Sample Composition
1114 subjects were included from 19 sites. 399 ASD patients (336 males, 63females) and 441normal controls (NCs, 298 males, 143 females) aged less than or equal to 18 years. To decrease the sample sex bias between two groups, we randomly included (Matlab randperm function) 361 ASD patients (298 males, 63 females) and 361 HCs (298 males, 63 females) in the latter ALFF analysis. No age differences were observed in the two groups. The mean and SD of Social Responsiveness Scale total T scores in ASDs and NCs is 76.67 ± 13.42 and 43.89 ± 6.38 respectively. The detailed demographic and id lists of the participants are shown in Supplementary Table 1 and Supplementary Table 2.
ALFF changes of cerebellum regions between ASDs and NCs
To test the spontaneous brain activity differences between ASDs and NCs, ALFF analysis was performed. Six clusters were obtained and the locations were assigned by using AAL2 template. Significant differences were located in extensive cerebellar regions involving two clusters: cluster 1(cerebellum_crus2_R, crebelum_crus2_L) and cluster 2 (cerebellum 4 5 L, cerebellum 6L and vermis 4 5). However, these two clusters in ASDs showed different changes in ALFF value. The regions of cluster 1 in ASDs showed decreased ALFF value than those in NCs while cluster 2 in ASDs showed increased ALFF value (Fig. 1, Table 1). It should be noted that other brain regions were observed to also show dramatical changes in ASD. These regions included supplementary motor Area (SMA), cingulum mid, thalamus, basal ganglia (caudate, putamen) and occipital regions, etc (Fig. 1, Table 1).
Table 1
Brain regions showing significant differences on ALFF analysis between ASD patients and healthy controls*.
Clusters | Peak MNI coordinate | Peak intensity | Cluster size | BA | Structure(voxels) |
x | y | z |
Cluster 1 | 45 | -63 | -51 | -4.49 | 111 | \ | Cerebellum_Crus2_R (51) |
Cluster 2 | -39 | -75 | -36 | -4.66 | 229 | \ | Cerebellum_Crus2_L (180) |
Cluster 3 | -15 | -51 | -21 | 5.22 | 342 | \ | Cerebellum_4_5_L(100) |
| | | | | | | Cerebellum_6_L(68) |
| | | | | | | Vermis_4_5(54) |
Cluster 4 | -51 | -57 | -24 | -5.33 | 84 | 37 | Temporal_Inf_L(23) |
Cluster 5 | -6 | 0 | 60 | 6.29 | 6467 | 6 | Supp_Motor_Area_L(330) |
| | | | | | | Supp_Motor_Area_R(330) |
| | | | | | | Cingulum_Mid_L(190) |
| | | | | | | Cingulum_Mid_R(181) |
| | | | | | | Thalamus_R(180) |
| | | | | | | Thalamus_L(145) |
| | | | | | | Caudate_R(130) |
| | | | | | | Putamen_L(126) |
| | | | | | | Hippocampus_L(121) |
| | | | | | | Hippocampus_R(114) |
| | | | | | | Frontal_Sup_Medial_L(113) |
| | | | | | | Frontal_Inf_Orb_L(110) |
| | | | | | | Caudate_L(107) |
| | | | | | | Precentral_L(105) |
| | | | | | | Frontal_Sup_R(103) |
| | | | | | | Putamen_R(103) |
| | | | | | | Paracentral_Lobule_L(84) |
| | | | | | | Precuneus_L(55) |
| | | | | | | Paracentral_Lobule_R(51) |
| | | | | | | Pallidum_L(51) |
Cluster 6 | 12 | -93 | 0 | -5.32 | 635 | 17 | Calcarine_R(91) |
| | | | | | | Calcarine_L(106) |
| | | | | | | Occipital_Mid_L(87) |
| | | | | | | Occipital_Inf_L(84) |
Cluster 7 | -48 | 48 | 12 | 5.51 | 85 | \ | Frontal_Inf_Tri_L(24) |
*Two sample t test and two tailed TFCE correction with PALM permutation test were used (P < 0.005, number of permutations 1000). The locations were assigned by using a Matlab tool Xjview. Edge cluster connectivity criterion, rmm = 5, cluster size > = 50 voxels. The surface view maps were shown in Fig. 1. |
ALFF values of spontaneous brain activity was correlated with Clinical trait
Considering that four subregions of cerebellum (cerebellum crus 2, left cerebellum 4 5, left cerebellum 6, cerebellum vermis 4 5),putamen, SMA and thalamus showed significantly altered ALFF in ASDs, we hypothesized that these changes in ALFF, depicting the spontaneous brain activity might be associated with clinical traits. Therefore, to examine the relationship between alteration of ALFF and clinical trait, Pearson correlation analyses were performed between SRS T scores including SRS total T score, SRS awareness T score, SRS cognition T score, SRS communication T score, SRS motivation T score and SRS mannerisms T score and mean ALFF values of these ROIs. ROIs regions including left cerebellum crus 2, left cerebellum 4 5, left cerebellum 6, cerebellum vermis 4 5, putamen, thalamus and SMA were defined using AAL2 template (Rolls, et al., 2015). The mean ALFF values of each ROI for individuals were extracted from corresponding ALFF results.
We noted that in juvenile ASD patients with SRS total T scored above 59 (n = 258), the mean ALFF value of cerebellum vermis 4 5 was significantly correlated with SRS Total T(r = 0.175,P = 0.031, FDR correction), SRS cognition T (r = 0.169,P = 0.036) and SRS motivation T(r = 0.176, P = 0.028), These findings were not obtained in NC group. After FDR correction, the ALFF values of other regions including left cerebellum crus 2, left cerebellum 4 5, and left cerebellum 6, Putamen, Thalamus and SMA showed no significant correlations with SRS scores. Moreover, in NC group, we found the ALFF values of left cerebellum crus 2 was dramatically negatively related to SRS motivation score T (r = − 0.158, P = 0.014), which was not found in ASD patients (Fig. 2, Supplementary Table 2,3).
Findings from comparisons of ALFF values between ASDs and NCs
To explore the ALFF trends in ASDs, we further compared the mean ALFF values of ROIs between ASDs and NCs. The sample was same as the ALFF analysis. It was noted that the ASD group showed increased ALFF values that of NCs in left cerebellum 6 (P = 0.001, t = 3.209, Cohen’ d = 0.239), cerebellum vermis 4 5 (P = 0.039, t = 2.071, Cohen’ d = 0.154), putamen (P < 0.01, t = 3.339, Cohen’ d = 0.249), thalamus (P < 0.001, t = 4.355, Cohen’ d = 0.325) and SMA (P < 0.001, t = 4.530, Cohen’ d = 0.338). However, the mean ALFF values of left cerebellum crus 2 in ASD patients were lower than that of NCs (P < 0.001, t=-4.165, Cohen’ d=-0.310). The two groups presented no significant differences in the ALFF values of left cerebellum 4 5 (Fig. 3).
Medication effect and ALFF values of ROIs
Considering that medication might have potential impacts on spontaneous brain activity of ROIs, we divided the ASDs into two groups according to their medication status. We found that the ALFF differences between ASDs with medications (n = 84) and ASDs without medication (n = 172) did not survive after FDR adjusted.
Reproducibility
We assessed reproducibility through a simple strategy. We randomly selected (with Matlab) another two sex- and age- matched groups and carried out ALFF analysis. The results of ALFF analysis remained the same with same settings as previous analysis (Supplementary Fig. 1). Then, we defined the ROIs based on AAL2 atlas, not based on our own ALFF clusters.