Biology subjects

Frasnelli, J.

Publications and source records attributed to Frasnelli, J..

5 recordsLinked to original sources

bioRxiv2026

Chemosensory ERP Suggest Peripherally Driven Olfactory-Trigeminal Interactions in Healthy Older Adults

The olfactory and intranasal trigeminal systems interact closely, influencing chemosensory perception, yet the mechanisms underlying their interaction remain poorly understood and have been studied mainly in young adults. We aimed to characterize olfactory-trigeminal interactions in aging by comparing electrophysiological and behavioral responses under ipsilateral and contralateral olfactory-trigeminal co-stimulation, to determine the relative contributions of peripheral and central mechanisms. Using chemosensory event-related potentials and a localization task, 44 healthy older adults (66.3 {+/-} 4.6 years; 29 women) were tested under four conditions: pure trigeminal (carbon dioxide; CO2), pure olfactory (2-phenylethanol; PEA), ipsilateral co-stimulation (PEA+CO2 in the same nostril), and contralateral co-stimulation (PEA+CO2 in opposite nostrils). Ipsilateral, but not contralateral olfactory-trigeminal co-stimulation, improved trigeminal localization performance and induced larger late positive component amplitudes. Together, these findings suggest that olfactory-trigeminal interactions are driven primarily by peripheral rather than central mechanisms. This study also provides normative CSERP data for healthy older adults.

neuroscience↗

bioRxiv2026

Bridging the gap between genome-wide association studies and network medicine with GNExT

MotivationA growing volume of large-scale genome-wide association study (GWAS) datasets offers unprecedented power to uncover the genetic determinants of complex traits, but existing web-based platforms for GWAS data exploration provide limited support for interpreting these findings within broader biological systems. Systems medicine is particularly well-suited to fill this gap, as its network-oriented view of molecular interactions enables the integration of genetic signals into coherent network modules, thereby opening opportunities for disease mechanism mining and drug repurposing. ResultsWe introduce GNExT (GWAS Network Exploration Tool), a web-based platform that significantly extends the scope of exploration of variant-level effects and significance beyond those provided by existing solutions. By including MAGMA and Drugst.One, GNExT allows its users to study genetic variants in the context of the latest systems medicine approaches, extending to the identification of potential drug repurposing candidates. Moreover, GNExT advances platform implementation well beyond the current state of the art by offering a highly standardized Nextflow pipeline for data import and preprocessing, allowing researchers to deploy their study results on a sophisticated web interface with minimal implementation overhead. We demonstrate the utility of GNExT using a genome-wide association meta-analysis of human olfactory identification, in which the framework translated isolated GWAS signals to potential pharmacological targets in human olfaction. Furthermore, the deployment of a GNExT instance on European-ancestry Pan-UK Biobank data demonstrates the frameworks scalability, resulting in a comprehensive large-scale resource encompassing thousands of traits and enabling new network medicine-based investigations. Availability and ImplementationThe complete GNExT ecosystem, including the Nextflow preprocessing pipeline, the backend service, and frontend interface, is publicly available on GitHub (https://github.com/dyhealthnet/gnext_nf_pipeline, https://github.com/dyhealthnet/gnext_platform). The public instances of the GNExT platform on olfaction and Pan-UKBB are available under https://olfaction.gnext.gm.eurac.edu and https://panukbb-eur.gnext.gm.eurac.edu.

bioinformatics↗

bioRxiv2025

Odor-evoked respiratory responses throughout development in sighted and blind mice

Congenital blindness affects olfactory function depending on developmental stage. However, when studying the ontogeny of olfactory abilities, not all behaviors are expressed at every age making the longitudinal comparisons difficult. Odor-evoked respiratory responses, which are unlearned and do not require complex motor coordination, may serve as sensitive measures of olfactory abilities throughout ontogeny. Using a non-invasive measure of respiration in an olfactory perceptual paradigm, we assessed odor-evoked respiratory responses in a model of congenital blindness at 3 ages, infant, juvenile and adult, in the same mice and in both males and females. We demonstrated the differential outcome of two respiratory parameters (i.e. frequency and amplitude) in a mouse model of congenital blindness. We showed that blind mice have similar olfactory abilities than sighted mice throughout ontogeny but display enhanced sniffing frequency and amplitude, starting at the juvenile age for the latter one, that may help them better explore their environment. We also demonstrated that respiratory frequency is a robust index of age and of olfactory detection, habituation and discrimination at all ages. On the other side, respiratory amplitude does not provide a proxy of olfactory performance at all ages, however, it does highlight differences between sexes and phenotypes associated with visual deprivation. To conclude, our data highlight that respiratory parameters can be used as a complementary approach to assess olfactory performance throughout development and provide an index of olfactory plasticity.

neuroscience↗

bioRxiv2023

Metabolic state modulates neural processing of odors in the human olfactory bulb

The olfactory and endocrine systems have recently been shown to reciprocally shape the homeostatic processes of energy intake. As demonstrated in animal models, the individuals metabolic state dynamically modulates how the olfactory bulb process odor stimuli using a range of endocrine signals. Here we aimed to determine whether the neural processing of odors in human olfactory bulb is modulated by metabolic state. Participants were exposed to food-associated odors, in separate sessions being hungry and sated, while neural responses from the olfactory bulb was obtained using electrobulbogram. We found significantly higher gamma power activity (51-100Hz) in the OBs response to odors during the Hunger compared to Sated condition. Specifically, EBG gamma power were elevated while hungry already at 100ms after odor onset, thereby suggesting intra-bulbar modulation according to metabolic state. These results demonstrate that, akin to other animal models, hunger state affects OB activity in humans. Moreover, we show that the EBG method has the potential to measure internal metabolic states and, as such, could be used to study specificities in olfactory processing of individuals suffering from pathologies such as obesity or anorexia.

neuroscience↗

bioRxiv2022

Behavioral Evidence for Enhanced Olfactory and Trigeminal Perception in Congenitally Deaf Individuals

Sensory deprivation, particularly hearing loss, is an excellent model to study neuroplasticity in the human brain and the adaptive behaviors that support the daily lives of deprived individuals. In adaptation to their hearing loss, deaf individuals rely on their other intact senses. Visual and tactile abilities are enhanced in deafness, but few studies have evaluated the olfactory function. This study aimed to compare the impact of congenital deafness on olfactory capacities using psychophysical tasks. Methodological issues raised in previous studies, such as homogeneous onset of deafness and cognitive function assessment, were considered. Eleven individuals with bilateral severe-to-profound deafness since birth were compared to 11 hearing non-signers similar in age (age range = 20-51 years old) and sex (7 women). The deaf subjects were assessed using various standardized neuropsychological tests to ascertain typical cognition. Olfactory functions were evaluated using the Sniffin Sticks battery test, which measures olfactory detection threshold, odor discrimination, and odor identification. Further, accuracy and response time were examined for the identification and localization of two odors to disentangle olfactory sensitivity from sensitivity in the trigeminal system. The Sniffin Sticks test demonstrated superior performances in the deaf participants to discriminate and identify odors. In line with this, they also showed higher sensitivity when both identifying and localizing odors. These findings suggest that congenital deafness is associated with superior performance in higher-level olfactory processing and increased sensitivity in the trigeminal system.

neuroscience↗