Biology subjects

Sobel, N.

Publications and source records attributed to Sobel, N..

6 recordsLinked to original sources

bioRxiv2026

A cortical hierarchy of sensory representations from physical structure to idiosyncratic perception

Perception begins with the physical structure of the external world, yet each of us remaps that structure into an idiosyncratic ordering shaped by individual experience and makeup. To ask how these two orderings are reflected in the brain, we used fMRI in 47 participants to measure the representation of olfactory and visual stimuli chosen such that similarities among the odorants mirrored those among the images. Olfactory and visual cortices each reflected physical similarity more strongly than idiosyncratic perceptual similarity. By contrast, a whole-brain search for the alternative uncovered the left angular gyrus, which reflected idiosyncratic perceptual similarity in both olfaction and vision. Connectivity analysis depicted this region as a likely hub for such representation, and dynamic causal modeling supported this observation. These findings reveal a transition from stimulus-centered representations in modality-specific sensory cortex to a modality-general observer-centered representation in the angular gyrus, suggesting a potentially fundamental hierarchy in brain organization.

neuroscience↗

bioRxiv2025

High-Fidelity Tuning of Olfactory Mixture Distances in the Perceptual Space of Smell Through a Community Effort

A central goal in sensory science is to establish quantitative mappings between physical stimuli and perceptual responses. While such mappings are well characterized in vision and audition, they remain poorly defined in olfaction, limiting progress toward understanding the representations of smell. Predicting perceptual similarity between odor mixtures offers a promising route to formalize these relationships. To advance this effort, the DREAM (Dialogue for Reverse Engineering Assessment and Methods) Olfactory Mixtures Prediction Challenge assembled a curated, cross-study dataset describing the similarity of 507 mixture pairs and an unpublished test set of 46 mixture pairs. Teams competed to predict the perceptual similarity of mixture pairs, and then collaborated post-challenge to create an ensemble combining top-performing models that notably improves predictions over the existing state-of-the-art models. Moreover, ensemble model maintains high predictive accuracy in novel validation set. Our model provides a reproducible framework for neuroscientists, chemists, and engineers to compare odor mixtures and provides a foundation for future efforts towards better understanding the olfactory properties of mixtures.

neuroscience↗

bioRxiv2021

Sniffing Out New Friends: Similarity in Body-Odor Predicts the Quality of Same-Sex None-Romantic Dyadic Interactions

Most are familiar with the notion of socially "clicking" with someone, namely sensing an immediate bond that can lead to strong and often long-lasting friendships. The mechanisms underlying such rapid bonding remain unclear. Given that body-odor similarity is a critical cue for social interaction in non-human mammals, we tested the hypothesis that body-odor similarly contributes to bonding in same-sex non-romantic human dyads. We observed that objective ratings obtained with an electronic nose, and subjective ratings obtained from human smellers, converged to suggest that click-friends smell more similar to each other than random dyads. Remarkably, we then found that we could use the electronic nose to predict which strangers would later form better dyadic interactions. Thus, humans may literally sniff-out new friends based on similarities in body-odor.

neuroscience↗

bioRxiv2020

A Human Aggression Pheromone Elicits a Sexually Dimorphic Behavioral and Brain Response

Body-volatiles can effectively trigger or block conspecific aggression in terrestrial mammals. Here we tested whether hexadecanal (HEX), a human body-volatile implicated as a mammalian-wide social cue, impacts human aggression. Using validated behavioural paradigms, we observed a remarkable dissociation: sniffing HEX blocked aggression in men, but triggered aggression in women. Next, using functional brain imaging, we uncovered a pattern of brain activity mirroring behaviour: In both men and women, HEX increased activity in the left angular gyrus, an area implicated in perception of social cues. Hex then modulated functional connectivity between the angular gyrus and a brain network implicated in social appraisal (temporal pole) and aggressive execution (amygdala and orbitofrontal cortex) in a sex-dependent manner consistent with behaviour: increasing connectivity in men, but decreasing connectivity in women. These findings implicate sex-specific social chemosignaling at the mechanistic heart of human aggressive behaviour.

neuroscience↗

bioRxiv2020

Unexplained Repeated Pregnancy Loss is Associated with Altered Perceptual and Brain Responses to Men's Body-Odor

In the Bruce effect, pregnant mice remember the odor of the fathering male, and miscarry in response to the odor of a male stranger. Humans experience a high rate of unexplained spontaneous miscarriage. Could it be that a portion of these miscarriages reflect a Bruce-like effect? Given ethical constraints on a direct test, we instead probed for circumstantial evidence in women with repeated pregnancy loss (RPL). Consistent with a Bruce-like effect, women with RPL remembered the body-odor of their spouse, but controls could not. Also consistent with a Bruce-like effect, body-odor from a stranger man caused increased activity in the hypothalamus of women experiencing RPL, yet decreased activity in the hypothalamus of women controls. Finally, RPL was associated with reduced olfactory-bulb volume. Although not causal, these observations link RPL with an altered behavioral and brain response to mens body-odor, implicating the olfactory system in this poorly understood or managed condition.

physiology↗

bioRxiv2019

Local Targeted Memory Reactivation in Human Sleep

Memory consolidation can be promoted via Targeted Memory Reactivation (TMR) that re-presents training cues or context during sleep. Whether TMR acts locally or globally on cortical sleep oscillations remains unknown. Here we exploit the unique functional neuroanatomy of olfaction with its ipsilateral stimulus processing to perform local TMR in one brain hemisphere. Participants learned associations between words and locations in left or right visual fields with contextual odor throughout. During post-learning naps, odors were presented to one nostril throughout NREM sleep. We found improved memory for specific words processed in the cued hemisphere (ipsilateral to stimulated nostril). Unilateral odor cues locally modulated slow wave activity (SWA) such that regional SWA increase in the cued hemisphere negatively correlated with select memories for cued words. Moreover, local TMR improved slow wave-spindle coupling specifically in the cued hemisphere. Thus, TMR in human sleep transcends global action by selectively promoting specific memories associated with local sleep oscillations.

neuroscience↗