Longitudinal development of thalamic and internal capsule microstructure in autism spectrum disorder.

All participants were male, verbal, and without co-occurring intellectual disability, so the findings do not apply to females with ASD, minimally verbal individuals, or people with full-scale IQ less than 70. The groups were not matched on full-scale IQ, and when IQ was not controlled some age-related brain differences became weaker. A scanner hardware change occurred between the first and second time points, although analyses adjusting for it and omitting Time 1 gave similar results. Some participants with ASD were sedated at Time 1 (32 participants) and Time 2 (15 participants), although analyses without sedated scans gave similar results. The study tested 12 separate models, so only a few age-related group differences survived correction. Finger tapping was the only motor outcome, and the mediation model could not test whether the relation changes at different ages. Three-way anterior capsule effects involved few participants in the oldest age ranges.

The supplied text does not report author conflicts. The article is labeled as supported by NIH extramural and non-U.S. government research funding.

Do not read the finger-tapping link as proof that therapy can change posterior internal capsule structure or motor speed. The study measured associations over time in verbal males and did not test treatment.