To gain insight into the development of brain dysfunction in autism spectrum disorder (ASD), it is necessary to study the pathophysiology of ASD in young children. However, it is challenging to measure brain activities in young children with ASD under conscious conditions because they are not always cooperative or patient. Therefore, since 2008, we developed a child-friendly device:a custom child-sized MEG system in which the sensors are located as close to the head as possible for optimal recording, even in young children. This is a useful system that can provide measures of cortical activity on a millisecond timescale. In addition, the custom child-sized MEG has advantages over other neuroimaging techniques for young children, including having fewer constraints and causing less environmental noise. Using this device, we have reported aberrant brain activity and brain functional connectivity in pre-school children with ASD under conscious conditions. Recently, to investigate the underlying neural mechanism behind human reciprocal interactions, we recently developed a MEG hyperscanning system to examine brain-to-brain interactions between a mother and child during face-to-face interaction. Our results from the pilot study demonstrated that the brain activities in ASD children and their mothers during their face-to-face interaction reflects their social ability or autistic traits. We believe that this kind of neuroimaging study will bridge the gap between genetics and developmental psychology.
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