Cooperative and Competitive Functional Connectivity Based on Improved Ising Model

Abstract

As a highly interconnected complex network system, the brain exhibits changes in interactions due to common brain disorders. Studying changes in brain network interactions can help us quantitatively analyze functional network patterns and changes in these patterns that are linked to brain disorders. However, relationships between brain regions estimated by most current approaches use a single connectivity that does not fully reflect multiple interactions. Here, we propose a novel functional connectivity (FC) construction method, which can estimate both cooperative and competitive (C-C) relationships between the same regions of interest (ROIs) through improved Ising model. We redefine the Ising dynamic equation to represent pairwise interactions from single to C-C relationships. Results show that the estimated C-C connectivities are normally distributed, with intra-subjects’ (n=970) similarity being consistently and significantly higher than inter-subjects’ similarity across datasets. C-C FCs between occipital, parietal, temporal cortex and the limbic system of schizophrenia (SZ, n=178) are more competitive, while healthy control (HC, n=219) tends to be more cooperative. Group differences in C-C patterns between SZ and HC show significant differences in frontal, parietal and occipital regions. The proposed C-C approach provide new insights into the brain dysfunction in SZ, which can also be applied to investigate other brain disorders.