Our bodies have a dedicated channel for sensing only the very lightest of touches.
You were probably taught that we have five senses: sight, sound, smell, taste and touch. This is not quite right: “touch” is not a single sense, but rather several working together.
How we sense gentle touch Sensing gentle touch begins with tiny deformations of the skin due to a light brush. While they may not seem like much, these deformations generate enough force to activate sensory molecules that are found in specialised nerve endings in the skin. Our new research, led by Gary Lewin and Sampurna Chakrabarti from the Max Delbruck Center in Berlin, showed the force sensor ELKIN1 is necessary for us to detect very gentle touch.
ELKIN1 is the second touch-receptor molecule discovered in sensory neurons. The first was found in 2010 by Ardem Patapoutian, who was later awarded the Nobel Prize for the work. PIEZO2 is involved in sensing gentle touch, as well as a sense known as “proprioception”. Proprioception is the sense of where our limbs are in space that helps us regulate our movements.
With team members at the University of Wollongong, one of us tried to determine whether ELKIN1 worked the same way in humans. They reprogrammed human stem cells to produce specialised nerve cells that respond to “touch” stimuli. In these human cells, ELKIN1 had similar functional properties of detecting touch.