Our fingernails know us so well that sometimes Tell us about your health. But there are surprisingly many things we don’t know about them, one of which is that they are incredibly sensitive to even the slightest touch.
One study found that people can distinguish where a touch was applied to their fingernails just as accurately as they can distinguish the feel of their fingertips.
“It’s not just that people can perceive the sensation of touch on the tip of their fingernails.” Write A new paper has been published by Matthew Longo, a neuroscientist at University College London.
“People can tell exactly which part of their nail is being stimulated.”
Longo conducted two experiments, recruiting 38 participants between the ages of 18 and 60, to investigate the sensory abilities of fingernails.
Half of the volunteers were asked to mark on a photograph of their fingernails or fingertips the location of tactile stimuli they could not see but felt on their fingers.
The other half were asked to do the same thing, but their fingers and nails touched the filament instead of the stick. This allowed them to A small amount of pressure continuously It applies every time.
To generalize beyond a specific finger, the first experiment was performed with the middle finger and the second experiment with the thumb.
“The localization performance of the fingernails was above chance level for all participants tested and was broadly similar to the performance of the fingertip itself,” Longo said. establish.
Despite the fact that there are no tactile receptors at the tip of the fingernail, our skin does. MechanoreceptorIt responds to various stimuli such as temperature and pressure.
Some pressure receptors are activated by very light pressure, but others require a stronger shock before they send an immediate warning signal through the nerves about a physical presence.
But we can also localize contact with a stick held in our hand, such as a cane used by a blind person, so scientists suspect that a similar mechanism might be involved at the far end of our fingernails.
“In both cases, the exact location of the stimulus is detected despite the absence of tactile receptors within the stimulated surface itself.” explain Longo.
Pacinian corpuscle Mechanoreceptors are located deep in the second to last layer of the skin. dermis. These nerve endings detect vibration patterns over large areas of our skin, allowing us to understand the tactile location of tools.
Longo believes that these tactile receptors may be encoding sensory information in the fingernails, even though they are not found under the fingernails.
It is not yet known why our fingernails are so sensitive, but it is possible that this sensorimotor function plays a role in our species’ extraordinary dexterity and the special tactile sensitivity recently discovered around hair follicles.
“It will also be interesting to see whether this ability is limited to fingernails, or whether tactile stimuli can also be precisely localized to the toenails.” proposal Longo.
This study Proceedings of the Royal Society B.
