Internal action models (IAMs) are brain templates for sensory-motor coordination underlying diverse behaviors. An emerging theory suggests that impaired IAMs are a common theme in autism spectrum disorder (ASD). However, whether impaired IAMs occur across sensory systems and how they relate to the major phenotype of ASD, namely impaired social communication, remains unclear. Olfaction relies on an IAM known as the sniff response, where sniff magnitude is automatically modulated to account for odor valence. To test the failed IAM theory in olfaction, we precisely measured the non-verbal non-task-dependent sniff response concurrent with pleasant and unpleasant odors in 36 children--18 with ASD and 18 matched typically developing (TD) controls. We found that whereas TD children generated a typical adult-like sniff response within 305 ms of odor onset, ASD children had a profoundly altered sniff response, sniffing equally regardless of odor valance. This difference persisted despite equal reported odor perception and allowed for 81% correct ASD classification based on the sniff response alone (binomial, p < 0.001). Moreover, increasingly aberrant sniffing was associated with increasingly severe ASD (r = -0.75, p < 0.001), specifically with social (r = -0.72, p < 0.001), but not motor (r < -0.38, p > 0.18), impairment. These results uncover a novel ASD marker implying a mechanistic link between the underpinnings of olfaction and ASD and directly linking an impaired IAM with impaired social abilities.
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http://dx.doi.org/10.1016/j.cub.2015.05.048 | DOI Listing |
J Anim Sci
January 2024
Global Forensic and Justice Center and Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA 33199.
Physiol Behav
March 2025
Smell & Taste Center, Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. Electronic address:
The mathematical relationship between the ability to detect an odorant and its concentration appears for some odorants to be non-monotonic, with reversals ("notches") in performance appearing at points along the psychometric function. Like visual adaptation curves that reflect the differential sensitivities of cones and rods, such reversals may provide information about underlying olfactory receptor processes. However, the presence of such reversals is rarely acknowledged, few participants and odorants have been tested, and methodological concerns abound.
View Article and Find Full Text PDFCell Rep
April 2024
Center for Neuroscience and Cognitive Systems, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy. Electronic address:
Sampling behaviors have sensory consequences that can hinder perceptual stability. In olfaction, sniffing affects early odor encoding, mimicking a sudden change in odor concentration. We examined how the inhalation speed affects the representation of odor concentration in the main olfactory cortex.
View Article and Find Full Text PDFBMJ Open Respir Res
March 2024
Royal Free London NHS Foundation Trust, London, UK.
Introduction: Patients with neuromuscular disease often have a weak and ineffective cough due to respiratory muscle weakness. One treatment option is mechanical insufflation-exsufflation (MI-E), also known as cough assist, which is known to increase cough strength. However, some patients have a laryngeal response to MI-E, which can make the treatment ineffective.
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