International Meeting for Autism Research (London, May 15-17, 2008): Analysis of the Basal Ganglia Morphometry in Autism Using Large Deformation Diffeomorphic Metric Mapping (LDDMM)

Saturday, May 17, 2008

Champagne Terrace/Bordeaux (Novotel London West)

11:30 AM

D. Crocetti , Laboratory for Neurocognitive and Imaging Research, Kennedy Krieger Institute, Baltimore, MD

A. Qui , Johns Hopkins University, Baltimore, MD

M. C. Adler , Teachers College at Columbia University, New York, NY

M. I. Miller , Center for Imaging Science, Johns Hopkins University, Baltimore, MD

S. H. Mostofsky , Laboratory for Neurocognitive and Imaging Research (KKI), Departments of Neurology and Psychiatry (JHU), Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD

Background: Studies have shown that autism is associated with abnormalities suggestive of basal ganglia dysfunction, including repetitive and stereotyped patterns of behavior and consistent findings of abnormalities in motor examination. Neuroimaging investigations of basal ganglia structures have thus far been limited to examination of whole volume analysis and are prone to missing localized abnormalities. Large deformation diffeomorphic metric mapping (LDDMM), a powerful computational tool used for detailed analysis of the morphology (e.g., shape, thickness) of cortical/subcortical brain regions, may provide better understanding of differences in basal ganglia structures.

Objectives: To apply LDDMM to detailed analysis of basal ganglia structure in children with autism.

Methods: The structures of the basal ganglia (caudate, nucleus accumbens, putamen, globus pallidus) were manually delineated in 23 (5 females) children with autism and 23 (5 females) unaffected controls, ages 8-12 years. LDDMM was then used to map and assess differences in shape across each structure. To test significance, we performed a principal components expansion on the vector displacement fields of the subjects, extracted a small number of components using a scree plot, then performed a standard permutation test of the significance of the group differences using these coefficients.

Results: The findings revealed the anterior portion of the right putamen to be significantly contracted in children with autism compared to controls; in contrast the posterior portion was significantly expanded.

Conclusions: The findings suggest abnormalities in the structure of the putamen, which has been linked to “sensorimotor” and “associative” (visuo-motor) functioning, and have demonstrated how a detailed analysis of shape can provide greater insight into the structural abnormalities associated with autism. These methods can also be applied to examination of brain-behavioral correlations and may prove to be more valuable in identifying neuroanatomic biomarkers of autism.

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