DOI: 10.57760/sciencedb.02598
title: Decomposition of an odorant in olfactory perception and neural representation
title: Decomposition of an odorant in olfactory perception and neural representation

description: AbstractMolecules –– the elementary units of substances –– are commonly considered the units of processing in olfaction, giving rise to undifferentiated odor objects invariant to environmental variations. By selectively perturbing the processing of chemical substructures with adaptation, “the psychologist's microelectrode”, the current study provides psychophysical and neuroimaging evidence (n = 350) that argues otherwise. We show that two perceptually distinct odorants sharing part of their structural features become significantly less discernable following adaptation to a third odorant containing their non-shared structural features, in manners independent of olfactory intensity, valence, quality, or general olfactory adaptation. The effect is accompanied by reorganizations of ensemble activity patterns in the posterior piriform cortex that parallel subjective odor quality changes, in addition to substructure-based neural adaptations in the anterior piriform cortex and amygdala. These findings demonstrate that central representations of odor quality and the perceptual outcome embed submolecular structural information and are malleable by recent olfactory encounters.Usage NotesThe ‘preprocessed images.zip’ file stores fMRI data that were preprocessed using the standard procedure in SPM12(http://www.fil.ion.ucl.ac.uk/spm). EPI images were corrected for slice timing differences and geometric distortion due to susceptibility artefacts (using participants’ field maps), spatially realigned to the first volume of the first session (first baseline run on Day 1) and unwarped to reduce movement related variance, and smoothed by a Gaussian kernel with 6-mm full width at half maximum to increase signal-to-noise ratio.The ‘clean data.zip’ file stores fMRI data that the no interest effects (motion regressors and low-frequency drift) were subtracted out from the preprocessed functional data with AFNI programs 3dDeconvolve and 3dSynthesize (https://afni.nimh.nih.gov/).The ‘OdorDetectionTask.zip’ file stores the task scripts used in the fMRI scanner.The ‘ROI.zip’ file stores the masks of region of interest used in analysis.The ‘Results.zip’ file stores all results.
description: AbstractMolecules –– the elementary units of substances –– are commonly considered the units of processing in olfaction, giving rise to undifferentiated odor objects invariant to environmental variations. By selectively perturbing the processing of chemical substructures with adaptation, “the psychologist's microelectrode”, the current study provides psychophysical and neuroimaging evidence (n = 350) that argues otherwise. We show that two perceptually distinct odorants sharing part of their structural features become significantly less discernable following adaptation to a third odorant containing their non-shared structural features, in manners independent of olfactory intensity, valence, quality, or general olfactory adaptation. The effect is accompanied by reorganizations of ensemble activity patterns in the posterior piriform cortex that parallel subjective odor quality changes, in addition to substructure-based neural adaptations in the anterior piriform cortex and amygdala. These findings demonstrate that central representations of odor quality and the perceptual outcome embed submolecular structural information and are malleable by recent olfactory encounters.Usage NotesThe ‘preprocessed images.zip’ file stores fMRI data that were preprocessed using the standard procedure in SPM12(http://www.fil.ion.ucl.ac.uk/spm). EPI images were corrected for slice timing differences and geometric distortion due to susceptibility artefacts (using participants’ field maps), spatially realigned to the first volume of the first session (first baseline run on Day 1) and unwarped to reduce movement related variance, and smoothed by a Gaussian kernel with 6-mm full width at half maximum to increase signal-to-noise ratio.The ‘clean data.zip’ file stores fMRI data that the no interest effects (motion regressors and low-frequency drift) were subtracted out from the preprocessed functional data with AFNI programs 3dDeconvolve and 3dSynthesize (https://afni.nimh.nih.gov/).The ‘OdorDetectionTask.zip’ file stores the task scripts used in the fMRI scanner.The ‘ROI.zip’ file stores the masks of region of interest used in analysis.The ‘Results.zip’ file stores all results.