Predicting Biomedical Interactions with Bayesian inference over Graph Convolutional Network Structures
1. The authors identify a persistent bottleneck in graph neural network (GNN) application to biological networks: selecting the optimal number of graph‑convolution (GC) layers. Too few layers miss higher‑order interactions, while too many cause over‑smoothing and loss of predictive power.
2. To solve this, they introduce a Bayesian model‑selection framework that jointly infers the appropriate depth of a GC encoder and applies dropout regularization, allowing the network to adapt its complexity directly from the data rather than relying on heuristic layer counts.
3. The depth is modeled as a stochastic process via a beta process over layers, inducing layer‑wise activation probabilities. A conjugate Bernoulli process then gates neuron activations, effectively creating an encoder capable of an infinite number of layers in theory while only activating a sparse subset in practice.
4. For reconstructing interactions, a bilinear decoder maps node representations into edge probabilities. This end‑to‑end encoder‑decoder architecture eliminates the need for separate embedding and classifier stages.
5. The authors employ structured stochastic variational inference to approximate the intractable marginal likelihood, using a concrete Bernoulli relaxation for efficient gradient‑based optimization of both depth and dropout parameters.
6. Across four publicly available biomedical interaction datasets (DTI, DDI, PPI, GDI), the Bayesian GCN outperforms DeepWalk, node2vec, L3, VGAE, and fixed‑depth GCNs, achieving gains in AUPRC ranging from ~2–20% and AUROC improvements up to ~3%.
7. The framework also delivers better calibrated predictions: Brier scores are consistently lower than those of a fixed‑depth GCN, indicating more reliable confidence estimates for interaction probabilities.
8. Robustness tests show the method maintains high performance even on highly sparse networks, thanks to its dynamic neuron activation that scales with available training edges, whereas a fixed‑depth GCN activates all neurons regardless of sparsity.
9. Visualizing drug embeddings with t‑SNE reveals that the Bayesian GCN produces clearer, well‑separated clusters for drug categories, suggesting that the learned representations capture pharmacological similarities more faithfully than a conventional GCN.
10. Finally, the model’s novel predictions—both drug‑drug and gene‑disease associations—receive higher confidence scores and are corroborated by recent literature, underscoring the practical value of the inferred depth and structure.
💻Code:
github.com/kckishan/BBGCN-LP…
📜Paper:
arxiv.org/abs/2211.13231
#GraphNeuralNetworks #BiomedicalComputing #DeepLearning #Bioinformatics #MachineLearning #ModelSelection #GraphConvolutionalNetworks #BayesianInference #DrugDiscovery #GeneDiseaseAssociations