Abnormal global processing along the dorsal visual pathway in autism: a possible mechanism for weak visuospatial coherence?

Abstract

Frith and Happe (Frith, U., & Happe, F. (1994). Autism: Beyond theory of mind. Cognition, 50, 115-132) argue that individuals with autism exhibit 'weak central coherence': an inability to integrate elements of information into coherent wholes. Some authors have speculated that a high-level impairment might be present in the dorsal visual pathway in autism, and furthermore, that this might account for weak central coherence, at least at the visuospatial level. We assessed the integrity of the dorsal visual pathway in children diagnosed with an autism spectrum disorder (ASD), and in typically developing children, using two visual tasks, one examining functioning at higher levels of the dorsal cortical stream (Global Dot Motion (GDM)), and the other assessing lower-level dorsal stream functioning (Flicker Contrast Sensitivity (FCS)). Central coherence was tested using the Children's Embedded Figures Test (CEFT). Relative to the typically developing children, the children with ASD had shorter CEFT latencies and higher GDM thresholds but equivalent FCS thresholds. Additionally, CEFT latencies were inversely related to GDM thresholds in the ASD group. These outcomes indicate that the elevated global motion thresholds in autism are the result of high-level impairments in dorsal cortical regions. Weak visuospatial coherence in autism may be in the form of abnormal cooperative mechanisms in extra-striate cortical areas, which might contribute to differential performance when processing stimuli as Gestalts, including both dynamic (i.e., global motion perception) and static (i.e., disembedding performance) stimuli.

Right Temporoparietal Gray Matter Predicts Accuracy of Social Perception in the Autism Spectrum

“…Our participants showed normal global motion perception as indicated by normal motion coherence thresholds in contrast to previous reports on "hallmark" deficits in global motion perception and reduced perceptual integration in ASD (Spencer et al 2000;Milne et al 2002;Bertone et al 2005;Pellicano et al 2005;Milne et al 2006;Tsermentseli et al 2008;Atkinson 2009). In accordance with our present finding, other psychophysical data also failed to find global motion processing deficits in ASD (Bertone et al 2005;Del Viva et al 2006;de Jonge et al 2007;Sanchez-Marin and Padilla-Medina, 2008;Vandenbroucke et al 2008;Jones et al 2011).…”

“…Impairment of this integration has indeed been reported in ASD (Spencer et al 2000;Milne et al 2002;Pellicano et al 2005;Milne et al 2006;Tsermentseli et al 2008;Atkinson 2009). In addition, individuals with ASD show deficits in the discrimination of biological motion (Blake et al 2003;Parron et al 2008;Klin et al 2009;Annaz et al 2010) and in the recognition of emotions from body movements (Hubert et al 2007;Atkinson 2009), both often tested with "point-light displays" (PLDs) of actions (Johansson 1973).…”

Brief Report: Coherent Motion Processing in Autism: Is Dot Lifetime an Important Parameter?

“…While between-participants variability is often increased in individuals with autism (e.g., Pellicano et al, 2005), the current results show a similar extent of variability in both groups. It remains a possibility that those children with autism who do show reduced coherent motion sensitivity are more susceptible to correspondence noise associated with limited lifetime stimuli (Simmons et al, 2009).…”

Intact Spectral but Abnormal Temporal Processing of Auditory Stimuli in Autism

“…the parvocellular and magnocellular systems) are unaffected in autism (Bertone et al 2005;Pellicano et al 2005). Presumably, the auditory perceptual profile is a consequence of atypical cortical processing as well.…”