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Insistence on sameness relates to increased covariance of gray matter structure in autism spectrum disorder.

Eisenberg IW, Wallace GL, Kenworthy L, Gotts SJ, Martin A - Mol Autism (2015)

Bottom Line: Subcortical structural changes have been associated with restricted and repetitive behavior (RRB), a core component of ASD.We found that increased coupling among subcortical regions and between subcortical and cortical regions related to greater IS symptom severity.These structural associations were specific to IS and did not relate to any of the other RRB subcomponents measured by the RBS-R.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, MD USA.

ABSTRACT

Background: Autism spectrum disorder (ASD) is characterized by atypical development of cortical and subcortical gray matter volume. Subcortical structural changes have been associated with restricted and repetitive behavior (RRB), a core component of ASD. Behavioral studies have identified insistence on sameness (IS) as a separable RRB dimension prominent in high-functioning ASD, though no simple brain-behavior relationship has emerged. Structural covariance, a measure of morphological coupling among brain regions using magnetic resonance imaging (MRI), has proven an informative measure of anatomical relationships in typical development and neurodevelopmental disorders. In this study, we use this measure to characterize the relationship between brain structure and IS.

Methods: We quantified the structural covariance of cortical and subcortical gray matter volume in 55 individuals with high-functioning ASD using 3T MRI. We then related these structural metrics to individual IS scores, as assessed by the Repetitive Behavior Scale-Revised (RBS-R).

Results: We found that increased coupling among subcortical regions and between subcortical and cortical regions related to greater IS symptom severity. Most pronounced, the striatum and amygdala participated in a plurality of identified relationships, indicating a central role for these structures in IS symptomatology. These structural associations were specific to IS and did not relate to any of the other RRB subcomponents measured by the RBS-R.

Conclusions: This study indicates that behavioral dimensions in ASD can relate to the coordination of development across multiple brain regions, which might be otherwise obscured using typical brain-behavior correlations. It also expands the structures traditionally related to RRB in ASD and provides neuroanatomical evidence supportive of IS as a separate RRB dimension.

Trial registration: ClinicalTrials.gov NCT01031407.

No MeSH data available.


Related in: MedlinePlus

Intra-subcortical median-split analysis. Intra-subcortical volume Region X Region covariance matrices shown for a the high IS group, b low IS group, and c high-low difference. Color indicates the Pearson r value, or, in c, the r value difference. In c, the three differences surviving correction for multiple comparisons are displayed in the lower triangle. Tha thalamus, Cau caudate, Put putamen, Pal pallidum, Hip hippocampus, Amy amygdala, Acc nucleus accumbens
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Fig1: Intra-subcortical median-split analysis. Intra-subcortical volume Region X Region covariance matrices shown for a the high IS group, b low IS group, and c high-low difference. Color indicates the Pearson r value, or, in c, the r value difference. In c, the three differences surviving correction for multiple comparisons are displayed in the lower triangle. Tha thalamus, Cau caudate, Put putamen, Pal pallidum, Hip hippocampus, Amy amygdala, Acc nucleus accumbens

Mentions: As described in the methods, two approaches were taken to assess structural covariance of subcortical structures and IS, a split-half group comparison and a continuous correlational approach. The relationship between IS and structural covariance was first assessed by a group comparison (between high and low IS groups). The high IS group had greater inter-regional correlations than the low IS group (high IS: r = .69 ± .09; low IS: r = .25 ± .24); out of 21 possible unique region pairs, three subcortical regional pairs survived correction for multiple comparisons (p < .05 via random permutation/Monte-Carlo): amygdala-pallidum, amygdala-accumbens, and hippocampus-pallidum (Fig. 1).Fig. 1


Insistence on sameness relates to increased covariance of gray matter structure in autism spectrum disorder.

Eisenberg IW, Wallace GL, Kenworthy L, Gotts SJ, Martin A - Mol Autism (2015)

Intra-subcortical median-split analysis. Intra-subcortical volume Region X Region covariance matrices shown for a the high IS group, b low IS group, and c high-low difference. Color indicates the Pearson r value, or, in c, the r value difference. In c, the three differences surviving correction for multiple comparisons are displayed in the lower triangle. Tha thalamus, Cau caudate, Put putamen, Pal pallidum, Hip hippocampus, Amy amygdala, Acc nucleus accumbens
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4591718&req=5

Fig1: Intra-subcortical median-split analysis. Intra-subcortical volume Region X Region covariance matrices shown for a the high IS group, b low IS group, and c high-low difference. Color indicates the Pearson r value, or, in c, the r value difference. In c, the three differences surviving correction for multiple comparisons are displayed in the lower triangle. Tha thalamus, Cau caudate, Put putamen, Pal pallidum, Hip hippocampus, Amy amygdala, Acc nucleus accumbens
Mentions: As described in the methods, two approaches were taken to assess structural covariance of subcortical structures and IS, a split-half group comparison and a continuous correlational approach. The relationship between IS and structural covariance was first assessed by a group comparison (between high and low IS groups). The high IS group had greater inter-regional correlations than the low IS group (high IS: r = .69 ± .09; low IS: r = .25 ± .24); out of 21 possible unique region pairs, three subcortical regional pairs survived correction for multiple comparisons (p < .05 via random permutation/Monte-Carlo): amygdala-pallidum, amygdala-accumbens, and hippocampus-pallidum (Fig. 1).Fig. 1

Bottom Line: Subcortical structural changes have been associated with restricted and repetitive behavior (RRB), a core component of ASD.We found that increased coupling among subcortical regions and between subcortical and cortical regions related to greater IS symptom severity.These structural associations were specific to IS and did not relate to any of the other RRB subcomponents measured by the RBS-R.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, MD USA.

ABSTRACT

Background: Autism spectrum disorder (ASD) is characterized by atypical development of cortical and subcortical gray matter volume. Subcortical structural changes have been associated with restricted and repetitive behavior (RRB), a core component of ASD. Behavioral studies have identified insistence on sameness (IS) as a separable RRB dimension prominent in high-functioning ASD, though no simple brain-behavior relationship has emerged. Structural covariance, a measure of morphological coupling among brain regions using magnetic resonance imaging (MRI), has proven an informative measure of anatomical relationships in typical development and neurodevelopmental disorders. In this study, we use this measure to characterize the relationship between brain structure and IS.

Methods: We quantified the structural covariance of cortical and subcortical gray matter volume in 55 individuals with high-functioning ASD using 3T MRI. We then related these structural metrics to individual IS scores, as assessed by the Repetitive Behavior Scale-Revised (RBS-R).

Results: We found that increased coupling among subcortical regions and between subcortical and cortical regions related to greater IS symptom severity. Most pronounced, the striatum and amygdala participated in a plurality of identified relationships, indicating a central role for these structures in IS symptomatology. These structural associations were specific to IS and did not relate to any of the other RRB subcomponents measured by the RBS-R.

Conclusions: This study indicates that behavioral dimensions in ASD can relate to the coordination of development across multiple brain regions, which might be otherwise obscured using typical brain-behavior correlations. It also expands the structures traditionally related to RRB in ASD and provides neuroanatomical evidence supportive of IS as a separate RRB dimension.

Trial registration: ClinicalTrials.gov NCT01031407.

No MeSH data available.


Related in: MedlinePlus