Autism, Asperger syndrome and brain mechanisms for the attribution of mental states to animated shapes

Examined brain mechanisms associated with attribution of mental states to animated shapes among 10 adults with autism or Asperger syndrome (mean age 33 yrs) and 10 normal subjects (Ss [mean age 25 yrs]). Ss were PET scanned while watching animated sequences. The animations depicted 2 triangles moving about on a screen in 3 different conditions: moving randomly, moving in a goal-directed fashion, and moving interactively with implied intentions. The last condition frequently elicited descriptions in terms of mental states that viewers attributed to the triangles (mentalizing). The autism group gave fewer and less accurate descriptions of these latter animations, but equally accurate descriptions of the other animations compared with controls. While viewing animations that elicited mentalizing, in contrast to randomly moving shapes, the normal Ss showed increased activation in a previously identified mentalizing network (medial prefrontal cortex, superior temporal sulcus at the temporo-parietal junction and temporal poles). The autism group showed less activation than the normal group in all these regions. Results suggest a physiological cause for the mentalizing dysfunction in autism: a bottleneck in the interaction between higher- and lower-order perceptual processes. (PsycINFO Database Record (c) 2003 APA, all rights reserved