Methodological considerations for quantifying brain asymmetry using neuroimaging techniques

Structural and functional asymmetries are crucial for understanding the relationship between the left and right hemispheres of the human brain. Quantifying brain asymmetry or lateralization represents a fundamental methodological choice in this field, and approaches vary considerably across studies. This review aims to briefly summarize and discuss methodological considerations for quantifying brain asymmetry across different neuroimaging techniques and research contexts. We illustrate how the definition of specific homotopic units serves as a prerequisite, how the degree of hemispheric asymmetry between these units is quantified using lateralization index formulas, and how the application of these lateralization indices requires careful consideration.