This work was presented at Digestive Disease Week, Chicago, Illinois, 2009 and published as an abstract in Gastroenterology 2009; 136 A778.
A bi-directional assessment of the human brain-anorectal axis
Article first published online: 21 OCT 2010
© 2010 Blackwell Publishing Ltd
Neurogastroenterology & Motility
Volume 23, Issue 3, pages 240–e118, March 2011
How to Cite
Remes-Troche, J. M., Tantiphlachiva, K., Attaluri, A., Valestin, J., Yamada, T., Hamdy, S. and Rao, S. S. C. (2011), A bi-directional assessment of the human brain-anorectal axis. Neurogastroenterology & Motility, 23: 240–e118. doi: 10.1111/j.1365-2982.2010.01619.x
- Issue published online: 8 FEB 2011
- Article first published online: 21 OCT 2010
- Received: 26 May 2010 Accepted for publication: 22 September 2010
- anorectal sensation;
- cortical evoked potentials;
- transcranial magnetic stimulation
Background Brain-gut dysfunction has been implicated in gastrointestinal disorders but a comprehensive test of brain-gut axis is lacking. We developed and tested a novel method for assessing both afferent anorectal-brain function using cortical evoked potentials (CEP), and efferent brain-anorectal function using motor evoked potentials (MEP).
Methods Cortical evoked potentials was assessed following electrical stimulations of anus and rectum with bipolar electrodes in 26 healthy subjects. Anorectal MEPs were recorded following transcranial magnetic stimulation (TMS) over paramedian motor cortices bilaterally. Anal and rectal latencies/amplitudes for CEP and MEP responses and thresholds for first sensation and pain (mA) were analyzed and compared. Reproducibility and interobserver agreement of responses were examined.
Key Results Reproducible polyphasic rectal and anal CEPs were recorded in all subjects, without gender differences, and with negative correlation between BMI and CEP amplitude (r −0.66, P = 0.001). Transcranial magnetic stimulation evoked triphasic rectal and anal MEPs, without gender differences. Reproducibility for CEP and MEP was excellent (CV <10%). The inter-rater CV for anal and rectal MEPs was excellent (ICC 97–99), although there was inter-subject variation.
Conclusions & Inferences Combined CEP and MEP studies offer a simple, inexpensive and valid method of examining bidirectional brain-anorectal axes. This comprehensive method could provide mechanistic insights into lower gut disorders.