Even with our eyes closed, we can distinguish a pair of jeans, rough bark, or a lover’s caress through our sense of touch. The sense of touch is an important way to perceive the world around us. A new study has found that the secret to such a sensitive sense of touch in humans is hidden between fingerprints.
Scientists have discovered that fingerprints are unique to each person, and they are now widely used for identification purposes. This new study finds that fingerprints have other, even more amazing uses: sensitive neuronal receptors that follow the fingerprint’s pattern and are located underneath those patterns.
Tactile neurons attached to the receptors are located under our skin, allowing us to experience a variety of sensations such as touch, vibration, pressure, and pain. Scientists know that in the hands alone, there are tens of thousands of neurons, each attached to a receptor responsible for a specific range of skin. Researchers refer to the area of the skin that each receptor is in charge of as the “receptive field.
Scientists at Umeå University in Sweden aimed to map the distribution of these receptive fields. They asked 12 healthy people between the ages of 20 and 30, including six men and six women, to participate in the experiment. The researchers immobilized their hands to prevent sliding, and then used a roller device to probe the tactile receptors of the fingers.
The roller was densely packed with small spiky cone bumps, each only 0.4 mm in diameter and about 0.5 mm high, with each bump spaced about 7 mm apart. The researchers used electrodes on the subject’s arm to record the response of each neuron.
By calculating the area of skin each sensing neuron was in charge of and corresponding them to the fingerprint, the team found that the width of these sensing areas was exactly equal to the width of the ridged bumps of the fingerprint.
And these receptive fields do not move with the speed and direction of the roller roll, which the researchers believe means that these sensitive receptor areas are fixed to the fingerprint’s spiral ridge-like pattern. The researchers say this study is the first to find that the ridges in fingerprints also help us accurately perceive our surroundings.
The study was published March 15 in the Journal of Neuroscience.
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