Brief report: abnormal association between the thalamus and brain size in Asperger's disorder.

The objective of this study was to examine the relationship between thalamic volume and brain size in individuals with Asperger's disorder (ASP). Volumetric measurements of the thalamus were performed on MRI scans obtained from 12 individuals with ASP (age range: 10-35 years) and 12 healthy controls (age range: 9-33 years). A positive correlation was found between total brain volume and thalamic size in controls, but not in ASP subjects. This occurred in the absence of differences in mean thalamic volumes between the study groups. Findings from this investigation point to an abnormal relationship between the thalamus and its projection areas in ASP and are consistent with similar studies in autism, supporting that these disorders are qualitatively similar and possibly quantitatively different.