Abstract
This study attempted to design a simultaneous measurement of BOLD signal and the diameter of the pupil based on the task load-dependent physiological response model to further characterize the brain activation. Seven healthy male subjects performed a digit category judgment task in the fMRI. The mean standardized diameter of pupil during the task blocks was z = 0.05 ± 0.76 in the low load condition; LL. In the high load condition; HL, the mean standardized diameter during task blocks was z = 0.40 ±0.64. In both conditions, significant activation was observed in the auditory and attention networks in each hemisphere. The contrast LL against HL was detected in the SPL and the IPL in each hemisphere. In addition, significant statistical correlations were observed between the variation of diameter and the task load-dependent brain activation in bilateral MFG ([BA] 46) (all p < 0.001, uncorrected). Focusing on parietal areas might be useful for detecting the individual difference on working memory in the clinical setting.
