Poster F55, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
Oscillatory dynamics differ between nonverbal/minimally-verbal children with ASD and controls during processing of a picture-word matching paradigm.
Silvia Ortiz-Mantilla1, Chiara Cantiani2, Valerie L. Shafer3, April A. Benasich1; 1Center for Molecular and Behavioral Neuroscience, Rutgers University-Newark, NJ, USA, 2Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy, 3The Graduate Center, City University of New York, New York, USA
When children with Autism Spectrum Disorder (ASD) are nonverbal (NV) or minimally-verbal (MV), it is a challenge to determine whether they perceive and comprehend incoming speech information. In a recent ERP study using a picture-word matching paradigm, 4- to 7-year-old MV/NV children with ASD showed relatively intact early sensory processing but abnormal lexical-semantic processing compared to age/gender-matched controls. In adults, processing of semantic incongruence, reflected by the N400 electrophysiological component, is thought to be supported by theta power increases in both match and mismatch conditions but gamma power increases have only been seen for matching information. However, whether similar oscillatory dynamics can index semantic processes in NV/MV children with ASD is unknown. To investigate the oscillatory underpinnings of these ERP responses, source generators were identified and time-frequency analyses were conducted in the 2-90Hz-frequency range within source space. At the perceptual level, 3 sources explained ~90% of variance, while a multi-dipole model explained most of the N400 variance. We found that control children, similar to adults, produced larger frontal gamma power to match than to mismatch conditions whereas ASD children, in general, demonstrated less theta and gamma power than controls for matches but increases in left frontal gamma power for the mismatch. These results align well with the theory that imbalances between inhibitory and excitatory oscillatory activity could be one factor that explains linguistic differences observed in ASD groups and further, may well advance our basic understanding of the neural mechanisms that support both typical and atypical semantic processing in children.
Topic Area: LANGUAGE: Development & aging