Skin – the largest organ in the human body – surrounds us from head to toe, allowing us to touch, feel and interact with the outside world. But one part of that organ is more interesting to rub than any other part.
A new study has revealed just how infectious the sensory neurons are in our fingers: As it turned out, we can detect rubbing on a minuscule scale of one fingerprint.
“You would expect one papillary spine to be involved, but it has not been shown [before], “Said Ewa Jarocka, co – author of the study from Umeå University in Sweden The Keeper.
Sensory neurons are attached to dotted receptors just below the surface of the skin, allowing us to detect rubbing, shaking, pressure, pain and much more. In our own hands there are tens of thousands of these neurons, each with receptors on a small surface area of the skin, called a receptor field.
To map these fields, the researchers put down the arms of 12 healthy people and glued their nails to plastic guards to make sure they could not move. A machine then wraps tiny cones, 0.4 millimeters across 7 mm apart over the skin (you can see what that looks like below) and the team recorded the response of each neuron using electricity in arms of the participants.
The situation. (Jarocka et al., J. Neurosci, 2021)
In particular, they mapped the more sensitive zones – called subfields – within these receptor domains.
By measuring the sensory neuron detection areas and mapping them on the fingerprint, the team found that the width of the detection area was equal to the width of one fingerprint spine.
These sub-areas also did not move when the machine moved the dots faster or slower, or when they changed directions, suggesting that these sensitive areas are anchored to the fingerprint ridges. themselves.
“We report that the sensitivity of the subfield arrangement for both neuron types averages a spatial duration of 0.44 mm and provides evidence that subfield spatial selectivity arises because the receptor organ is associated. measures mechanical events confined to a single papillary spine, “the researchers write in their new paper.
Predicted catch areas on fingerprints. (Jarocka et al., J. Neurosci, 2021)
Interestingly, this is the first study that shows that our fingerprint ridges help us feel the world around us more accurately.
“We all have these many hotspots, and each one fits a 0.4 millimeter detail, which is the approximate width of the [fingerprint] back, “Jarocka said New scientist.
“Then our brain gets all that information. This really explains how it’s possible that we’re so dexterous and have such high sensitivity in fingers.”
The research was published in The Journal of Neuroscience.