Human fingertips have several types of sensory neurons that are responsible for relaying touch signals to the central nervous system. Scientists have long believed these neurons followed a linear path to the brain with a “labeled-lines” structure. But new research on mouse whiskers from Duke University reveals a surprise — at the fine scale, the sensory system’s wiring diagram doesn’t have a set pattern. And it’s probably the case that no two people’s touch sensory systems are wired exactly the same at the detailed level, according to Fan Wang, Ph.D., an associate professor of neurobiology in the Duke Medical School.
“We take our sense of touch for granted,” Wang said. “When you speak, you are not aware of the constant tactile feedback from your tongue and teeth. Without such feedback, you won’t be able to say the words correctly. When you write with a pen, you’re mostly unaware of the sensors telling you how to move it.”