Cortical activation and synchronization during sentence comprehension in high-functioning autism: evidence of underconnectivity

TLDR

The study proposes a neurobiological explanation for underconnectivity in autism based on fMRI findings during sentence comprehension. Functional MRI was used to compare activation patterns and functional connectivity during sentence comprehension between high‑functioning autistic participants and IQ‑matched controls. Autistic participants showed increased activation in Wernicke's area, decreased activation in Broca's area, and reduced functional connectivity across language regions, indicating impaired integration during sentence comprehension.

Abstract

The brain activation of a group of high-functioning autistic participants was measured using functional MRI during sentence comprehension and the results compared with those of a Verbal IQ-matched control group. The groups differed in the distribution of activation in two of the key language areas. The autism group produced reliably more activation than the control group in Wernicke's (left laterosuperior temporal) area and reliably less activation than the control group in Broca's (left inferior frontal gyrus) area. Furthermore, the functional connectivity, i.e. the degree of synchronization or correlation of the time series of the activation, between the various participating cortical areas was consistently lower for the autistic than the control participants. These findings suggest that the neural basis of disordered language in autism entails a lower degree of information integration and synchronization across the large-scale cortical network for language processing. The article presents a theoretical account of the findings, related to neurobiological foundations of underconnectivity in autism.