Kayako Matsuo1, Annabel S.-H. Chen2,
Wen-Yih Isaac Tseng1
1Center for Optoelectronic
Biomedicine, National Taiwan University College of Medicine, Taipei, Taiwan; 2Division
of Psychology, School of Humanities & Social Sciences, Nanyang
Technological University, Singapore
Laterality index (LI) is often applied in functional magnetic resonance imaging (fMRI) studies to determine functional hemispheric lateralization. However, conventional LI methods could suffer from an outlier bias if t-values were extreme for a small number of voxels. We developed an improved method to calculate LI for fMRI called AveLI. This method considers laterality of activation at each and every t-value threshold for the task (thus this index is not limited by over stringent thresholds), and allows an intuitive comprehension of overall asymmetry. We examined the feasibility and reproducibility of AveLI by applying it to two fMRI language tasks.
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