Disrupted Neural Synchronization in Toddlers with Autism

Abstract

Summary Autism is often described as a disorder of neural synchronization. However, it is unknown how early in development synchronization abnormalities emerge and whether they are related to the development of early autistic behavioral symptoms. Here, we show that disrupted synchronization is evident in the spontaneous cortical activity of naturally sleeping toddlers with autism, but not in toddlers with language delay or typical development. Toddlers with autism exhibited significantly weaker inter-hemispheric synchronization (i.e. weak “functional connectivity” across the two hemispheres) in putative language areas. The strength of synchronization was positively correlated with verbal ability, negatively correlated with autism severity, and enabled identification of the majority of autistic toddlers (72%) with high accuracy (84%). Disrupted cortical synchronization, therefore, appears to be a notable characteristic of autism neurophysiology that is evident at very early stages of autism development.

Atypical Bilateral Brain Synchronization in the Early Stage of Human Voice Auditory Processing in Young Children with Autism

“…As indicated in Fig 6A and 6B, children with ASD tended to exhibit higher Omega complexities than TD children in many time windows (such as time windows from 0 to 600 ms), which suggests that the former children exhibit reduced whole brain synchronization relative to the latter children. Our results are consistent with several recent reports of reduced brain hemodynamic synchronization in young children, adolescents and adults with ASD [55][56][57][58][59]. Two recent studies reported significantly decreased inter-hemispheric synchronization in toddlers with ASD [55] and in adolescents and adults with ASD [56].…”

“…Our results are consistent with several recent reports of reduced brain hemodynamic synchronization in young children, adolescents and adults with ASD [55][56][57][58][59]. Two recent studies reported significantly decreased inter-hemispheric synchronization in toddlers with ASD [55] and in adolescents and adults with ASD [56]. Structural imaging has also demonstrated abnormalities in inter-hemispheric long-range white matter pathways.…”

Epilepsy and Autism

“…Similar to the rodent studies, there is increasing evidence from both imaging and neurophysiologic studies pointing to altered brain connectivity as a key feature of the pathophysiology of ASD (Casanova and Trippe 2009;Dinstein et al 2011;Kana et al 2011;Muller et al 2011). Additionally, there is some evidence that the changes in neuronal organization in ASD are differentially expressed with age, marked by early life brain overgrowth including increased neuron number, followed by decreases in both structural volumes and neuron number as the brain ages.…”

Early Screening of Autism Spectrum Disorder: Recommendations for Practice and Research

“…• Geographic area 98 recorded functional MRI activity from 63 naturally sleeping toddlers with ASD, language disorder (ie, standardized score at least 1 SD below the mean), or typical development. Relative to the other groups, toddlers with an ASD exhibited significantly weaker interhemispheric correlations in the inferior frontal gyrus and superior temporal gyrus, 2 areas central to language production and comprehension.…”