Evaluation of Laterality Indices for Quantifying Hemispheric Lateralization of Resting-State Functional Connectivity Taeyoung Lee

Abstract

Introduction: The study of biological asymmetries, especially asymmetries of the cerebral hemispheres, has revealed that structural and functional differences are inherent in biological systems from animals to humans. Although numerous techniques have been devised to objectify asymmetries in the cerebrum and, more recently, to assess functional asymmetries in the cerebrum using resting-state functional magnetic resonance imaging, these methods have yet to account for false positives and the signs of functional connectivity. Methods: This study included 44 right-handed male participants without neurological disorders. Participants completed the Wechsler Abbreviated Intelligence Scale and functional magnetic resonance imaging. A functional asymmetry model of cerebral segregation and integration effects was tested for various false positives and signs of functional connectivity. Correlation analysis with cognitive function was performed using the validated model. Results: There were significant differences in brain asymmetry models depending on the level of false positives and the signs of functional connectivity. In addition, there were significant correlations between cognitive abilities related to language and spatial perception processing and brain asymmetry indices depending on the direction of false positives and functional connectivity. Discussion: This study highlights the methodological importance of validating the false positives and the signs of functional connectivity in studies of functional asymmetry in the brain using functional magnetic resonance imaging. The findings of this study will provide important insights for future research, especially on applying functional asymmetry indices derived from brain imaging signals to understand the complex operation of the human brain. Keywords: functional magnetic resonance imaging, brain asymmetry, functional connectivity, false positives, signs