Fig. 2

(a) Schematic Outlining Cohort and Study Design: The learning curve study design is depicted in a gray box chain format, where each box represents a day of the study. The untrained control group (orange) performed the task on the first day and again on the post-test day. The block design of expert and novice surgeons is shown in red and green boxes respectively. Note: ‘‘n’’ is number of subjects and ‘‘m’’ is number of trails performed by each subject. (b) Short-term tES Study Block Design: The vertical red box labeled “Pre/Post-test and fNIRS” indicates that these components were conducted simultaneously. The time indicated at the bottom of the block represents the duration spent on each respective component. (c) block design long-term tES study: Each small black box represents one training day. The blocks on the bottom row (red boxes) indicate the specific procedures carried out on each session on the respective day.