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. Author manuscript; available in PMC: 2014 Feb 20.
Published in final edited form as: Dis Colon Rectum. 2010 Jul;53(7):1047–1054. doi: 10.1007/DCR.0b013e3181dcb2d6

Figure 1.

Figure 1

An example of the sensorimotor reflex (SMR). Three consecutive sets of phasic rectal balloon distensions in one subject are shown. In the first distension, there is an increase in rectal pressure (p1) with transient reflex relaxation of anal sphincter pressure (p3), demonstrating the RAIR. During the second distension a transient reflex contraction of the external anal sphincter – the recto-anal contractile reflex (RACR) is seen. In the third sequence, in addition to the RAIR and RACR, the subject reported a desire to defecate and simultaneously an anal contractile response is seen overlying the anal relaxation. Reproduced with permission from Dis Colon Rectum 2007; 50: 1639-1646.