L‐alanine and L‐aspartic acid. There was no evidence for attraction to amino acids for grass or silver carp. For bighead carp, change in spatial use on exposure to amino acids indicated attraction across the four amino acids. This attraction was enhanced by lowered velocity. Our results suggested that olfactory sensitivity does not directly translate to behavioral responses. Other sensory cues, for example tactile, visual, and/or taste, may mediate the selective foraging of grass carp. Amino acids may serve as a better olfactory attractant for bighead carp compared to grass or silver carp. [ABSTRACT FROM AUTHOR]

Neurodegenerative diseases such as Alzheimer's disease and polyglutamine diseases are characterized by abnormal accumulation of misfolded proteins, leading to neuronal dysfunction and subsequent neuron death. However, there is a lack of studies that integratemolecular, morphological, and functional analyses in neurodegenerative models to fully characterize these time-dependent processes. In this study, we used C. elegans models expressing Ab1-42 and polyglutamine to investigate early neuronal pathogenic features in olfactory neurons. Both models demonstrated significant reductions in odor sensitivity in AWB and AWC chemosensory neurons as early as day 1 of adulthood, while AWA chemosensory neurons showed no such decline, suggesting cell-type-specific early neuronal dysfunction. At the molecular level, Ab1-42 or Q40 expression caused age-dependent protein aggregation and morphological changes in neurons. By day 6, both models displayed prominent protein aggregates in neuronal cell bodies and neurites. Notably, AWB neurons in both models showed significantly shortened cilia and increased instances of enlarged cilia as early as day 1 of adulthood. Furthermore, AWC neurons expressing Ab1-42 displayed calcium signaling defects, with significantly reduced responses to odor stimuli on day 1, further supporting early behavioral dysfunction. In contrast, AWA neuron did not exhibit reduced calciumresponses, consistent with the absence of detectable decreases in olfactory sensitivity in these neurons. These findings suggest that decreased calcium signaling and dysfunction in specific sensory neuron subtypes are early indicators of neurodegeneration in C. elegans, occurring prior to the formation of visible protein aggregates. We found that the ER unfolded protein response (UPR) is significantly activated in worms expressing Ab1-42. Activation of the AMPK pathway alleviates olfactory defects and reduces fibrillar Ab in these worms. This study underscores the use of C. elegans olfactory neurons as a model to elucidate mechanisms of proteostasis in neurodegenerative diseases and highlights the importance of integrated approaches. [ABSTRACT FROM AUTHOR]

Females control the paternity of their offspring by selectively mating with males they perceive to be of high quality. In species where females mate with multiple males in succession, females may bias offspring paternity by favoring the sperm of one male over another, a process known as cryptic female choice. 1 While evidence of cryptic female choice exists in multiple taxa, the mechanisms underlying this process have remained difficult to unravel. 2 Understanding cryptic female choice requires demonstration of a female-driven post-mating bias in sperm use and paternity and a causal link between this bias and male cues. 3 In this study, we present evidence of cryptic female choice in female Drosophila melanogaster. Through experiments utilizing transgenic males expressing fluorescent sperm, we observed that exposure to attractive males between matings prompts females to expel the ejaculate of their initial mate more rapidly than in the presence of less attractive males. While doing so, females exhibit a bias in sperm storage against their first mate, thereby favoring the paternity of their subsequent mate. Our findings reveal that females adjust the timing of ejaculate expulsion in response to male pheromones in their environment, specifically heptanal and 11- cis -vaccenyl acetate, which are sensed by females through specific odorant receptors. We provide a cryptic female choice mechanism allowing a female to modulate the share of paternity of her first mate depending on the sensing of the quality of potential mates in her environment. These findings showcase that paternity can be influenced by events beyond copulation. [Display omitted] • D. melanogaster females exert cryptic mate choice • Females eject their first mate's ejaculate faster in the presence of attractive males • Females exposed to attractive males bias sperm storage against their first mate • Male pheromones heptanal and cVA are sufficient to shorten ejection latency Doubovetzky et al. present evidence of cryptic female choice in Drosophila melanogaster. Females exposed to pheromones of attractive males expedite ejaculate ejection from their first mate, favoring subsequent mates' sperm. This work highlights that female fruit flies can influence paternity of their offspring through post-copulatory mechanisms. [ABSTRACT FROM AUTHOR]

For organisms tracking a chemical cue to its source, the motion of their surrounding fluid provides crucial information for success. Swimming and flying animals engaged in olfaction-driven search often start by turning into the direction of an oncoming wind or water current. However, it is unclear how organisms adjust their strategies when directional cues are absent or unreliable, as is often the case in nature. Here, we use the genetic toolkit of Drosophila melanogaster to develop an optogenetic paradigm to deliver temporally precise "virtual" olfactory experiences for free-flying animals in either laminar wind or still air. We first confirm that in laminar wind flies turn upwind. Furthermore, we show that they achieve this using a rapid (∼ 100 ms) turn, implying that flies estimate the ambient wind direction prior to "surging" upwind. In still air, flies adopt a remarkably stereotyped "sink and circle" search state characterized by ∼ 60° turns at 3–4 Hz, biased in a consistent direction. Together, our results show that Drosophila melanogaster assesses the presence and direction of ambient wind prior to deploying a distinct search strategy. In both laminar wind and still air, immediately after odor onset, flies decelerate and often perform a rapid turn. Both maneuvers are consistent with predictions from recent control theoretic analyses for how insects may estimate properties of wind while in flight. We suggest that flies may use their deceleration and "anemometric" turn as active sensing maneuvers to rapidly gauge properties of their wind environment before initiating a proximal or upwind search routine. [Display omitted] • Activating Orco+ neurons in flying Drosophila elicits stereotyped plume tracking • In still air, flies use a novel search strategy: sink and circle • In wind, flies orient upwind with rapid ∼100-ms turns • We propose that flies use active sensing maneuvers to gauge wind properties Here, Stupski and van Breugel develop an optogenetic paradigm to precisely control the olfactory experiences of freely flying Drosophila melanogaster. They then investigate olfactory search in the absence of wind and describe "sink and circle." Finally, they describe an active sensing maneuver for how flies may measure the wind while flying. [ABSTRACT FROM AUTHOR]

Objective: The present study objectived to investigate the influence of Ramadan fasting (RF) on olfactory function. Methods: Sixty‐two participants were included in the current prospective study. The odor threshold and identification performances were determined by using the Connecticut Chemosensory Clinical Research Center (CCCRC) test initially (day 0) and on the first and last day (30th) of RF. Body weight (BW)s were measured initially and at the end of the study. The results were analyzed statistically. Results: The average of baseline and last‐day BWs were 78.38 ± 12.96 and 78.36 ± 12.39 kg, respectively. No significant difference was determined in terms of BWs (p =.932, p >.05). In the evaluation of CCCRC test outcomes, significant differences were observed in the scores of butanol thresholds (p =.0001), odor identification (p =.0001), food‐related odors identification (p =.0001), and the number of normosmic individuals (p =.0001) at different times (p <.05). The thresholds scores (p =.0001, p =.0001), the identification scores (p =.0001, p =.0001), food‐related odors identification scores (p =.0001, p =.0002), and the number of normomic individuals (p =.001, p =.001) detected on 30th day were significantly higher than on 0th and 1st days; respectively (p <.05). Additionally, the threshold scores (p =.0001), the identification scores (p =.003), food‐related odors identification scores (p =.007), and the number of normosmic individuals (p =.018) detected on day 1 were significantly higher than on day 0 (p <.05). Conclusion: The current study demonstrated that Ramadan fasting enhances the olfactory detection threshold and odor identification scores, significantly improving the identification of food‐related odors. The results may indicate that Ramadan fasting improves olfactory performance. Level of evidence: Level II. [ABSTRACT FROM AUTHOR]

Gravid culicine mosquitoes rely on olfactory cues for selecting breeding sites containing organic detritus. While this capacity of the mosquitoes is used for surveillance and control, the current methodology is unwieldy, unreliable and expensive in time and labour. This study evaluated the dose-dependent attraction and oviposition response of gravid Culex quinquefasciatus to alfalfa infusions. Through combined chemical and electrophysiological analyses, bioactive volatile organic compounds (VOCs) in the headspace of alfalfa infusions, eliciting attraction, were identified. While phenolic and indolic compounds were the most abundant bioactive VOCs, additional VOCs, including a monoterpene, were required to elicit a significant behavioural response to the synthetic odour blend of alfalfa infusions. Comparative analysis with the commercially available mosquito oviposition pheromone (MOP) was also conducted demonstrating that this standardised synthetic alfalfa infusion odour blend offers a promising lure for targeted surveillance and control of Culex mosquitoes, which may contribute to disease prevention and public health protection. [ABSTRACT FROM AUTHOR]

Endoscopic endonasal surgical resection is an effective therapeutic approach for olfactory neuroblastoma (ONB). Unilateral excision of ONBs with limited extension has been reported with the purpose of preserving olfactory function. We aimed to review implications of surgical management, olfactory preservation feasibility, and survival outcomes in patients who underwent endoscopic unilateral resection of ONB. A systematic literature review was conducted using the search terms [("Olfactory neuroblastoma") OR ("Esthesioneuroblastoma")] AND [("Unilateral resection") OR ("Olfaction preservation")]. Studies reporting cases of unilateral ONB endoscopic resection with postoperative olfaction assessment were included. Concurrently, records of patients who met inclusion criteria at our institution were reviewed retrospectively. The survival and olfactory outcomes were analyzed in both cohorts. Thirty-three patients were identified in the published literature. Twenty-three (69.7%) reported postoperative olfaction preservation. Olfactory function after surgery did not show an association with Kadish stage (P = 0.128). No evidence of disease was observed at the latest follow-up in this group of patients. Nine patients who met inclusion criteria were identified at our institution. The extent of resection influenced the level of olfaction preservation when cribriform plate and nasal septum resection coexisted (P = 0.05). A single patient at our institution developed recurrence after being lost to follow-up for 22 months. Olfaction preservation can be achieved in patients who undergo endoscopic unilateral resection and adjuvant radiotherapy. The extent of resection should aim for negative margins, particularly in the midline. Larger studies are required to assess the risk of contralateral microscopic disease, and, hence, close follow-up is advised. [ABSTRACT FROM AUTHOR]

Feeding behavior is critical for insect survival and fitness. Most researchers have explored the molecular basis of feeding behaviors by identifying and elucidating the function of olfactory receptors (ORs) and gustatory receptors (GRs). Other types of genes, such as transcription factors, have rarely been investigated, and little is known about their potential roles. The silkworm (Bombyx mori) is a well‐studied monophagic insect which primarily feeds on mulberry leaves, but the genetic basis of its monophagy is still not understood. In this report, we focused on a transcription factor encoded by the Zfh3 gene, which is highly expressed in the silkworm central and peripheral nervous systems, including brain, antenna, and maxilla. To investigate its function, Zfh3 was abrogated using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9) mutagenesis. Since Zfh3 knockout homozygotes are not viable, we studied feeding behavior in heterozygotes, and found that disruption of Zfh3 affects both gustation and olfaction. Mutant larvae lose preference for mulberry leaves, acquire the ability to consume an expanded range of diets, and exhibit improved adaptation to the M0 artificial diet, which contains no mulberry leaves. These results provide the first demonstration that a transcription factor modulates feeding behaviors in an insect. [ABSTRACT FROM AUTHOR]

The use of insecticides, primarily pyrethroids, is a pivotal strategy for mosquito control globally. Bioallethrin, the first commercially available volatile pyrethroid, can elicit spatial (i.e., noncontact) repellency to mosquitoes through the coactivation of olfactory receptor neurons and sodium channels. However, the olfactory mechanism of the repellency elicited by bioallethrin in mosquitoes is still unclear. Here, we demonstrated the involvement of AsOBP1 in the bioallethrin repellency in Anopheles sinensis, one of the main vectors of vivax malaria in China and other Southeast Asian countries. The behavioral and electrophysiological analyses in AsOrco−/− mutant found that the spatial repellency elicited by bioallethrin depended on the odorant receptor (OR)‐mediated olfactory pathway. Furthermore, the repellency was reduced in the AsOBP1−/− mutant and a pyrethroid‐resistant strain, in which the expression of AsOBP1 was significantly decreased. Moreover, recombinant AsOBP1 protein bound to bioallethrin in an in vitro competition assay. These results indicate that activation of the AsOBP1‐mediated olfactory pathway is an important component of bioallethrin repellency. Our research lays the foundation for further elucidation into the olfactory mechanism of bioallethrin repellency and the behavioral modifications of pyrethroid‐resistant mosquitoes. [ABSTRACT FROM AUTHOR]

Insulin receptors (InR) are an integral component of the insulin/insulin‐like growth factor signaling pathway, which plays a vital role in insect development, lifespan, reproduction, and olfactory sensitivity. However, whether InR participate in the peripheral olfactory system of insects remains unclear. Recently, we found that 2‐heptanone (2‐HT) affects AcerInR expression, the gene for an InR protein, in Apis cerana cerana. We then examined the spatiotemporal expression profile of the gene in A. cerana cerana. The mRNA of AcerInR was primarily expressed in the antennae, wings, and legs of forager bees, which are probable chemosensory tissues. The results of fluorescence competitive binding assays, combined with site‐directed mutagenesis, demonstrated that AcerOBP6 and AcerOBP14 exhibit strong binding affinities to 2‐HT. Furthermore, after foragers were fed with double‐stranded AcerInR, the expression levels of AcerOBP6 and AcerOBP14 decreased significantly, as did the electroantennogram responsiveness to 2‐HT and some other odorants. In conclusion, our findings provide a foundation for understanding the involvement of AcerInR in the odor perception of A. cerana cerana. Moreover, they offer novel insights into the olfactory recognition mechanism in insects. [ABSTRACT FROM AUTHOR]

Water‐choice experiments were conducted using glass eels of Anguilla japonica and A. marmorata, which coexist in subtropical East Asian rivers. The results of the present study, together with those of previous water‐choice experiments, suggest that salinity enhances the odor preferences of glass eels. Compared to A. marmorata glass eels, A. japonica glass eels were more strongly attracted to water collected from a leaf detritus‐accumulating backwater area than to normal river water under the same salinity conditions. These results suggest that interspecific differences in odor preferences may facilitate their habitat segregation. [ABSTRACT FROM AUTHOR]

Mammalian olfactory sensory neurons (OSNs) generate an odorant‐induced response by sequentially activating two ion channels, which are in their ciliary membranes. First, a cationic, Ca2+‐permeable cyclic nucleotide‐gated channel is opened following odorant stimulation via a G protein‐coupled transduction cascade and an ensuing rise in cAMP. Second, the increase in ciliary Ca2+ opens the excitatory Ca2+‐activated Cl− channel TMEM16B, which carries most of the odorant‐induced receptor current. While the role of TMEM16B in amplifying the response has been well established, it is less understood how this secondary ion channel contributes to response kinetics and action potential generation during single as well as repeated stimulation and, on the other hand, which response properties the cyclic nucleotide‐gated (CNG) channel determines. We first demonstrate that basic membrane properties such as input resistance, resting potential and voltage‐gated currents remained unchanged in OSNs that lack TMEM16B. The CNG channel predominantly determines the response delay and adaptation during odorant exposure, while the absence of the Cl− channels shortens both the time the response requires to reach its maximum and the time to terminate after odorant stimulation. This faster response termination in Tmem16b knockout OSNs allows them, somewhat counterintuitively despite the large reduction in receptor current, to fire action potentials more reliably when stimulated repeatedly in rapid succession, a phenomenon that occurs both in isolated OSNs and in OSNs within epithelial slices. Thus, while the two olfactory ion channels act in concert to generate the overall response, each one controls specific aspects of the odorant‐induced response. Key points: Mammalian olfactory sensory neurons (OSNs) generate odorant‐induced responses by activating two ion channels sequentially in their ciliary membranes: a Na+, Ca2⁺‐permeable cyclic nucleotide‐gated (CNG) channel and the Ca2⁺‐activated Cl⁻ channel TMEM16B.The CNG channel controls response delay and adaptation during odorant exposure, while TMEM16B amplifies the response and influences the time required for the response to reach its peak and terminate.OSNs lacking TMEM16B display faster response termination, allowing them to fire action potentials more reliably during rapid repeated stimulation.The CNG and TMEM16B channels have distinct and complementary roles in shaping the kinetics and reliability of odorant‐induced responses in OSNs. [ABSTRACT FROM AUTHOR]

Background: Amidst the rise of frailty among a globally aging population, olfactory decline has emerged as a harbinger of frailty and mortality in population‐level studies. However, the relationships between frailty and the olfactory subdomains of identification (OI), discrimination (OD), and threshold (OT) remain unexplored. This study prospectively examined the association between olfactory subdomains and the physical frailty phenotype (PFP) to investigate olfactory evaluation as a means of frailty screening. Methods: A case‒control study of 45 frail and 45 non‐frail individuals matched by age and sex. OT, OD, OI (range 0‒16), and composite sum (threshold, discrimination, and identification scores [TDI], range 0‒48) were measured with Sniffin' Sticks. PFP was defined by presence of three or more criteria: physical inactivity, self‐reported exhaustion, muscle weakness, slow gait, and unintentional weight loss. Conditional logistic regression evaluated associations between olfactory subdomains and frailty. Results: Ninety individuals with mean age of 83.1 ± 4.9 years, 60% female (n = 54), and 87.8% white (n = 79) were included. Olfactory scores were significantly lower in the frail group for OI (9.2 vs. 12.1, p < 0.001), OD (8.1 vs. 11.6, p < 0.001), OT (4.4 vs. 8.5, p < 0.001), and TDI (21.7 vs. 32.2, p < 0.001) than in the non‐frail group. A single‐point decrease in olfactory score was associated with increased odds of frailty in OT (odds ratio [OR]: 2.21, 95% confidence interval: [1.22, 3.98]), OD (OR: 2.19, 95% CI: [1.32, 3.65]), OI (OR: 2.29, 95% CI: [1.19, 4.39]), and TDI (OR: 1.54, 95% CI: [1.14, 2.08]). Conclusion: The robust association between olfactory subdomain scores and frailty suggests that olfaction may be an accessible signifier of frailty. Future studies should investigate this relationship longitudinally to assess predictive relationships. [ABSTRACT FROM AUTHOR]

Introduction: Despite effects on quality of life from olfactory and gustatory dysfunction (OD and GD), screening practices are limited, and patients' self‐reporting of symptoms remains the only way to understand the burden of chemosensory dysfunction (CSD). Using a large population‐based database, we sought to understand factors leading to reduced likelihood of discussing CSD with a provider. Methods: The 2013‒2014 National Health and Nutrition Examination Survey (NHANES) chemosensory protocol was queried for factors influencing discussion of OD/GD with a healthcare provider. Sociodemographic, comorbidity, and objective OD/GD testing results were assessed with a multivariate analysis. Results: Out of 146.1 million US adults, there were an estimated 41.4 million individuals with self‐reported OD/GD in the prior 12 months (28.3%). A total of 86.8% of participants did not discuss their problem with a healthcare provider. Men were about half as likely to speak with a healthcare provider (odds ratio [OR] 0.42; 0.26–0.66; p < 0.001) and those with a college education were about nine times more likely to discuss the problem compared to those with less than a ninth‐grade educational achievement (OR 8.83; 1.86–41.98; p = 0.02). Those with objective confirmation of CSD were still unlikely to speak with a provider (OR 0.77; 0.44–1.33; p = 0.36). Conclusion: Men and those with less education are less likely to discuss OD/GD with a healthcare provider. These populations tend to be at increased risk for CSD, and there are severe downstream health and quality of life implications related to CSD. Dedicated screening and increased public awareness are critical to ensure more equitable care. [ABSTRACT FROM AUTHOR]

Odor hedonic perception (pleasant/unpleasant character) is considered to be the first and one of the most important dimensions in olfaction and is known to be highly variable and dependent on several factors related to the stimulus, individual characteristics, and context. Although numerous experimental studies have been published on this topic, there is no comprehensive general review on the variability in odor hedonic perception. Therefore, the aim of this article was to describe and detail all the factors involved in the variability in odor hedonic perception. Stimulus properties-related variability includes the concentration/intensity and the physicochemical properties. Individual-related variability includes sex, age, and physiological state characteristics, while context-related variability involves factors associated with the stimulation context, such as stimulation pathway, exposure frequency, verbal influences, cross-modal associations, hedonic contrast, and cultural background. Subsequently, a section is devoted to the brain processing of odor hedonicity, although its role in odor hedonic variability is largely unknown. Finally, the article discusses the relationship between the hedonic qualities of odors and the resulting behavioral responses in both animals and humans. [ABSTRACT FROM AUTHOR]

Odor detection in insects is largely mediated by structures on antennae called sensilla, which feature a strongly conserved architecture and repertoire of olfactory sensory neurons (OSNs) and various support cell types. In Drosophila, OSNs are tightly apposed to supporting cells, whose connection with neurons and functional roles in odor detection remain unclear. Coupling mechanisms between these neuronal and non-neuronal cell types have been suggested based on morphological observations, concomitant physiological activity during odor stimulation, and known interactions that occur in other chemosensory systems. For instance, it is not known whether cell–cell coupling via gap junctions between OSNs and neighboring cells exists, or whether hemichannels interconnect cellular and extracellular sensillum compartments. Here, we show that innexins, which form hemichannels and gap junctions in invertebrates, are abundantly expressed in adult drosophilid antennae. By surveying antennal transcriptomes and performing various immunohistochemical stainings in antennal tissues, we discover innexin-specific patterns of expression and localization, with a majority of innexins strongly localizing to glial and non-neuronal cells, likely support and epithelial cells. Finally, by injecting gap junction-permeable dye into a pre-identified sensillum, we observe no dye coupling between neuronal and non-neuronal cells. Together with evidence of non-neuronal innexin localization, we conclude that innexins likely do not conjoin neurons to support cells, but that junctions and hemichannels may instead couple support cells among each other or to their shared sensillum lymph to achieve synchronous activity. We discuss how coupling of sensillum microenvironments or compartments may potentially contribute to facilitate chemosensory functions of odor sensing and sensillum homeostasis. [ABSTRACT FROM AUTHOR]

Because of the brief and cryptic nature of predatory behavior, sentinel prey has been widely adopted as an indirect way to identify predators and understand trophic interactions. However, sentinel prey presents only static visual cues, potentially biasing toward visually oriented predators while ignoring those that utilize other sensory cues for foraging. Despite this, the effectiveness of sentinel prey has rarely been tested. In this study, we focused on the weaver ant Oecophylla smaragdina Fabricius (Hymenoptera: Formicidae), a keystone predator widespread in the Asian and Australian tropics. As this species has large eyes and is known to visually navigate in its arboreal habitats, we hypothesized that it relies on visual cues to forage and that its predatory behavior will be captured by caterpillar‐shaped sentinel prey. Ants were collected as colonies, and preference trials on baits were conducted using combinations of olfactory and static visual cues, including the caterpillar shape. Surprisingly, O. smaragdina showed little or no preference for baits in the absence of olfactory cues and did not differentiate the shapes of baits regardless of olfactory cues. Our results indicate that O. smaragdina is likely to make predatory decisions based primarily on olfactory cues, whereas visual cues might be used for other behaviors. Furthermore, O. smaragdina is likely to be left out by the predation studies using sentinel prey models, which is particularly alarming considering the dominant role of this species in the trophic interactions of tropical rainforests. Our study demonstrates that morphological characteristics, arboreal habitats, and visually oriented behavior do not necessarily suggest the use of static visual cues for predatory decisions. We suggest that sentinel prey models should not be used alone when the dominant predators are unlikely to use visual cues to make predatory decisions. [ABSTRACT FROM AUTHOR]

Converging global trends (digitization, globalization, datafication) have influenced all aspects of children's literacies, including children's picturebooks. The recent turn towards embodied, affective and sensory literacies, stimulated our interest in multisensory picturebooks that engage all children's senses, including the sense of smell (olfaction). Olfactory children's picturebooks demand new forms of literary conversations, which capitalise on unique properties of odours and integrate these with stories. Drawing on a systematic search of children's picturebooks about, and with, smell, in paper-based and digital formats, we identified three principal ways in which olfaction is currently embedded in children's picturebooks: 1, as an add-on to depiction of objects (including foods, plants) and places, 2, as a device to introduce humour into a story, and 3, as an engagement tool for children's active participation in the story. We mobilise Sipe's (2008) concept of seven constituting elements in children's picturebooks to describe how current olfactory picturebooks apply the elements in their design and make recommendations for future development of children's olfactory picturebooks. Reflecting on the generative potential of literary theories and olfactory power to stimulate children's non-linguistic embodied interactions with picturebooks, we propose some extensions to the current olfactory picturebook landscape. [ABSTRACT FROM AUTHOR]

This study is a researcher-practitioner action inquiry which was used to explore children's sensory experiences with a focus on the sense of smell (olfaction). We critically considered the early childhood theories that positioned children's sensory learning within equitable, socially just early childhood approaches and connected them to an action inquiry approach. The data comprise a systematic documentation of the odours experienced by children in the classroom, an olfactory log of the kindergarten space as well as children's 'smellmaps' from outdoor 'smellwalks'. We interpret children's olfactory experiences and reflect on the ways in which the multi-sensory approach to literacy might extend the field's understanding of the multi-dimensional ways in which educational researchers and practitioners can cultivate their joint inquiries in early childhood education. We present implications for adopting an olfactory researcher-practitioner collaboration in early childhood and conclude that such an approach exemplifies a sensorially sensitive early childhood curriculum. [ABSTRACT FROM AUTHOR]

Background Prospective studies comparing quality-of-life and olfaction in patients undergoing endoscopic uni-nostril versus bi-nostril trans-sphenoidal pituitary surgery have not been published. Methods We prospectively compared olfaction and quality-of-life at baseline and at 3 to 6 months follow-up using the Anterior Skull Base Nasal Inventory-12 (ASK-12) questionnaire, composite olfaction score, and Lund–Kennedy Endoscopic Score (LKES) in 43 patients who underwent endoscopic excision of pituitary adenoma with either a uni-nostril (24 patients) or a bi-nostril (19 patients) approach. Results Baseline data for both groups were comparable. In the uni-nostril group, ASK-12 and LKES scores were not significantly different at follow-up when compared with the preoperative scores. In the bi-nostril group, there was a significant postoperative worsening of ASK-12 scores (mean: 3.2 vs. 5.3; p = 0.04) and the LKES (mean: 2.9 vs. 6.6; p = 0.01). Composite olfaction score was not significantly affected postoperatively with either approach. Nasal complications were also more in the bi-nostril group (5/18, 27.8% vs. 1/23, 4.3%) but this was not statistically significant (p = 0.07). Conclusion Both approaches preserve olfactory function but the uni-nostril approach is associated with better postoperative quality-of-life and endoscopic scores and subjective olfaction outcomes. At least in short term, the postoperative morbidity is higher in the bi-nostril approach compared with the uni-nostril approach. Although preference for a particular approach is related to a surgeon's preference, preoperative counselling of the patients regarding sinonasal morbidity is important. [ABSTRACT FROM AUTHOR]

Sclerodermus cereicollis is a European flat wasp ectoparasitoid of some longhorn beetle species. This species is important as a suitable biological control agent against xylophagous pests. To better understand its chemical ecology, the ultrastructure of the antennal sensilla of the adult was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The sensilla are located mainly in the ventro‐medial side of the antennae. We report a clearly sexual dimorphism with respect to antennae length, and to types, number, and distribution of chemosensilla. The antennae in males are significantly longer than those of females. We describe in detail the external and internal structure of different chemoreceptors represented by sensilla placodea, long sensilla basiconica, multiporous sensilla chaetica, grooved sensilla ampullacea, uniporous grooved sensilla chaetica. The potential involvement of the different kinds of chemoreceptors in inter‐ (mainly sexual recognition and social behavior‐kin recognition) or intra‐specific communication (mainly host selection) is discussed on the basis of behavioral and electrophysiological investigations performed on other parasitoid species belonging to the same family. Other sensilla with morphology that is not consistent with that of chemoreceptors are represented by grooved pegs, coeloconic pegs, trichoid sensilla. Such detailed ultrastructural investigation of the flagellar chemoreceptors of S. cereicollis, clarifying the number of chemosensory neurons innervating the different sensilla, is crucial for further electrophysiological investigations on this important species. Research Highlights: Evident sexual dimorphism concerning antennae length, type, number, and distribution of chemosensilla.Long sensilla basiconica (LSB) present only in females could play a role in host location and/or maternal care.Multiporous sensilla chaetica (MSC), significantly longer and mostly represented in males, could play a role in the perception of sexual pheromones.Detailed ultrastructural study is crucial for electrophysiological investigations on this important species. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Methodology Results Conclusions Fortunately, the majority of COVID‐19 patients recover from olfactory dysfunction (OD) within the first couple of weeks. However, from approximately 5% up to 20% continue to suffer from OD even more than 1 year after the onset. Nonetheless, factors associated with long‐lasting OD are hardly known. The aim of this study was to identify favourable and disadvantageous markers of persisting OD in COVID‐19 patients.Sixty‐six patients (46 female; mean age: 39.9 years) that suffer from OD longer than 6 months due to laboratory‐confirmed SARS‐CoV‐2 infection have participated in this longitudinal study. Participants completed comprehensive psychophysical chemosensory tests (i.e., Sniffin' Sticks = TDI) and questionnaires twice at our department—on average 219 ± 80 (T‐1) and 489 ± 89 (T‐2) days after the onset of symptoms, respectively. Olfactory recovery rates were associated with demographic factors and questionnaires using linear regression analysis.Patients below 40 years of age improved better (TDI: 4.1 ± 4.3 vs. 0.7 ± 5.8; p = 0.008) and achieved statistically significant higher scores (TDI: 31.5 ± 4.0 vs. 27.3 ± 6.7; p = 0.033) regarding psychophysical chemosensory tests. Furthermore, linear regression analysis revealed that parosmia was associated with worse orthonasal smell function (T‐1: β = −0.346, p = 0.004; T‐2: β = −0.384, p = 0.001), especially concerning identification subtest (T‐1: β = −0.395, p = 0.001; T‐2: β = −0.398, p < 0.001). Moreover, increasing parosmia between T‐1and T‐2 led to worse orthonasal olfactory function (β = −0.294, p = 0.016).Older age and parosmia seem to be unfavourable factors of persisting OD in COVID‐19 patients. [ABSTRACT FROM AUTHOR]

Background: MK-801 is a drug widely used in preclinical studies to model schizophrenia in animals. Its distinctive feature is the ability to mimic pathological changes in social interactions. Unlike humans, rodents rely heavily on their sense of smell for social interaction. Since, as previously demonstrated, it also impairs neurogenesis, we set out to determine whether olfactory impairment is associated with chronic administration of the drug. Methods: The mice were divided into two groups, of which one was administered the drug for 3 weeks, and the other only once. Olfaction and social transfer of food preferences were tested after the drug administration period. At the end of the experiment, an immunofluorescence study was performed to determine differences in neurogenesis in the olfactory bulbs. Results: An olfactory deficit was observed in animals that received the drug for 3 weeks. These changes were also accompanied by an abnormal lack of food preference in the social transmission test. As a result of a morphological study, a pronounced decrease in the number of new neurons was found in the olfactory bulbs of the animals that had received the drug. Conclusion: Our results indicate that at least some of the impairments in social behavior of the animals exposed to NMDA receptor antagonists are likely caused by changes in the sense of smell. These changes are associated with disruptions of neurogenesis. [ABSTRACT FROM AUTHOR]

Background: Child food neophobia, i.e., rejection or avoidance of novel foods at a young age, is a prevalent nutrition problem that affects the quality of children's diet and impedes the development of healthy food preferences. Sensory sensitivity can relate to the degree of food neophobia, but previous studies rarely focused on the olfactory component of this problem in children. Objective: We aimed to thoroughly examine the relationship between various aspects of olfactory sensitivity and food neophobia in children. Methods: 246 children aged between three and nine years took part in a food neophobia assessment as well as in a comprehensive, psychophysical olfactory testing. Results: We found that certain smell perception aspects such as lower odor liking, poorer odor identification ability as well as lower sensitivity to an unknown non-food odor all significantly predicted higher food neophobia in children. Among individual characteristics of either a child or a caregiver, only the child's age significantly and positively predicted food neophobia. The exploratory model looking into the role of family environment factors predicting self-reported food neophobia in children revealed that food neophobia was associated with lower control given to a child in this child's feeding process, as well as with a more frequent use of food as a reward in feeding. Conclusions: We suggest that suppressed olfactory perception and performance can play a unique role in child nutritional difficulties. The study inspires further considerations of olfaction-engaging interventions to counteract food-neophobia in children. [ABSTRACT FROM AUTHOR]

Most catarrhine primates are considered to be strongly visually oriented, obtaining information about conspecifics and their environment from a diversity of visual cues. Other sensory modalities may provide information that is redundant and/or complimentary to visual cues. When cues from multiple sensory modalities are available, these may reinforce or suppress each other, as shown in several taxa ranging from insects to humans. Here, we tested how the presence and ambiguity of visual information affect the use of olfactory cues when exploring food and non-food items in semi-free-ranging Barbary macaques at Affenberg Salem, Germany. We presented monkeys with pipes containing food (peanuts, popcorn), non-food (stones, feces), or no items in transparent or opaque containers and assessed whether animals looked, sniffed, and/or grabbed into the pipes depending on the visibility of the contents (experiment 1). Visual information had no robust effect on sniffing probability, but monkeys were more likely to sniff before any other form of inspection if the can was opaque than if it was transparent. Both visual and olfactory information affected, whether or not monkeys attempted to retrieve the items from the pipes, whereby monkeys showed an overall decrease in the propensity to grab after sniffing. Furthermore, we manipulated the visual appearance of familiar food items (popcorn) with food colorant (experiment 2), which resulted in substantially increased olfactory inspections compared to unmanipulated popcorn. Taken together, reliance on the olfactory sense was modulated by the available visual information, emphasizing the interplay between different sensory modalities for obtaining information about the environment. [ABSTRACT FROM AUTHOR]

Taste and smell disorders can worsen the nutritional status of patients receiving chemotherapy and potentially affect drug treatment. However, there is limited knowledge on antineoplastic agents that induce taste and smell disorders. Therefore, we used the U.S. Food and Drug Administration Adverse Event Reporting System database to analyze the characteristics of patients and antineoplastic agents in relation to taste and smell disorders. No gender differences related to the onset of taste and smell disorders were found, whereas older age was identified as a possible risk factor. Among the antineoplastic agent classes, protein kinase inhibitors appeared to be particularly likely to induce taste and smell disorders. According to the cluster and principal component analyses, antineoplastic agents were deemed to induce taste or smell disorders. In addition, antineoplastic agents that decreased or changed these sensations could be classified. These findings might be useful in selecting drugs for patients experiencing similar side effects. [ABSTRACT FROM AUTHOR]

The northern bark beetle, Ips duplicatus, is an emerging economic pest, reportedly infesting various species of spruce (Picea spp.), pine (Pinus spp.), and larch (Larix spp.) in Central Europe. Recent climate changes and inconsistent forest management practices have led to the rapid spread of this species, leaving the current monitoring strategies inefficient. As understanding the molecular components of pheromone detection is key to developing novel control strategies, we generated antennal transcriptomes from males and females of this species and annotated the chemosensory proteins. We identified putative candidates for 69 odorant receptors (ORs), 50 ionotropic receptors (IRs), 25 gustatory receptors (GRs), 27 odorant-binding proteins (OBPs), including a tetramer-OBP, 9 chemosensory proteins (CSPs), and 6 sensory neuron membrane proteins (SNMPs). However, no sex-specific chemosensory genes were detected. The phylogenetic analysis revealed conserved orthology in bark beetle chemosensory proteins, especially with a major forest pest and co-habitant, Ips typographus. Recent large-scale functional studies in I. typographus chemoreceptors add greater significance to the orthologous sequences reported here. Nevertheless, identifying chemosensory genes in I. duplicatus is valuable to understanding the chemosensory system and its evolution in bark beetles (Coleoptera) and, generally, insects. [ABSTRACT FROM AUTHOR]

Although olfaction is well known to guide animal behavior, the neural circuits underlying the motor responses elicited by olfactory inputs are poorly understood. In the sea lamprey, anatomical evidence shows that olfactory inputs project to the posterior tuberculum (PT), a structure containing dopaminergic (DA) neurons homologous to the mammalian ventral tegmental area and the substantia nigra pars compacta. Olfactory inputs travel directly from the medial olfactory bulb (medOB) or indirectly through the main olfactory bulb and the lateral pallium (LPal). Here, we characterized the transmission of olfactory inputs to the PT in the sea lamprey, Petromyzon marinus. Abundant projections from the medOB were observed close to DA neurons of the PT. Moreover, electrophysiological experiments revealed that PT neurons are activated by both the medOB and LPal, and calcium imaging indicated that the olfactory signal is then relayed to the mesencephalic locomotor region to initiate locomotion. In semi-intact preparations, stimulation of the medOB and LPal induced locomotion that was tightly associated with neural activity in the PT. Moreover, PT neurons were active throughout spontaneously occurring locomotor bouts. Altogether, our observations suggest that the medOB and LPal convey olfactory inputs to DA neurons of the PT, which in turn activate the brainstem motor command system to elicit locomotion. [ABSTRACT FROM AUTHOR]

Background: Hyposmia in Parkinson's disease (PD) had been studied before but had not been detailed by its temporal progression. This study observed how each olfactory subtype evolved in terms of motor symptoms, cardiac sympathetic innervation, and cognition. Methods: Two hundred and three early PD patients were classified as normosmia, hyposmia-converter (hypo-converter), and hyposmia. Their presynaptic monoamine availability at the time of diagnosis was assessed by positron emission tomography imaging using 18F-N-(3-fluoropropyl)-2beta-carbon ethoxy-3beta-(4-iodophenyl) nortropane and compared across the subtypes. Motor symptoms were evaluated in all patients, cardiac denervation was examined in 183 patients, and cognition in 195 patients were assessed using a neuropsychological battery. The domains were re-assessed 2–4 times, and the longitudinal data were analyzed to discern the natural course of each subtype. Results: Twenty-nine (14.3%) patients belonged to the normosmia group, 34 (16.7%) to the hypo-converter group, and the rest to the hyposmia (69.0%) group. 85.7% of the total population became hyposmic during an average 3 years of follow-up. The baseline motor symptoms, cardiac denervation, and cognition were comparable across the olfactory subtypes. Across the subtypes, a decline in the presynaptic monoamine densities of the caudate, especially the ventral-anterior subdivisions, correlated inversely with olfaction dysfunction. Over time, motor and cardiac denervation burdens worsened regardless of olfactory subtypes, but hypo-converters experienced faster cognitive deterioration than the other two groups. Conclusions: The results suggest that the olfactory subtypes have differential significance along the disease course, which might reflect the involvement of different neuro-biochemical circuitries. [ABSTRACT FROM AUTHOR]

Parkinson's disease displays clinical heterogeneity, presenting with motor and non-motor symptoms. Heterogeneous phenotypes, named brain-first and body-first, may reflect distinct α-synuclein pathology starting either in the central nervous system or in the periphery. The immune system plays a prominent role in the central and peripheral pathology, with misfolded α-synuclein being placed at the intersection between neurodegeneration and inflammation. Here, we characterized the inflammatory profile and immune-phenotype of peripheral blood mononuclear cells (PBMCs) from Parkinson's disease patients upon stimulation with α-synuclein monomer or oligomer, and investigated relationships of immune parameters with clinical scores of motor and non-motor symptoms. Freshly isolated PBMCs from 21 Parkinson's disease patients and 18 healthy subjects were exposed in vitro to α-synuclein species. Cytokine/chemokine release was measured in the culture supernatant by Multiplex Elisa. The immune-phenotype was studied by FACS-flow cytometry. Correlation analysis was computed between immune parameters and parkinsonian motor and non-motor scales. We found that Parkinson's disease patients exhibited a dysregulated PBMC-cytokine profile, which remained unaltered after exposure to α-synuclein species and correlated with both motor and non-motor severity, with a strong correlation observed with olfactory impairment. Exposure of PBMCs from healthy controls to α-synuclein monomer/oligomer increased the cytokine/chemokine release up to patient's values. Moreover, the PBMCs immune phenotype differed between patients and controls and revealed a prominent association of the Mos profile with olfactory impairment, and of NK profile with constipation. Results suggest that a deranged PBMC-immune profile may reflect distinct clinical subtypes and would fit with the recent classification of Parkinson's disease into peripheral-first versus brain-first phenotype. [ABSTRACT FROM AUTHOR]

Background: Sensory disability in older adults is associated with increased rates of depressive symptoms and loneliness. Here, we examined the impact of hearing, vision, and olfaction disability on mental health outcomes in older US adults. Methods: We studied respondents from the first three rounds (2005/6, 2010/11, and 2015/16) of the National Social Life, Health and Aging Project, a nationally representative, longitudinal study of older US adults. Sensory function was assessed by structured interviewer ratings (hearing and vision) and objective assessment (olfaction). Cox proportional hazards models and one degree of freedom tests for trend were utilized to analyze the relationships between sensory disability and self‐rated mental health, frequent depressive symptoms, frequent perceived stress, frequent anxiety symptoms, and frequent loneliness symptoms over time, adjusting for demographics, health behaviors, comorbidities, and cognitive function. Results: We analyzed data from 3940 respondents over 10 years of follow‐up. A greater number of sensory disabilities was associated with greater hazard of low self‐rated mental health, frequent depressive symptoms, frequent perceived stress, and frequent loneliness symptoms over time (p ≤ 0.003, all). After adjusting for covariates, older adults with a greater number of sensory disabilities had greater hazard of low self‐rated mental health (HR = 1.22, CI = [1.08, 1.38], p = 0.002) and loneliness symptoms (HR = 1.13, CI = [1.05, 1.22], p = 0.003) over time in our tests for trend. In our Cox proportional hazards model, older adults with vision disability had greater hazard of low self‐rated mental health (HR = 1.34, 95% CI = [1.05, 1.72], p = 0.02) and loneliness symptoms (HR = 1.21, CI = [1.04, 1.41], p = 0.01). Conclusions: Older US adults with greater numbers of sensory disabilities face worse subsequent mental health. Future longitudinal studies dissecting the relationship of all five classical senses will be helpful in further understanding how improving sensory function might improve mental health in older adults. [ABSTRACT FROM AUTHOR]

Predator–prey dynamics have led to a strong selection of prey's ability to detect and respond to information about the risk environment. Further, intrinsic factors, such as sex, may cause prey to perceive and respond to information differently. Chemical alarm cues from injured conspecifics are a classic example of how prey have evolved to use publicly available information to shape their behavior and enhance fitness, yet sex‐specific alarm reactions are rarely considered. The purpose of our study was to compare how males and females respond to conspecific chemical alarm cues in the livebearing fish species, Brachyrhaphis rhabdophora. Furthermore, we tested males and females from populations with a high‐ or low‐predation environment. Brachyrhaphis rhabdophora showed strong alarm reactions, but contrary to our predictions, showed limited variation due to sex or predation environment. We found that males and females from both populations displayed lower activity levels and increased their swimming depth when exposed to an alarm cue, despite variable and consistent baseline behaviors among individuals. These data further contribute to our understanding of what factors shape the evolution of behavioral responses to chemical alarm cues in fishes. [ABSTRACT FROM AUTHOR]

Background: Olfactory dysfunction (OD) affects many survivors of COVID‐19. Prior studies have investigated the use of platelet‐rich plasma (PRP) injections for OD. We describe the first randomized controlled trial investigating topical PRP for OD treatment and contribute to existing literature illustrating PRP as an emerging therapeutic. Methods: This is a single‐blinded, randomized controlled trial conducted from July 2022 to December 2023. Adult patients with OD ≥6 months secondary to COVID‐19 with Brief Smell Identification Test (BSIT) scores of ≤8/12 or SCENTinel odor intensity of ≤40/100 were included. Patients were randomized to three, monthly PRP or placebo‐impregnated Surgifoam treatments into bilateral olfactory clefts. The BSIT, SCENTinel, and Questionnaire of Olfactory Disorders—Negative Statements (QOD‐NS) were completed monthly through month 12. Results: Of 104 patients screened, 83 participated. No significant differences in age, OD duration, BSIT, SCENTinel, or QOD‐NS scores were found between PRP (n = 42) and placebo (n = 41) patients at baseline. PRP patients experienced a statistically significant increase in BSIT scores from baseline at months 5‒9, 11, and 12, while placebo patients did not (p < 0.05). However, total BSIT scores were similar between the two groups throughout the study. Neither the SCENTinel odor intensity scores nor the change from baseline were significantly different between the treatment groups. At month 12, PRP patients experienced minor improvement in OD‐related quality‐of‐life compared with placebo. Conclusions: This study is the first to describe topical PRP as a safe, experimental treatment for OD in humans. PRP may impact odor identification in post‐COVID‐19 OD patients, although the lack of difference in total BSIT scores highlights the need for further study. [ABSTRACT FROM AUTHOR]

Background: Diagnosing parosmia is a challenge. The present study aimed to explore the distinctions between hyposmic patients with and without parosmia utilizing electroencephalography‐derived olfactory event‐related potentials (ERP). Methods: Forty‐four patients with hyposmia were enrolled and divided into a group with parosmia (n = 23, mean age ± standard deviation = 48 ± 14 years, seven men) and a group without parosmia (n = 21, age = 52 ± 12 years, seven men) based on the clinical interview. Additionally, 21 healthy controls (mean age = 45 ± 14 years, six men) were included. Various measurements were obtained, including the Sniffin' Stick test, threshold tests for the odorants furfural mercaptan and 2,6‐nonadienal, a modified Sniffin' Stick parosmia test, and well‐being ratings. Chemosensory ERPs were recorded separately for each nostril using high‐precision, computer‐controlled air‐dilution olfactometry. Results: Patients with parosmia had a decreased olfactory function similar to that observed in patients with hyposmia, although the odor sensitivity of patients with severe parosmia remained relatively unaffected. Patients with parosmia reported a decrease in well‐being compared to controls. The severity of parosmia was positively correlated with odor sensitivity. Furthermore, patients with severe parosmia exhibited faster responses to unpleasant odors than patients without parosmia. Conclusion: Overall, the present findings support the idea that parosmia predominantly occurs during olfactory recovery, significantly disturbing patients and warranting the development of effective treatments. Notably, the relatively faster responses of hyposmic patients with severe parosmia suggest that the generation of distorted olfactory responses may involve early stages of the processing of olfactory information. [ABSTRACT FROM AUTHOR]

Background: Although allergic rhinitis (AR) can negatively impact the ability to smell, the degree to which this occurs is not clear and prevalence estimates vary among studies. This study had 4 main objectives: (1) To estimate the prevalence and the degree of olfactory dysfunction in AR patients; (2) To compare olfactory perception between AR patients with different persistence and severity of symptoms and determine if olfactory testing may aid in differentiating among Allergic Rhinitis and its Impact on Asthma (ARIA) groups; (3) To determine whether allergic reactions to different allergens differentially impact olfactory function, and (4) Verify possible changes in the olfactory epithelium (OE) caused by AR. Methods: One hundred thirty-three patients with AR and one hundred controls were tested. The main outcome was the score in University of Pennsylvania Smell Identification Test (UPSIT®). The OE was examined using immunofluorescence markers for neuronal activity, apoptosis, oxidative stress, signal transduction, eosinophils, and epithelial thickness. Results: Prevalence of olfactory dysfunction in the AR patients was higher (AR: 42.9% vs controls: 9%, P <.001). No difference was found either between intermittent and persistent disease cases (P =.58) or between cases with mild and those with moderate/severe symptomatology (P =.33). Lower olfactory capacity was not associated with the reaction to more (P =.48) or diverse types of allergens (P s >.05). Although not significant, patients with AR had a greater amount of eosinophilia and a lower amount of cAMP (cyclic adenosine monophosphate) in the OE. Conclusion: The study highlights a higher prevalence of olfactory dysfunction in AR patients compared to controls, but olfactory testing may not effectively differentiate AR severity or allergen sensitivities. Although trends suggest potential pathophysiological changes in the OE of AR patients, further research is needed to validate these findings. [ABSTRACT FROM AUTHOR]

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While previous studies have examined the influence of store atmospherics and social factors independently, limited research has investigated their synergistic impacts across cultures. In particular, the interactions between ambient scents, companionship influences, and cross-cultural shopping customs remain underexplored. Therefore, this study investigates how ambient scents influence retail shopping behaviors with a companion across cultures. Data were collected via surveys administered to customers in Polish and Indian shopping malls (N = 579), examining the impact of detected fragrances on time spent, money spent, purchase decisions, cognitive responses, and attitudes. Shopping with a companion in a scented environment has a more positive influence on time spent, money spent and impulse purchases in India than in Poland. There is no difference between these two cultures regarding cognitive responses to a scented retail environment, but there are significant differences for attitudinal responses and repurchase intentions. We found a positive association between the consumer rating of the shopping environment in terms of the ambient scent and the amount of money spent in India, but not in Poland. Theoretical and practical implications are discussed for optimizing atmospheric design according to cultural customs around shopping companionships. [ABSTRACT FROM AUTHOR]