Explainable Deep Learning of Resting-State Functional Connectomes Reveals Network Biomarkers of Adolescent Intelligence
Authors: Md. Tanvir Rahman, Nabil Anan Orka, Asaduzzaman Khan, Mohammad Ali Moni
Organizations: School of Health and Rehabilitation Sciences, The University of Queensland, QLD 4072, Australia · Department of Information and Communication Technology, Mawlana Bhashani Science and Technology University, Tangail 1902, Bangladesh
Mapping resting-state brain organization to individual differences in cognitive ability remains a major challenge in population neuroinformatics. Although deep learning enables flexible modeling of brain connectivity, limited interpretability restricts its scientific and clinical utility. To address this objective, we developed an explainable deep learning framework based on sparse projected residual networks to predict fluid, crystallized, and total intelligence from resting-state functional magnetic resonance imaging in 5,285 participants from the Adolescent Brain Cognitive Development study. We incorporated three complementary explainability methods (Integrated Gradients, Gradient Shapley Additive Explanations, and Occlusion) to interpret model behavior. The framework outperformed existing approaches, achieving Pearson correlations of 0.44, 0.58, and 0.56 for fluid, crystallized, and total intelligence, respectively, corresponding to predictive improvements of 6 to 9 percent. All three explainability methods produced near-identical feature rankings (pairwise rank correlations greater than 0.99). Consensus maps revealed a dual-layered functional architecture where primary predictive hubs localized within canonical systems, while the strongest global predictive pathways frequently bypassed these hubs through distributed, long-range relay connections. These findings suggest that intelligence emerges from the interaction between localized computational hubs and distributed communication pathways. Ultimately, these normative network architectures provide clinical reference maps to detect individual deviations, supporting earlier diagnosis, cognitive subtype stratification, and treatment monitoring in atypical neurodevelopment.
Figures & tables
Fold
Split
Subjects
Males
Females
Age (months)
Gf
Gc
Gt
1
Train
3758
1821
1936
119.86 ± 7.50
93.02 ± 10.09
87.23 ± 6.67
87.60 ± 8.52
Validation
470
239
231
119.77 ± 7.46
93.69 ± 9.64
87.49 ± 6.64
88.16 ± 8.20
Test
1057
500
557
119.66 ± 7.66
93.01 ± 10.06
87.12 ± 6.56
87.54 ± 8.44
2
Train
3765
1814
1950
119.73 ± 7.53
92.96 ± 10.13
87.18 ± 6.66
87.53 ± 8.56
Validation
463
250
213
120.06 ± 7.48
92.67 ± 10.18
87.68 ± 6.86
87.65 ± 8.58
Test
1057
496
561
119.98 ± 7.53
93.65 ± 9.67
87.21 ± 6.48
88.00 ± 8.15
TABLE I : Demographic and Cognitive Score Summary Across Five Family-Aware Cross-Validation Folds. Mean ± SD are reported.
Threshold
Gf
Gc
Gt
30%
5015.2 ± 54.3
5281.0 ± 72.8
5200.6 ± 43.1
40%
3230.0 ± 54.9
3564.4 ± 49.3
3490.2 ± 42.6
50%
2127.0 ± 20.9
2394.8 ± 10.3
2361.4 ± 53.7
60%
1366.6 ± 15.6
1610.6 ± 20.0
1585.6 ± 53.3
70%
855.0 ± 11.5
1023.2 ± 26.6
1013.8 ± 34.6
80%
468.2 ± 19.9
599.0 ± 21.6
582.2 ± 25.5
TABLE II : Average Number of Stable Features Retained Across 5 Folds by Consensus Threshold. Mean ± SD are reported.
Fig. 1 : Overview of the proposed methodology. Resting-state networks are constructed from 352 ROIs (333 cortical, 19 subcortical), yielding 61,776 static Functional Connectivity edges and 352 temporal variance features. Following family-aware stratification, bootstrapped Ridge consensus masking (50% threshold) reduces the feature space to approximately 2,100–2,400 stable features. The SPRN predicts cognitive scores through learned residual projections across descending latent dimensions (192, 96, 48, 24) with Gaussian noise augmentation, multi-level dropout ( p=0.758 ), Batch Normalization, and GELU activations. Covariates are incorporated via late fusion to prevent confounding of neural representations.
Target
SPRN Configuration
R2↑
r ↑
MAE ↓
MSE ↓
Gf
SPRN (Proposed)
0.1906 ± 0.0175
0.4421 ± 0.0198
7.1437 ± 0.0850
81.5946 ± 1.7941
– without Variance Data
0.1899 ± 0.0233
0.4412 ± 0.0269
7.1494 ± 0.0950
81.6464 ± 1.7613
– without Residual
0.1539 ± 0.0487
0.4041 ± 0.0613
7.2739 ± 0.1937
85.3054 ± 5.0049
– Covariates Only
0.1233 ± 0.0222
0.3560 ± 0.0310
7.4076 ± 0.0450
88.3668 ± 1.8614
Gc
SPRN (Proposed)
0.3361 ± 0.0250
0.5833 ± 0.0195
4.2274 ± 0.1878
29.2638 ± 2.8185
– without Variance Data
0.3358 ± 0.0237
0.5818 ± 0.0203
4.2278 ± 0.1955
29.2777 ± 2.7990
TABLE III : Ablation Study on Architectural Components of Sparse Projected Residual Networks. Mean ± SD across 5 Folds is reported. Bold indicates best per target.
Target
Bootstrap Selection Threshold
R2↑
r ↑
MAE ↓
MSE ↓
Gf
30% Consensus
0.1822 ± 0.0178
0.4342 ± 0.0163
7.1658 ± 0.0886
82.4343 ± 1.4780
40% Consensus
0.1915 ± 0.0220
0.4416 ± 0.0234
7.1276 ± 0.0468
81.4923 ± 1.5167
50% Consensus (Proposed)
0.1906 ± 0.0175
0.4421 ± 0.0198
7.1437 ± 0.0850
81.5946 ± 1.7941
60% Consensus
0.1948 ± 0.0215
0.4480 ± 0.0208
7.1310 ± 0.0848
81.1674 ± 1.9071
70% Consensus
0.1912 ± 0.0246
0.4423 ± 0.0290
7.1330 ± 0.1068
81.5256 ± 2.2796
80% Consensus
0.1879 ± 0.0253
0.4379 ± 0.0293
7.1365 ± 0.0905
81.8505 ± 1.8591
TABLE IV : Sensitivity Analysis of Bootstrapped Feature Selection Thresholds on SPRN Performance. Mean ± SD across 5 Folds is reported.
Target
Method
R2↑
r ↑
MAE ↓
MSE ↓
Gf
Ridge Regression
0.1028 ± 0.0279
0.3684 ± 0.0243
7.5259 ± 0.1298
90.4258 ± 2.1422
Lasso Regression
-0.0087 ± 0.0055
0.0000 ± 0.0000
7.9626 ± 0.1329
101.7041 ± 1.8196
ElasticNet
-0.1361 ± 0.0386
0.3061 ± 0.0255
8.4998 ± 0.1611
114.5058 ± 3.1759
Random Forest
0.1256 ± 0.0136
0.3688 ± 0.0187
7.4148 ± 0.0821
88.1493 ± 1.6804
Gradient Boosting
0.1393 ± 0.0098
0.3811 ± 0.0105
7.3559 ± 0.0760
86.7708 ± 1.0400
Standard GCN
0.1289 ± 0.0192
0.3625 ± 0.0258
7.3879 ± 0.0597
87.8054 ± 1.6192
TABLE V : Comparison of Predictive Performance Across Methodological Families. Mean ± SD across 5 Folds is reported.
Study
Model Architecture
Modality
Gf(r)
Gc(r)
Gt(r)
Huang et al. (2022) [ 17 ]
ST-DAG-Att
rs-fMRI
0.288
-
-
Li et al. (2023) [ 22 ]
Bi-LSTM (Dynamic FC)
rs-fMRI (Rest Only)
0.408
0.536
0.529
Xia et al. (2023) [ 37 ]
ML-Joint-Att
rs-fMRI
0.298
0.391
-
Thapaliya et al. (2025) [ 34 ]
BrainRGIN
rs-fMRI
0.230
0.300
0.310
This Study
SPRN (Proposed)
rs-fMRI
0.442
0.583
0.562
TABLE VI : State-of-the-Art Comparison of Intelligence Prediction using rs-fMRI on the ABCD Dataset.
Fig. 2 : XAI Consensus visualization of neuroanatomical drivers for intelligence prediction. Left panels (a, c, e): Top 10 hubs (nodes) and their strongest inter-connections. Right panels (b, d, f): Top 10 global edges across the whole brain. Color intensity reflects attribution magnitude. Panels correspond to Gf (a, b), Gc (c, d), and Gt (e, f).
Cognitive Target
Explainer Pair
Spearman ρ
Kendall τ
Pearson r
Jaccard (Top 100)
Gf
IG vs. GradientSHAP
0.9998
0.9874
0.9999
0.9802
IG vs. Occlusion
0.9995
0.9857
0.9997
0.9802
GradientSHAP vs. Occlusion
0.9993
0.9809
0.9996
0.9608
Gc
IG vs. GradientSHAP
0.9998
0.9883
0.9999
0.9802
IG vs. Occlusion
0.9992
0.9829
0.9996
0.9802
GradientSHAP vs. Occlusion
0.9990
0.9793
0.9995
0.9802
TABLE VII : Multi-Algorithm Convergence Analysis of XAI Feature Attributions.
Department of Computer Science Emory University Atlanta, Georgia, USA · Department of Radiology and Imaging Sciences Computational NeuroImaging & Neuroscience Lab, Emory University Atlanta, Georgia, USA · Department of Neurology Emory University School of Medicine Atlanta, Georgia, USA