UMEĂ…, Sweden — Fingerprints are a unique feature of every human being. No two people have the extra same sets of ridges on their hands, not even twins. While this makes them invaluable for solving crimes, a study finds these microscopic ridges also enhance the sense of touch.
Researchers from the UmeĂ¥ University say the sensory nerve cells in a finger can detect the feeling of touch with remarkable detail; on a scale of a single ridge in the person’s fingerprint.
Overall, the human hand has tens of thousands of sensory neurons in it. These cells tune in to the surface of the skin, picking up everything from vibrations, to pressure, to tactile stimuli. Until now, scientists did not know just how sensitive a single sensory neuron is.
Is the sense of touch as unique as your fingerprints?
Dr. Ewa Jarocka and a team of researchers measured the electrical activity of the neurons in human fingertips. To do this, they swept raised dots over the skin to stimulate the sense of touch. Study authors then calculated the detection areas of the neurons and mapped the results along the person’s actual fingerprints.
The results reveal the width of nerve cell detection matches the width of individual fingerprint ridges. These detection areas stayed in the same ridges regardless of the speed or direction of the stimulation. Researchers say this means these sensory neurons are anchored to the fingerprint ridges; creating a higher degree of feeling along these unique lines.
“We show that the subfields’ spatial selectivity typically corresponds to the dimension of the ridges (∼0.4 mm) and a neuron’s subfield layout is well preserved across tangential movement speeds and directions representative of natural use of the fingertips,” researchers write in their report.
The study appears in The Journal of Neuroscience.