Fig. 3: Modulation of insula activity during neurofeedback training.

a Temporal dynamics of mean standardized insula activity during upregulation (blue) and downregulation (red) conditions. The solid lines represent the mean activity across subjects, and the shaded areas indicate the standard error of the mean (SEM). All curves in this figure have been smoothed using a 100-point (20-s) moving average to clearly illustrate the neurofeedback modulation trends. The vertical dashed line at 600 s marks a brief pause between two training sessions. b The boxplot compares the mean insula activity during the entire training process for each subject under the upmodulation and downmodulation conditions. Insula activity during upmodulation training was significantly greater than that during downmodulation training (blue for upmodulation training; red for downmodulation training). Two-tailed paired Student’s t test, *p < 0.05. In the boxplots, centerlines represent medians, the box limits represent the lower and upper quartiles, the whiskers represent 1.5 times the interquartile range, and the circles represent outliers.