Fig. 4: Alterations in insula activity before and after neurofeedback.

a Mean resting-state insula activity before (pre) and after (post) the upmodulation (blue) and downmodulation (red) training are shown. Paired t-tests were conducted to compare pre and post activity levels within each training condition. b Differences in insula activity (post - pre) for the upmodulation (blue) and downmodulation (red) conditions are shown. A paired t-test was conducted to compare these differences between the two conditions. All the data were analyzed by two-tailed paired Student’s t tests with Bonferroni correction. Asterisks (*) denote statistically significant differences, *p < 0.05, **p < 0.01. In the boxplots, dots represent individual data points, centrelines represent medians, box limits represent lower and upper quartiles, whiskers represent 1.5 times the interquartile range, and circles represent outliers.