It remains hidden from view most of the time

Dec 9, 2009 10:52 GMT  ·  By

Scientist have suspected for a long time that we may be receiving extra information from within our bodies, in addition to the data we receive from our nervous system. The latter allows us to touch and sense objects, and is made possible by countless free nerve endings, right underneath the skin. But now, experts say that they have finally discovered a new sensory system, which usually remains out of view. In a recent study, conducted on two test subjects, experts have discovered that the new sensory system is hidden in the blood vessels and sweat glands, LiveScience reports.

“It's almost like hearing the subtle sound of a single instrument in the midst of a symphony. It is only when we shift focus away from the nerve endings associated with normal skin sensation that we can appreciate the sensation hidden in the background,” Albany Medical College Neuroscience Professor Frank Rice says. The expert is also the senior author of a new scientific study detailing the finds, which appears in the December 15 issue of the respected scientific journal Pain. The new discovery comes on the heels of another exciting one, which showed that a person's skin – the largest organ in the body – could also hear certain frequencies.

The two patients made for ideal test subjects because they were born with a very rare condition known as congenital insensitivity to pain. This meant that they felt little to no pain, regardless of what they did. Some symptoms that individuals diagnosed with this condition have include an excessively dry skin, engaging in self-mutilation without realizing it, as well as severe mental handicaps. “Curiously, our conventional tests with sensitive instruments revealed that all their skin sensation was severely impaired, including their response to different temperatures and mechanical contact,” University of Liverpool scientist Dr. David Bowsher adds.

The study researcher is a Honorary Senior Research Fellow at the UL-based Pain Research Institute. “For all intents and purposes, they had adequate sensation for daily living and could tell what is warm and cold, what is touching them, and what is rough and smooth,” he adds. The expert made skin biopsies – harvested small samples – and then took them to Rice's lab, where the latter analyzed the nerve endings right under the surface of the skin. “Much to our surprise, the skin we received from England lacked all the nerve endings that we normally associated with skin sensation. So how were these individuals feeling anything?” Rice says.

The team eventually found the source, as their work revealed nerve endings on small blood vessels and sweat glands in the skin samples. Rice believes that the brains of the two patients learned to use these endings, and were drawing the information they needed based on them. “For many years, my colleagues and I have detected different types of nerve endings on tiny blood vessels and sweat glands, which we assumed were simply regulating blood flow and sweating. We didn't think they could contribute to conscious sensation. However, while all the other sensory endings were missing in this unusual skin, the blood vessels and sweat glands still had the normal types of nerve endings,” Rice concludes.