The objective of this study is to characterize the normal neuromagnetic profile of sensorimotor, auditory, visual, and language cortices in children and adults using magnetoencephalography (MEG) and three new signal-processing techniques.

MEG is a new powerful tool for noninvasively measuring neuromagnetic signals originating from the brain. Since MEG can detect neuromagnetic signals with high spatial and temporal resolution, many brain properties can be studied. For pediatric purposes, MEG can (1) evaluate the functionalities of the sensorimotor, auditory, visual, and language systems non-invasively during normal maturation; (2) identify abnormalities in these functionalities that occur with neurological or neurodevelopmental disorders; and (3) provide a pre-operative "functional map" for neurosurgeons to improve surgical outcomes and decrease morbidity and mortality.

Previously MEG has been used to provide a single three-dimensional point that estimates the 'center' of cortical regions [1,2]. In this study three new techniques will be used to extend the usefulness of MEG beyond this point-like estimate of a cortical primary sensory input or motor output region. The three new techniques are independent component analysis, S-transform, and magnetic spatial filtering. The three new techniques for data analysis will be used in conjunction with non-invasive MEG data collection. The three techniques will provide us with the following important information about the brain: (1) the patterns of synchronization and de-synchronization of evoked cortical activation and (2) the volumetric extent of these active sensorimotor, auditory, visual and language cortices in children and adults. This approach may lead to a new way to study the brain functions in normal children and in children with various brain disorders.