How to Integrate Data from Multiple Biological Layers in Mental Health?

Abstract

Integrating information from multiple biological layers is a key approach to unraveling the complexities of the human brain, with its multiple overlapping structural and functional subsystems operating at widely different temporal and spatial scales. Moreover, it has true potential to positively impact mental health patients through early diagnosis and individualized treatment. This chapter lays out a succession of approaches to synergistic fusion of multimodal brain imaging data, with a special focus on blind source separation (BSS) and deep learning (DL) methods. Firstly, a broad unified description of the BSS field is introduced, serving as a theoretical backbone for the chapter. Complementary to that, a detailed case study of three different applications of joint independent component analysis (jICA) provides both a reference guide on data fusion and a bridge into more advanced BSS methods. Various advanced BSS methods such as multiset canonical correlation analysis (mCCA), multi-way partial least squares (N-PLS), independent vector analysis (IVA) and Parallel ICA are then reviewed and discussed in terms of their strengths and limitations. Finally, DL methods are introduced, focusing on three important applications: classification utilizing strategies for multimodal data augmentation, embedding of learned representations in order to reveal disease severity spectra, and multimodal tissue segmentation.