Table 2.

Significant clusters for group comparisons made across all ages and in children only

Cluster location	t-map threshold	Cluster size threshold (mm2)	Cluster size in mm2 (p value)	Stereotaxic coordinates			Depth difference (mm)	% Difference relative to TD average sulcal depth
				x	y	z
All ages
LFA (n = 17)	L frontal operculum	−2.69	316	793 (0.01)	−37	4	9	2.6	13
HFA (n = 14)	Bilateral parietal operculum	5.40	162	420 (0.005)	±43	−12	16	1.7	8
ASP (n = 15)	Bilateral intraparietal sulcus	5.40	158	278 (0.017)	±28	−67	37	4.5	41
Children (7.5–12.5 years)
LFA (n = 8)	L operculum	−2.78	407	1568 (<0.0001)	−38	−3	5	3.5
HFA (n = 8)	Bilateral parietal operculum	5.56	205	402 (0.006)	±44	−14	18	2.1	9
ASP (n = 8)	Bilateral intraparietal sulcus	5.56	195	496 (0.0012)	±27	−69	37	5.6	52

No significant clusters were identified in the analyses restricted to adolescents (12.75–18.5 years). Bilateral clusters were identified by interhemispheric correlation analyses, and unilateral clusters were identified by cluster size analyses. Different t-values (corresponding to p < 0.01) were used to generate t-maps for each comparison. Separate permutation analyses to determine significant cluster size thresholds were carried out for each comparison. Actual cluster sizes all surpassed the size thresholds and corresponding p values were corrected for multiple comparisons to the same TD control group. For each cluster, the depth difference reflects how much deeper the ASD group was relative to the TD controls. The depth difference is also depicted as the percentage difference relative to TD controls average depth. Cluster size refers to surface area of the cluster on the PALS average fiducial surface compensated for the average distortion relative to individual fiducial surfaces. L, Left.