Comparison of trigeminal lateralization with differing stimulants.

Trigeminal-specific stimulants have been shown to activate different receptors preferentially and this likely accounts for variation in sensory perception. It is unclear whether trigeminal sensitivity is similar across different transient receptor potential (TRP) receptors or if dysfunction of different receptors results in differing patient symptoms. Therefore, a prospective cohort study was conducted, consisting of trigeminal lateralization testing with three different stimulants (eucalyptol, isothiocyanate, acetic acid), olfaction testing with Sniffin' Sticks, and measurement of various patient-reported outcome measures (PROMs). A total of 50 participants were enrolled across the olfactory spectrum. Mean TDI score was 27.1 ± 8.3 (range 7.0-39.5) with 38% normosmic and 62% dysosmic. Mean trigeminal lateralization scores out of 20 in the overall cohort were 16.18 (2.78) for eucalyptol, 14.94 (3.49) for mustard oil, and 15.28 (3.68) for vinegar. Eucalyptol showed a significant correlation with threshold scores of Sniffin' Sticks. A significant correlation was found between acetic acid and various PROMs. None of the lateralization scores of the trigeminal stimulants correlated to each other significantly and there was no correlation to age. The lack of correlation suggests that the measured sensitivity of one type of TRP receptor may not translate to similar sensitivity of the other receptors. Additional investigations with TRPV1 and TRPA1 agonists are needed to corroborate our findings.

Association of alcohol use with olfactory function among older adults.

BACKGROUND/PURPOSE: Olfactory dysfunction (OD) has been recognized as an early biomarker for neurodegenerative diseases. Identifying behaviors that increase the risk of OD is crucial for early recognition of neurogenerative diseases. Alcohol consumption can potentially impact olfaction through its neurotoxic effects. This study aims to examine the relationship between alcohol consumption and OD, using data from the National Social Life, Health, and Aging Project (NSHAP). METHODS: This cross-sectional study was conducted on data for 2757 adults from Round 1 of NSHAP. OD was defined as correctly identifying 0-3 odors in the 5-item Sniffin' Sticks test while normal olfactory function was defined as correctly identifying 4-5 odors. Multivariable logistic regression was utilized to examine the association between alcohol consumption and OD, controlling for age, race, and comorbidities. Analyses were weighted to account for the sampling design. RESULTS: OD was present in 23.1 % of adults. The average age among those with OD was 71.2 ± 7.8 years, compared to 66.9 ± 7.2 years in those with normal olfaction. In terms of alcohol consumption, 31.1 % of adults with OD were light-to-moderate drinkers and 7.7 % were heavy drinkers, compared to 35.6 % light-to-moderate and 7.7 % heavy drinkers in the normal olfaction group. After adjusting for age, gender, race, and education, neither light-to-moderate drinking (aOR: 0.99; 95 % CI: 0.76-1.29) nor heavy drinking (aOR: 1.24; 95 % CI: 0.83-1.85) were significantly associated with OD. CONCLUSION: Alcohol consumption was not associated with OD after controlling for covariates. While this study provides insight into the relationship between alcohol consumption and OD, further research is needed due to conflicting results in previous studies.

Pronounced Olfactory Habituation with Age.

OBJECTIVES: Olfactory habituation is a transient decrease in olfactory sensitivity caused by prolonged odor exposure, aiding in the discernment of new olfactory stimuli against the background. We explored the impact of subclinical olfactory impairment on odor habituation using age as a proxy. METHODS: Before the actual experiment, the individual olfactory threshold for the rose-like odorant phenylethyl alcohol (PEA) was assessed separately for the left and right nostril using the "Sniffin' Sticks" test, and ratings for odor intensity and pleasantness were collected. After applying a nasal clip continuously delivering PEA odor to one nostril for 10 min and 2 h, respectively, threshold, intensity, and pleasantness were reassessed immediately after clip removal. RESULTS: In the group of 80 participants (younger adults-mean age 27.7 ± 4.5 years; older adults-mean age 61.5 ± 4.7 years), olfactory thresholds were already significantly elevated after just 10 min, and this habituation was even more pronounced after 2 h. This effect could be observed bilaterally even though significantly more distinct on the exposed side. Older participants generally exhibited a more pronounced habituation on the exposed side after 2 h compared to the younger participants. CONCLUSION: The results indicate that older people experience more notable habituation after extended exposure to odors. This is most likely due to the compromised olfactory function in age. Although older and younger subjects scored in the normosmic range when tested with standardized olfactory tests, the stress on the system after exposure to an odor clearly revealed the lower functionality of the aging sense of smell. LEVEL OF EVIDENCE: 3 Laryngoscope, 2024.

Olfactory function in diabetes mellitus.

Diabetes mellitus (DM) is an increasingly common disease in both children and adults. In addition to neuronal and/or vascular disorders, it can cause chemosensory abnormalities including olfactory deterioration. The purpose of this article is to summarize current knowledge on olfactory function in DM, highlighting the impact of co-morbidities, especially obesity, thyroid dysfunction, chronic kidney disease and COVID-19 on olfactory outcomes. Research to date mostly shows that olfactory impairment is more common in people with diabetes than in the general population. In addition, the presence of concomitant diseases is a factor increasing olfactory impairment. Such a correlation was shown for type 1 diabetes, type 2 diabetes and gestational diabetes. At the same time, not only chronic diseases, but also DM in acute conditions such as COVID-19 leads to a higher prevalence of olfactory disorders during infection. Analyzing the existing literature, it is important to be aware of the limitations of published studies. These include the small number of patients studied, the lack of uniformity in the methods used to assess the sense of smell, frequently relying on rated olfactory function only, and the simultaneous analysis of patients with different types of diabetes, often without a clear indication of diabetes type. In addition, the number of available publications is small. Certainly, further research in this area is needed. From a practical point of view decreased olfactory performance may be an indicator for central neuropathy and an indication for assessing the patient's nutritional status, examining cognitive function, especially in older patients and performing additional diagnostic tests, such as checking thyroid function, because all those changes were correlated with smell deterioration.

Residues of chlorpyrifos in the environment induce resistance in Aedes albopictus by affecting its olfactory system and neurotoxicity.

Aedes albopictus, a virus-vector pest, is primarily controlled through the use of insecticides. In this study, we investigated the mechanisms of resistance in Ae. albopictus in terms of chlorpyrifos neurotoxicity to Ae. albopictus and its effects on the olfactory system. We assessed Ca2+-Mg2+-ATP levels, choline acetyltransferase (ChAT), Monoamine oxidase (MAO), odorant-binding proteins (OBPs), and olfactory receptor (OR7) gene expression in Ae. albopictus using various assays including Y-shaped tube experiments and DanioVision analysis to evaluate macromotor behavior. Our findings revealed that cumulative exposure to chlorpyrifos reduced the activity of neurotoxic Ca2+-Mg2+-ATPase and ChAT enzymes in Ae. albopictus to varying degrees, suppressed MAO-B enzyme expression, altered OBPs and OR7 expression patterns, as well as affected evasive response, physical mobility, and cumulative locomotor time under chlorpyrifos stress conditions for Ae. albopictus individuals. Consequently, these changes led to decreased feeding ability, reproductive capacity, and avoidance behavior towards natural enemies in Ae. albopictus populations exposed to chlorpyrifos stressors over time. To adapt to unfavorable living environments, Ae. albopictus may develop certain tolerance mechanisms against organophosphorus pesticides. This study provides valuable insights for guiding rational insecticide usage or dosage adjustments targeting the nervous system of Ae. albopictus.

Predictors of Subjective Olfactory Dysfunction and Sinonasal Quality-of-Life After Endoscopic Transsphenoidal Pituitary Surgery.

BACKGROUND: This is the largest study in North America investigating olfactory outcomes after pituitary surgery to date. OBJECTIVE: Characterize factors associated with subjective olfactory dysfunction (OD) and worsened sinonasal quality-of-life (QOL) after endoscopic TSA. METHODS: Patients undergoing primary TSA for secreting and non-secreting pituitary adenomas between 2017 and 2021 with pre- and post-operative SNOT-22 scores were included. Subjective OD was determined by the smell/taste dysfunction question on the SNOT-22 (smell-SNOT). RESULTS: 159 patients with pre- and post-operative SNOT-22 scores were included. Average total SNOT-22 scores worsened from pre-operative (16.91 ± 16.91) to POM1 (25.15 ± 20.83, P < .001), with no difference from pre-operative (16.40 ± 15.88) to POM6 (16.27 ± 17.92, P = .936) or pre-operative (13.63 ± 13.54) to POM12 (12.60 ± 16.45, P = .651). Average smell-SNOT scores worsened from pre-operative (0.40 ± 1.27) to POM1 (2.09 ± 2.01, P < .001), and pre-operative (0.46 ± 1.29) to POM6 (1.13 ± 2.45, P = .002), with no difference from pre-operative (0.40 ± 1.07) to POM12 (0.71 ± 1.32, P = .100). Female gender had a 0.9-point (95% CI 0.1 to 1.6) P = .021, increase in smell-SNOT at POM1, resolving by POM6 (0.1 [-0.9 to 1.1], P = .800) and POM12 (0.0 [-1.0 to 0.9], P = .942). Septoplasty with tunnel approach had a 1.1 [0.2 to 2.0] out of 5-point (P = .023) increase in smell-SNOT at POM1, resolving by POM6 (0.2 [-1.1 to 1.6], P = .764) and POM12 (0.4 [-0.9 to 1.6], P = .567). Female gender had a 9.5 (4.0 to 15.1)-point (P = .001) increase in SNOT-22 scores at POM1, resolving by POM6 (3.4 [-3.0 to 9.8], P = .292) and POM12 (6.4 [-5.4 to 18.2], P = .276). Intra-operative CSF leak had an 8.6 [2.1 to 15.1]-point (P = .009) increase in SNOT-22 scores at POM1, resolving by POM6 (5.4 [-1.7 to 12.5], P = .135), and POM12 (1.1 [-12.9 to 15.1], P = .873). CONCLUSION: Changes in subjective olfaction and sinonasal QOL after TSA may be associated with gender, operative approach, and intra-operative CSF leak, resolving 6-12 months post-operatively.

Disruption of Zfh3 abolishes mulberry-specific monophagy in silkworm larvae.

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.

A practical test for retronasal odor identification based on aromatized tablets.

BACKGROUND: Olfactory perceptions elicited by odors originating from within the body (retronasal olfaction) play a crucial role in well-being and are often disrupted in various medical conditions. However, the assessment of retronasal olfaction in research and the clinical practice is impeded by the lack of commercially available tests and limited standardization of existing testing materials. NEW METHOD: The novel ThreeT retronasal odor identification test employs 20 flavored tablets that deliver a standardized amount of odorous stimuli. The items represent common food- and non-food-related odors. RESULTS: The ThreeT test effectively distinguishes patients with olfactory dysfunction from healthy controls, achieving a specificity of 86% and sensitivity of 73%. Its scores remain stable for up to 3 months (r=.79). COMPARISON WITH EXISTING METHOD: ThreeT test exhibits a strong correlation with "Tasteless powders" measure of retronasal olfaction (r=.78) and classifies people into healthy and patient groups with similar accuracy. Test-retest stability of ThreeT is slightly higher than the stability of "Tasteless powders" (r=.79 vs r=.74). CONCLUSIONS: ThreeT is suitable for integration into scientific research and clinical practice to monitor retronasal odor identification abilities.

Scent Detection Threshold of Trained Dogs to Eucalyptus Hydrolat.

Dogs' (Canis lupus familiaris) sense of smell is based on a unique anatomy and physiology that enables them to find and differentiate low concentrations of odor molecules. This ability is exploited when dogs are trained as search, rescue, or medical detection dogs. We performed a three-part study to explore the scent detection threshold of 15 dogs to an in-house-made Eucalyptus hydrolat. Here, decreasing concentrations of the hydrolat were tested using a three-alternative forced-choice method until the first incorrect response, which defined the limit of scent detection for each tested dog. Quantitative proton nuclear magnetic resonance spectroscopy was used to identify and measure the contents of ten commercial Eucalyptus hydrolats, which are used in a dog scent training sport called "nose work". In this study, the dogs' limit of detection initially ranged from 1:104 to 1:1023 but narrowed down to 1:1017-1:1021 after a training period. The results show that, with training, dogs learn to discriminate decreasing concentrations of a target scent, and that dogs can discriminate Eucalyptus hydrolat at very low concentrations. We also detected different concentrations of eucalyptol and lower alcohols in the hydrolat products and highlight the importance of using an identical source of a scent in training a dog for participation in canine scent sport competitions and in olfactory research.

Localized Expression of Olfactory Receptor Genes in the Olfactory Organ of Common Minke Whales.

Baleen whales (Mysticeti) possess the necessary anatomical structures and genetic elements for olfaction. Nevertheless, the olfactory receptor gene (OR) repertoire has undergone substantial degeneration in the cetacean lineage following the divergence of the Artiodactyla and Cetacea. The functionality of highly degenerated mysticete ORs within their olfactory epithelium remains unknown. In this study, we extracted total RNA from the nasal mucosae of common minke whales (Balaenoptera acutorostrata) to investigate ORs' localized expression. All three sections of the mucosae examined in the nasal chamber displayed comparable histological structure. However, the posterior portion of the frontoturbinal region exhibited notably high OR expression. Neither the olfactory bulb nor the external skin exhibited the expression of these genes. Although this species possesses four intact non-class-2 ORs, all the ORs expressed in the nasal mucosae belong to class-2, implying the loss of aversion to specific odorants. These anatomical and genomic analyses suggest that ORs are still responsible for olfaction within the nasal region of baleen whales, enabling them to detect desirable scents such as prey and potential mating partners.

Transgenic line for characterizing GABA-receptor expression to study the neural basis of olfaction in the yellow-fever mosquito.

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 mosquito's 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.

Epigenetic programming of stochastic olfactory receptor choice.

The mammalian sense of smell relies upon a vast array of receptor proteins to detect odorant compounds present in the environment. The proper deployment of these receptor proteins in olfactory sensory neurons is orchestrated by a suite of epigenetic processes that remodel the olfactory genes in differentiating neuronal progenitors. The goal of this review is to elucidate the central role of gene regulatory processes acting in neuronal progenitors of olfactory sensory neurons that lead to a singular expression of an odorant receptor in mature olfactory sensory neurons. We begin by describing the principal features of odorant receptor gene expression in mature olfactory sensory neurons. Next, we delineate our current understanding of how these features emerge from multiple gene regulatory mechanisms acting in neuronal progenitors. Finally, we close by discussing the key gaps in our understanding of how these regulatory mechanisms work and how they interact with each other over the course of differentiation.

What do brain oscillations tell about the human sense of smell?

Brain activity may manifest itself as oscillations which are repetitive rhythms of neuronal firing. These local field potentials can be measured via intracranial electroencephalography (iEEG). This review focuses on iEEG used to map human brain structures involved in olfaction. After presenting the methodology of the review, a summary of the brain structures involved in olfaction is given, followed by a review of the literature on human olfactory oscillations in different contexts. A single case is provided as an illustration of the olfactory oscillations. Overall, the timing and sequence of oscillations found in the different structures of the olfactory system seem to play an important role for olfactory perception.

Neurobiology of Social Interactions Across Species Role of neuroestrogens in the regulation of social behaviors - From social recognition to mating.

In this mini-review, we summarize the brain distribution of aromatase, the enzyme catalyzing the synthesis of estrogens from androgens, and the mechanisms responsible for regulating estrogen production within the brain. Understanding this local synthesis of estrogens by neurons is pivotal as it profoundly influences various facets of social behavior. Neuroestrogen action spans from the initial processing of socially pertinent sensory cues to integrating this information with an individual's internal state, ultimately resulting in the manifestation of either pro-affiliative or - aggressive behaviors. We focus here in particular on aggressive and sexual behavior as the result of correct individual recognition of intruders and potential mates. The data summarized in this review clearly point out the crucial role of locally synthesized estrogens in facilitating rapid adaptation to the social environment in rodents and birds of both sexes. These observations not only shed light on the evolutionary significance but also indicate the potential implications of these findings in the realm of human health, suggesting a compelling avenue for further investigation.

Evaluating olfactory function and quality of life in patients with traumatic brain injury.

KEY POINTS: Patients with traumatic brain injury (TBI) had worse olfactory quality of life (QoL) and Sino-Nasal Outcome Test-22 scores compared to a normal cohort. A worse olfactory QoL correlated with concussion symptom burden. Olfactory dysfunction among TBI patients should be addressed to improve overall outcomes.

The relationship between survey-based subjective olfactory awareness and objective olfactory function.

KEY POINTS: Correlation between symptom-based surveys and objective olfactory testing is variable. For diagnosis and symptom monitoring, surveys should correlate with objective testing. The Odor Awareness Scale (OAS) and Affective Importance of Odor Scale (AIO) showed significant but moderate positive correlations with University of Pennsylvania Scent Identification Test (UPSIT) score.

Circadian rhythm mechanism in the suprachiasmatic nucleus and its relation to the olfactory system.

Animals need sleep, and the suprachiasmatic nucleus, the center of the circadian rhythm, plays an important role in determining the timing of sleep. The main input to the suprachiasmatic nucleus is the retinohypothalamic tract, with additional inputs from the intergeniculate leaflet pathway, the serotonergic afferent from the raphe, and other hypothalamic regions. Within the suprachiasmatic nucleus, two of the major subtypes are vasoactive intestinal polypeptide (VIP)-positive neurons and arginine-vasopressin (AVP)-positive neurons. VIP neurons are important for light entrainment and synchronization of suprachiasmatic nucleus neurons, whereas AVP neurons are important for circadian period determination. Output targets of the suprachiasmatic nucleus include the hypothalamus (subparaventricular zone, paraventricular hypothalamic nucleus, preoptic area, and medial hypothalamus), the thalamus (paraventricular thalamic nuclei), and lateral septum. The suprachiasmatic nucleus also sends information through several brain regions to the pineal gland. The olfactory bulb is thought to be able to generate a circadian rhythm without the suprachiasmatic nucleus. Some reports indicate that circadian rhythms of the olfactory bulb and olfactory cortex exist in the absence of the suprachiasmatic nucleus, but another report claims the influence of the suprachiasmatic nucleus. The regulation of circadian rhythms by sensory inputs other than light stimuli, including olfaction, has not been well studied and further progress is expected.

Olfactory function after mild traumatic brain injury in children-a longitudinal case control study.

The prevalence of posttraumatic olfactory dysfunction in children after mild traumatic brain injury ranges from 3 to 58%, with potential factors influencing this variation, including traumatic brain injury severity and assessment methods. This prospective longitudinal study examines the association between mild traumatic brain injury and olfactory dysfunction in children. Seventy-five pediatric patients with mild traumatic brain injury and an age-matched healthy control group were enrolled. Olfactory function was assessed using the Sniffin' Sticks battery, which focuses on olfactory threshold and odor identification. The study found that children with mild traumatic brain injury had impaired olfactory function compared with healthy controls, particularly in olfactory threshold scores. The prevalence of olfactory dysfunction in the patient group was 33% and persisted for 1 yr. No significant association was found between traumatic brain injury symptoms (e.g. amnesia, loss of consciousness) and olfactory dysfunction. The study highlights the importance of assessing olfactory function in children after mild traumatic brain injury, given its potential impact on daily life. Although most olfactory dysfunction appears transient, long-term follow-up is essential to fully understand the recovery process. The findings add valuable insights to the limited literature on this topic and urge the inclusion of olfactory assessments in the management of pediatric mild traumatic brain injury.

Dogs' ability to detect an inflammatory immune response in cattle via olfaction.

Introduction: Canine olfaction is a potential means for detection of respiratory disease in beef cattle. In a prior study, two dogs were trained to discriminate between nasal swabs from healthy cattle and cattle that developed Bovine Respiratory Disease. Dogs had some ability to identify samples from BRD-affected cattle, but results were ambiguous. The purpose of this study was to evaluate more dogs using better-controlled training and testing procedures. Methods: Nasal and saliva swabs were collected from 96 cattle before and after administering a vaccine to induce an inflammatory immune response. Samples were stored at -80°C for up to 11 months before use, and samples from animals with an elevated body temperature at baseline were omitted. An automated olfactometer apparatus was constructed to improve blinding procedures and reduce opportunities for odor contamination. Four dogs were trained to distinguish between swabs from healthy and sickness-model cattle, including the two dogs from the previous study ("Runnels" and "Cheaps") and two inexperienced dogs ("Molokai" and "Amy"). During a seven-month training period, dogs were exposed to samples from 28 animals. Dogs were tested on 59 sets of unfamiliar samples. Results: Performance varied among dogs (χ2 = 10.48, p = 0.02). Molokai's performance was above chance (0.73 ± 0.06, p = 0.0006), while Amy (0.44 ± 0.06, p = 0.43), Cheaps (0.53 ± 0.07, p = 0.79), and Runnels (0.56 ± 0.06, p = 0.43) did not respond correctly at a rate different from chance. Accuracy did not differ between nasal swabs (0.63 ± 0.08) and saliva swabs (0.53 ± 0.08, χ2 = 0.81, p = 0.37). Discussion: The results of this study indicate that canine olfaction may be an effective means of detecting illness in beef cattle. However, individual dogs' aptitude for this detection task varies.

Semantic context-dependent neural representations of odors in the human piriform cortex revealed by 7T MRI.

Olfactory perception depends not only on olfactory inputs but also on semantic context. Although multi-voxel activity patterns of the piriform cortex, a part of the primary olfactory cortex, have been shown to represent odor perception, it remains unclear whether semantic contexts modulate odor representation in this region. Here, we investigated whether multi-voxel activity patterns in the piriform cortex change when semantic context modulates odor perception and, if so, whether the modulated areas communicate with brain regions involved in semantic and memory processing beyond the piriform cortex. We also explored regional differences within the piriform cortex, which are influenced by olfactory input and semantic context. We used 2 × 2 combinations of word labels and odorants that were perceived as congruent and measured piriform activity with a 1-mm isotropic resolution using 7T MRI. We found that identical odorants labeled with different words were perceived differently. This labeling effect was observed in multi-voxel activity patterns in the piriform cortex, as the searchlight decoding analysis distinguished identical odors with different labels for half of the examined stimulus pairs. Significant functional connectivity was observed between parts of the piriform cortex that were modulated by labels and regions associated with semantic and memory processing. While the piriform multi-voxel patterns evoked by different olfactory inputs were also distinguishable, the decoding accuracy was significant for only one stimulus pair, preventing definitive conclusions regarding the locational differences between areas influenced by word labels and olfactory inputs. These results suggest that multi-voxel patterns of piriform activity can be modulated by semantic context, possibly due to communication between the piriform cortex and the semantic and memory regions.