Replica-Based Federated Learning with Heterogeneous Architectures for Graph Super-Resolution

Having access to brain connectomes at various resolutions is important for clinicians, as they can reveal vital information about brain anatomy and function. However, the process of deriving the graphs from magnetic resonance imaging (MRI) is computationally expensive and error-prone. Furthermore, an existing challenge in the medical domain is the small amount of data that is available, as well as privacy concerns. In this work, we propose a new federated learning framework, named RepFL. At its core, RepFL is a replica-based federated learning approach for heterogeneous models, which creates replicas of each participating client by copying its model architecture and perturbing its local training dataset. This solution enables learning from limited data with a small number of participating clients by aggregating multiple local models and diversifying the data distributions of the clients. Specifically, we apply the framework for graph super-resolution using heterogeneous model architectures. In addition, to the best of our knowledge, this is the first federated multi-resolution graph generation approach. Our experiments prove that the method outperforms other federated learning methods on the task of brain graph super-resolution. Our RepFL code is available at https://github.com/basiralab/RepFL .