Table 3.

Significant differences in relative regional white matter volume between participants with ASD and TDC participants, after controlling for full-scale IQ

Tract-specific label	Nearest gray matter region	Hemisphere	MNI coordinates			T value	Cluster-level P value a	Cluster size (voxels)
			x	y	z
Model 1: ASD > TDC
Splenium of corpus callosum	Precuneus	L	−18	−48	4	4.19	0.015	655
	Precuneus	L	−19	−46	21	3.57
	Posterior cingulate gyrus	L	−16	−33	39	3.46
Splenium of corpus callosum	Posterior cingulate gyrus	R	21	−46	6	3.65	0.009	715
	Precuneus	R	23	−46	24	3.46
	Posterior cingulate gyrus	R	18	−30	30	3.27
Model 2: ASD > TDC
External capsule/anterior corona radiata	Inferior orbitofrontal cortex	R	23	20	−18	4.54	0.041	537
		R	26	32	−11	4.04
		R	18	32	−18	3.64
Splenium of corpus callosum	Precuneus	L	−18	−48	4	4.31	0.016	644
	Precuneus	L	−19	−46	21	3.61
	Posterior cingulate gyrus	L	−16	−33	39	3.43
Splenium of corpus callosum	Posterior cingulate gyrus	R	21	−46	7	3.60	0.011	690
	Precuneus	R	23	−46	24	3.42
	Posterior cingulate gyrus	R	18	−30	30	3.30
Model 2: ASD by age > TDC by age
Forceps minor (anterior forceps)	Anterior cingulate gyrus	L	−18	45	4	4.14	0.001	960
		L	−25	20	−5	3.46
		L	−18	29	−2	3.33
Model 3: Adolescent, ASD > TDC
Anterior corona radiata	Anterior cingulate gyrus	R	12	29	−9	4.10	0.001	1,151
		R	29	21	10	3.84
		R	26	39	−5	3.74

ASD, autism spectrum disorder; TDC, typically developing control; L, left; R, right; MNI, Montreal Neurological Institute. ^aStatistical threshold was all set at FWE-corrected cluster-level P < 0.05, with cluster-forming voxel-level P < 0.005.