recording electrical signals in the arm's nerves, this heroic research discovers the limits of touch sensation in the fingertip. at just 0.4mm our sensitivity matches the width of the grooves in our fingerprints  

original article: Jarocka et al., 2021 (Journal of Neuroscience), reported in: The New Scientist by Christa Leste-Lasserre on 15th March 2021 & The Guardian by Nicola Davis on 15th April 2021 & Twitter by Andrew Pruszynski on 16th March 2021

this story was in episode 8 #fingerprint #touch #maps #microneurography

the error bar says

the New Scientist & the Guardian report on a paper investigating the nervous system's processing of fine details by the human fingertip

12 adults sat in a dentists chair, their right arm Velcro'd down, a fingertip glued to a plastic frame, a robot probing their skin with raised dots & a wire needle plunged into their upper arm

this sophisticated form of torture is called microneurography. only a handful of scientists in the world can do it. experimenters sit for hours next to their subject's arm, prodding & poking & wiggling a wire in their skin until a single nerve fibre is found

when, or more likely, if they can do that, the experiment begins. from their 12 'volunteers' they recorded 34 single nerve cells, each one responding to touches on the fingertip

changing the speed & direction of the touches, mapping the skin's ridges & systematically testing the nerve responses produced beautiful fingertip maps & clear conclusions: the fingertip ridges give us sensitivity to tactile details as small as 0.4mm

can we really feel the groove?

yes. this is a rare win-win for brain science & brain science communication - this gorgeous paper is well-reported by both media sources

the expertise, equipment, skill & patience required to do this kind of work is Herculean. it rightly deters weaker mortals from attempting it. the data obtained & the maps of the hand's nervous system that it provides are almost mythological treasures

on the stats side, i should add that phrases like 'cross-correlation', 'data shuffling' & 'Fisher's transformation' all suggest that this is proper science done properly by proper scientists


a painstaking investigation of the spatial response properties of the nerves in the human fingertip reveals beautiful maps of the exquisite sensitivity of our skin


The New Scientist: fact - scientific story reported well

The Guardian: fact - scientific story reported well

Twitter: fact - scientific story reported well