Abstract This R61/R33 project will develop an advanced technology for non-invasive recording of whole-brain physiology with synchronized video-tracking of movement for use in children with intellectual disability and will use it to elucidate the brain-circuit electrophysiology of intellectual development. The technological advances will have immediate benefits for pediatric neurology and will be widely applicable to many neurological disorders in which safe and convenient, non-invasive recordings of brain physiology are desired to inform diagnosis, prognosis, and treatment. The R61 phase will be performed by FieldLine Medical (Boulder, CO) which will contribute their recent advances in optically-pumped magnetometer magnetoencephalography (OPM-MEG), a transformative technology for safe, physiological brain imaging that greatly increases sensitivity to brain electrical signals as compared to SQUID-MEG and EEG and provides greater coverage than invasive electrophysiology. FieldLine will: 1) expand the capabilities of their HEDscan OPM-MEG system, as a “wearable” brainwave scanning technology, for high-fidelity MEG recordings in freely moving children; and 2) integrate synchronized video- tracking of voluntary movements for kinematic analysis to create a technology named HEDscanV. The R33 phase will deploy HEDscanV in two pediatric neuroscience laboratories at the Children's Hospital of Philadelphia and Seattle Children's Research Institute. After validating HEDscanV in children against SQUID-MEG, the R33 phase will leverage advances in autism research enabled by sensory, motor, and associative learning paradigms that were developed by the MPIs to identify intellectual disability with high accuracy. By disseminating HEDscanV and sensory-motor paradigms across clinical sites in Philadelphia and Seattle, we will work together to identify the bandwidths of electrical activity coherence in brain circuits at the interface of movement and cognition that promote intellectual development. Our success will be ensured by the support of two nationally-recognized autism centers at the University of Washington and Children's Hospital of Philadelphia, where high-fidelity clinical assessments and diagnostic testing will be conducted. By establishing the locations and bandwidths of activity coherence in the brains of children that promote intellectual development, the project will begin to lay the essential groundwork needed to establish therapies intending to normalize brain pathophysiology and facilitate intellectual development in children with neurodevelopmental disorders.