Structural-Functional Brain Connectivity Generation via Multimodal Hypergraph-based Flow Matching

2026-10-01

AI Summary

This study addresses the scarcity of brain structural-functional connectivity (SC-FC) data and the limitations of existing methods that capture only pairwise interactions and generate modalities independently, thereby losing higher-order relationships. To this end, we propose the MHG-FM framework, which constructs a multimodal hypergraph to transcend traditional pairwise constraints. The method achieves cross-modal fusion through hypergraph neural network encoding and bidirectional cross-attention, while integrating variational autoencoders with conditional flow matching for joint generation and cross-modal translation. Evaluated on the HCP-YA dataset, MHG-FM outperforms state-of-the-art baselines in reconstruction quality, topological preservation, and distributional similarity, while achieving approximately an 8-fold increase in sampling speed compared to diffusion models.

Abstract

Structural connectivity (SC) and functional connectivity (FC) provide complementary information on interactions between brain regions and are widely used in neuroimaging studies of neuropsychiatric disorders. Generative modelling can alleviate the scarcity of large-scale paired SC-FC data, but existing approaches typically use pairwise graphs that capture only dyadic interactions and often generate SC and FC independently, limiting preservation of higher-order structure-function relationships. We propose a Multimodal Hypergraph Flow Matching (MHG-FM) framework for joint SC-FC connectivity generation and cross-modal translation. MHG-FM constructs modality-specific hypergraphs, learns higher-order representations with Hypergraph Neural Network (HGNN) encoders, and performs bidirectional cross-modal fusion using Dual Cross-Attention (DCA). A variational autoencoder maps the fused representations to a compact latent space, where conditional flow matching enables connectivity synthesis and multimodal translation via latent transport. Experiments on the Human Connectome Project Young Adult (HCP-YA) dataset show that MHG-FM outperforms several state-of-the-art baselines in reconstruction quality, topology preservation, distributional similarity, and SC-FC coupling, while achieving approximately 8x faster sampling than a matched diffusion backbone.

Problem

• Structural Connectivity
• Functional Connectivity
• Generative Modeling
• Higher-order Relationships
• Cross-modal Translation

Innovation

• Multimodal Hypergraph
• Flow Matching
• Brain Connectivity Generation
• Cross-modal Translation
• Hypergraph Neural Network