Sense of touch could be thanks to “hair follicles in our skin”
Rough with the smooth: Our sense of touch may actually be down to our hair follicles
Our sense of touch could be down to hair follicles in our skin, scientists say.
Touch is the least understood of our senses, but new research suggests specialised neurons in hair follicles each work as individual sensory organs, tuned to register different types of touch.
In mice, the team found that each follicle sends a single message that joins with others in the spinal cord and together the impulses are decoded by the brain.
It is the network of neurons working together that allows us to distinguish between different sensations such as rough and smooth, reports journal Cell.
Dr David Ginty of The Johns Hopkins University School of Medicine, said: “We can now begin to appreciate how these hair follicles and associated neurons are organised relative to one another.
“That organisation enables us to think about how mechanosensory information is integrated and processed for the perception of touch.”
In the mice the researchers found three follicles in particular that made up their coats, and discovered distinct populations of low-threshold mechanoreceptors (LTMRs).
These LTMRs are the signals that connect the spinal cord to the skin and in humans can be more than a metre long.
Dr Ginty found that each hair follicle type included a distinct combination of mechanosensory endings. These send signals to the spinal cord in a series of narrow columns, which each gathers input from a particular area of the skin.
He points out that because humans don”t have fur it”s not clear whether the neurons in the mice depend on the hair itself or the scaffold provided by the follicle.
But he said: “We now they have the genetic access we need to tinker with each LTMR subtype one by one, turning them on or off at will and seeing what happens to the brain and to behaviour.”
Intriguingly, one of the LTMR types under study is implicated as “pleasure neurons” in people, Ginty notes.