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Enlarged Right Superior Temporal Gyrus in Children and Adolescents with Autism

The superior temporal gyrus has been implicated in language processing and social perception. Therefore, anatomical abnormalities of this structure may underlie some of the deficits observed in autism, a severe neurodevelopmental disorder characterized by impairments in social interaction and communication. In this study, volumes of the left and right superior temporal gyri were measured using magnetic resonance imaging obtained from 18 boys with high-functioning autism (mean age = 13.5 ± 3.4 years; full-scale IQ = 103.6 ± 13.4) and 19 healthy controls (mean age = 13.7 ± 3.0 years; full-scale IQ = 103.9 ± 10.5), group-matched on age, gender, and handedness. When compared to the control group, right superior temporal gyral volumes were significantly increased in the autism group after controlling for age and total brain volume. There was no significant difference in the volume of the left superior temporal gyrus. Post-hoc analysis revealed significant increase of posterior superior temporal gyral volume in the autism group, before and after controlling for age and total brain volume. Examination of the symmetry index for the superior temporal gyral volumes did not yield statistically significant between-group differences. Findings from this preliminary investigation suggest the existence of volumetric alterations in the right superior temporal gyrus in children and adolescents with autism, providing support for a neuroanatomical basis of the social perceptual deficits characterizing this severe neurodevelopmental disorder.

from Brain Research

Theory of Mind in adults with right hemisphere damage: What’s the story?

Why do people with right hemisphere damage (RHD) have difficulty with pragmatics and communication? One hypothesis has been that pragmatic impairment in RHD is the result of an underlying impairment in Theory of Mind (ToM): the ability to infer the mental states of others. In previous studies evaluating ToM abilities in people with RHD, researchers have used judgment tasks based on story or still cartoon stimuli. However, ToM is likely to draw on kinetic information as well, and these tasks ignore this aspect. The aim of this study was to assess ToM abilities in people with RHD using participants’ evaluations of animated films with moving geometric shapes. Participants were presented with eight films of animated triangles. Four of the films represented the triangles as intentional agents with mental states, while the other four represented the triangles as simply inanimate, though moving, objects. Films were evaluated by both button-press response and by oral descriptions. Analysis of the transcriptions revealed that participants with RHD had a reduced ability to discriminate between the film categories, and a bias toward reduced mental-state ascription in the ToM condition.

from Brain and Language