2. Electrophysiology: EEG/ERP It has long been known that some children with ASD fail to respond when spoken to, cover their ears in the presence of certain sounds, yet show highly acute hearing in other contexts. Little is known about the mechanisms that might underlie these unusual auditory processing profiles. Abnormal neural oscillations have been found to be an endophenotype for ASD in infants and adults. However, the picture of how oscillations differ from those of non-clinical subjects is unclear and depends on the age at testing. Characterizing the oscillations present in the brains of a range of adolescents will allow us to quantify the relationship between neural activity and severity of language impairment. The main hypothesis that will be tested in this project is that abnormal neural connectivity in minimally verbal children with ASD profoundly impedes the ability to perceptually organize auditory scenes into meaningful units or objects, which has a direct effect on language development in these individuals. Event-related brain potentials (ERPs) and frequency-based analysis of the electroencephalogram (EEG) will be collected during passive listening tasks, to evaluate auditory perception and the perceptual organization of tones and speech using the mismatch negativity (MMN) paradigm (the MMN reflects passive deviance detection processes indexing low-level acoustic processes in automatic sensory memory mechanisms, and it has been widely investigated in studies of auditory perceptual discrimination of tones and speech).