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

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.

Intact Spectral but Abnormal Temporal Processing of Auditory Stimuli in Autism

“…Although these hypothesises are still in need of empirical confirmation and the current study does not directly validate or falsify them, they may be relevant for the current findings. Atypical neural connectivity refers to the underfunctioning of integrative neural circuitry resulting in a deficient integration of information at neural and cognitive levels (Just et al 2004). Reduced functional synchrony between cortical regions has been proposed as an explanation for the perceptual performance in autism because higher levels of performance on simple low-level patterns may be a consequence of analysis by a single or a few dedicated brain regions (Bertone et al 2005).…”

Computational prosodic markers for autism

“…Some studies indicate that temporal processing of auditory (including speech) input may be impaired in ASD (e.g., Cardy, Flagg, Roberts, Brian, & Roberts, 2004; Groen, van Orsouw, ter Huurne, Swinkels, van der Gaag, Buitelaar, et al, 2009), while pitch sensitivity may be a relative strength (e.g., Bonnel, Mottron, Peretz, Trudel, Gallun, E., & Bonnel, 2003). It is possible that inter-hemispheric underconnectivity in ASD (e.g., Just, Cherkassky, Keller, & Minshew, 2004) plays an additional role, resulting in poor coordination of pitch and temporal processing, thereby undermining any indirect benefit bestowed on temporal processing by intact pitch processing.…”

Sensory Sensitivities and Performance on Sensory Perceptual Tasks in High-functioning Individuals with Autism

“…Minshew and colleagues have proposed that impairments in higher cortical sensory perception are but one of many manifestations of a more generalized deficit in complex information processing (Minshew, Goldstein & Siegel, 1997) resulting from alterations in the brain connectivity of cortical systems (Just, Cherkassky, Keller, & Minshew, 2004). This dissociation between intact elementary sensory perceptual abilities is consistent with the The neuropsychologic tests commonly used to assess sensory perception are the LuriaNebraska Battery, Tactile Functions Domain (Golden, Hammeke, & Purisch, 1980) and the Reitan-Klove, Sensory Perceptual Exam (Reitan & Wolfson, 1993).…”

“…Perceptual biases for details and a heightened sensitivity to unique, rather than shared, stimulus features may underlie the autistic "need for sameness" (Happé, 1999). Thus, the characteristic cognitive strengths found in autism, such as heightened processing of features and hyper-focus on details, often those that are inconsequential or insignificant, may be linked with or exacerbate sensory processing abnormalities.Minshew and colleagues have proposed that impairments in higher cortical sensory perception are but one of many manifestations of a more generalized deficit in complex information processing (Minshew, Goldstein & Siegel, 1997) resulting from alterations in the brain connectivity of cortical systems (Just, Cherkassky, Keller, & Minshew, 2004). This dissociation between intact elementary sensory perceptual abilities is consistent with the The neuropsychologic tests commonly used to assess sensory perception are the LuriaNebraska Battery, Tactile Functions Domain (Golden, Hammeke, & Purisch, 1980) and the Reitan-Klove, Sensory Perceptual Exam (Reitan & Wolfson, 1993).…”