Reply to comment

Like many, I am still unable to grasp the role of the I function and how an individual can walk on hot coals without feeling pain. I found this interesting article online (http://www.guardian.co.uk/society/2006/dec/14/health.pakistan) that describes how a young boy from Pakistan could walk on hot coals and feel no pain. The scientists in the investigation looked at three families related to the child and found that none had experienced pain at any point in their lives. After extensive genetic tests, the scientists concluded that the boy and the other individuals all had an extremely unusual mutation in a single gene. The defect in this gene, SCN9A, disrupts the flow of sodium ions into specific neurons that sense damage. The mutation causes the first stage of the electrical signal to be lost, so the signal is unable to reach the brain. Could this be an explanation for the lack of an "I" function?