Fingerprints are wired to detect touch at the level of a single fingerprint ridge

Embargoed until: Publicly released: 2021-03-16 05:00

International

Credit: Jarocka et al, JNeurosci

Look closely at your fingertips. See those tiny little ridges? It turns out that your fingers are so sensitive they can detect touch on the scale of one of those tiny fingerprint ridges, according to Swedish and Canadian research. The human hand has an amazing sense of touch, but until now the exact sensitivity of a single sensory nerve was not known. To measure each nerves sensitivity, the researchers swept raised dots over the skin of the fingertips and measured the electrical activity of the sensory nerves. They calculated the areas of the skin each sensory nerve detects and found it matched the width of a single fingerprint ridge. The authors say this helps explain how humans have such a sensitive and accurate sense of touch.

Media release

From: Society for Neuroscience

Fingerprints Enhance Our Sense of Touch

Sensory neurons in the finger can detect touch on the scale of a single fingerprint ridge

Fingerprints may be more useful to us than helping us nab criminal suspects: they also improve our sense of touch. Sensory neurons in the finger can detect touch on the scale of a single fingerprint ridge, according to new research published in JNeurosci.

The hand contains tens of thousands of sensory neurons. Each neuron tunes in to a small surface area on the skin — a receptive field — and detects touch, vibration, pressure, and other tactile stimuli. The human hand possesses a refined sense of touch, but the exact sensitivity of a single sensory neuron has not been studied before.

To address this, Jarocka et al. measured the electrical activity of the sensory neurons in human fingertips when they stimulated with raised dots swept over the skin. The research team calculated the detection areas of the sensory neurons and mapped them onto the fingerprints. The width of the detection areas matched the width of a single fingerprint ridge. These areas stayed on the same fingerprint ridges during different scanning speeds and directions, indicating that they are anchored to the fingerprint ridges. The overlap of receptive fields with small detection areas explains how humans have such a sensitive and accurate sense of touch.

Journal/
conference: JNeurosci

Organisation/s: Umeå University, Sweden

Funder: This work was supported by the Swedish Research Council (Projects 22209 and 01635) and a Long-Term Fellowship from the Human Frontier Science Program (J.A.P).

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