(A) During the maintenance period (a period of 2,000 ms prior to target onset), high-gamma augmentation in the left pre-central region was greater in high-load trials compared to low-load trials (mean percent changes in high-gamma amplitude: 0.9% vs 5.8%; standard error bars presented). (B) During the scanning period (a period of 750 ms following target onset), high-gamma augmentations in the left superior-temporal (16.9% vs 15.0%) and post-central regions (3.0% vs 0.0%) were rather smaller in high-load trials compared to low-load trials. *: uncorrected p-values, which survived the Bonferroni correction for six ROIs, are presented. #: gyrus showing significant augmentation of high-gamma activity70–110Hz averaged within the maintenance and scanning periods, respectively, compared to that during the reference period (studentized bootstrap test).