Uncovering Intrinsic Connectional Architecture of Functional Networks in Awake Rat Brain

Abstract

Intrinsic connectional architecture of the brain is a crucial element in understanding the governing principle of brain organization. To date, enormous effort has been focused on addressing this issue in humans by combining resting-state functional magnetic resonance imaging (rsfMRI) with other techniques. However, this research area is significantly underexplored in animals, perhaps due to confounding effects of anesthetic agents used in most animal experiments on functional connectivity. To bridge this gap, we have systematically investigated the intrinsic connectional architecture in the rodent brain by using a previously established awake animal imaging model. First, group independent component analysis was applied to the rsfMRI data to extract elementary functional clusters of the brain. The connectional relationships between these clusters evaluated by partial correlation analysis were then used to construct a graph of whole-brain neural network. This network exhibited typical features of small-worldness and strong community structures as shown in the human brain. Finally, the whole-brain network was segregated into community structures using a graph-based analysis. The results of this work provided a functional ‘atlas’ of intrinsic connectional architecture of the rat brain at both intra- and inter-region levels. More importantly, the current work revealed that functional networks in rats are organized in a non-trivial manner and conserved fundamental topological properties as the human brain. Given the high psychopathological relevance of network organization of the brain, this study demonstrated the feasibility to study mechanisms and therapies of multiple neurological and psychiatric diseases through translational research.

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