Figure 1.

Rectal stimulation protocol and rectal sensation thresholds. Rectal pain stimuli (A) were given in a block design consisting of 8 balloon distensions (referred as active in the figure) of 24 seconds each separated by rest phases of 24 seconds each. The balloon inflation and deflation for each stimulus required 24 to 48 seconds and 12 seconds, respectively. (B, C) Representative box-cum-whisker plots demonstrating the defecation and pain sensation thresholds for diarrhea-predominant irritable bowel syndrome (IBS-D), constipation-predominant irritable bowel syndrome (IBS-C), and normal controls (*P < 0.05; **P < 0.005; ***P ≤ 0.001; NS, not significant). Bottom and top boundaries of boxes are 25th and 75th percentiles, respectively. Lower and upper whiskers are 5th and 95th percentiles, respectively.