A Telescopic Independent Component Analysis on Functional Magnetic Resonance Imaging Data Set
Brain function can be modeled as the dynamic interactions between functional sources at different spatial scales, and each spatial scale can contain its functional sources with unique information, thus using a single scale may provide an incomplete view of brain function. This paper introduces a novel approach, termed "Telescopic independent component analysis (ICA)," designed to construct spatial functional hierarchies and estimate functional sources across multiple spatial scales using fMRI data. The method employs a recursive ICA strategy, leveraging information from a larger network to guide the extraction of information about smaller networks. We apply our model to study the default mode network (DMN) and evaluate the difference between healthy people and individuals with schizophrenia. We show that the telescopic ICA approach can detect the spatial hierarchy of DMN and their associated group differences between cohorts that may not be captured if we focus on a single-scale ICA. In sum, our proposed approach represents a promising new tool for studying functional sources.