The Neurodiversity of Motor Stereotypies: Elucidating Common Brain-Behavior Relationships Across Sensory Landscapes

We live in an ever-constant Ʋuctuation of sensory input, and navigating this can be easily overwhelming. To remedy this, our brains have devised sensory sampling behaviors to rhythmically parse out this input and optimize sensory processing by weighting sensory experiences time-locked to behavior while dampening behaviorally unrelated neural activity. Such “active sensing” is commonly achieved through rhythmic behaviors such as sniffing and saccadic eye movements and can be mechanistically explained by the combination of neural entrainment and phase-amplitude coupling (PAC). Neural entrainment describes the alignment of peak neural excitability to the phase of self-generated sensory input, allowing the brain to better predict and process incoming information. This entrainment can further improve sensory processing through PAC, in which the timing of lower-frequency oscillations (e.g., delta) modulates more localized higher-frequency oscillations (e.g., gamma) associated with sensory processing, enhancing coordination across different brain regions and frequencies. Rhythmic behaviors exist in many forms, with some being less obvious in sensory function, such as motor stereotypies (STY). STY are highly rhythmic and stereotyped behaviors prevalent in autism but also observed in the neurotypical (NT) population, albeit less frequently. Traditionally presumed purposeless, flrst-person accounts by autistics and NTs suggest STY serve as coping behaviors to reduce sensory under/overstimulation from the environment. Our flrst aim probes the relationship between rhythmic behavior and environmental sensory stimulation across diagnosis. We will collect motion-tracking data and ambulatory EEG from autistic and non-autistic children and adolescents (5–17 years) while they explore augmented reality environments of low, medium, and high sensory stimulation. In pursuit of this goal, we will use video recordings and motion-tracking data to build a database for the automated classiflcation of motor stereotypies. We hypothesize motor rhythmicity differences across diagnostic groups and environmental conditions, expecting increased rhythmic movement in autistics compared to neurotypicals, and increased motor rhythmicity during low- and high-sensory stimulation conditions. Our second aim explores the neural mechanisms underlying the sensory processing beneflts of STY. We hypothesize that STY serve an active sensing role in both autistics and NTs by entraining low-frequency neural oscillations, with reduced entrainment and delta-gamma PAC in autistic participants. This novel framework of STY may inform how we design sensory environments to tailor individual sensory needs and assist autistics in developing more efficient sensing behaviors. Project Number: 1F31MH142089-01 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of Mental Health (NIMH) | Principal Investigator: William Quackenbush | Institution: VANDERBILT UNIVERSITY, Nashville, TN | Award Amount: $34,980 | Activity Code: F31 | Study Section: Special Emphasis Panel[ZRG1 F02B-H (20)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11243901