Introduction Faecal incontinence (FI) may follow pudendal nerve injury sustained during childbirth. Sacral neuromodulation (SNM) is a treatment option for FI, when conservative treatment has failed. The mechanism of action of SNM is yet unclear. However SNM may augment anal sensation via afferent somatosensory fibres, as small sensory fibres are more susceptible to damage than the larger motor fibres. This study investigates, how fore paw, hind paw and anal canal evoked cortical potentials (EPs) are affected by SNM in an animal model. Methods Six female virgin Wistar rats (body mass: 230g-270g) were used. Experiments were carried out in accordance to protocols approved by the UCD Animal Ethics Research Committee and licenced by the Irish Department of Health and Children. Experiments were performed under urethane anaesthesia (1.5g.kg-1, i.p.) and vital signs were stable throughout. A craniotomy was performed over the right primary somatosensory cortex. A 32 channel multi-electrode array, placed extra-durally, recorded EPs created by electrical anal canal stimulation, left tibial nerve stimulation and left median nerve stimulation. SNM was performed utilizing a concentric needle electrode placed in the left first sacral foramen. Stimulation parameters were 10Hz, 15V and 1ms pulse duration for 3min. EPs before and 10 and 40min after SNM were compared for each location. Values are expressed as mean ± sem; the criterion for statistical significance was P<0.05. Results EPs consisted of one upward deflection and a small less marked downward deflection (Figure 1). Anal canal EPs had a latency of 11.5ms±0.73ms and amplitude of 18.8μV±3.56μV; tibial nerve EPs 9.0ms±0.42ms and 32.6μV±5.17μV; median nerve EPs 8.4ms±1.1ms and 21.5μV±3.79μV. SNM induced an increase in the maximal amplitude of 50% in anal canal and tibial nerve EPs, but not in median nerve EPs (Figure 2). A two-factor (location and time) repeated measures ANOVA showed that this result was highly significant (location factor: P<0.0001). Conclusions S1 neuromodulation causes facilitation of afferent fibre input of the same spinal segmental level but not higher segmental level. This study provides evidence that SNM selectively restores sacral inputs and may improve cortical awareness of the anorectum. The finding that a limb nerve input is also augmented may serve as a surrogate marker of the efficacy of SNM. This fact also suggests that percutaneous posterior tibial nerve stimulation, a novel treatment for FI, may share a similar mechanism to SNM.