Sensory neurons located in your fingertips perform mathematical calculations that provide geometric information about objects you touch, a new study has found.
Stereognosis is the ability to perceive and recognise the form of an object in the absence of visual and auditory information, by using tactile information to provide cues from texture, size, spatial properties, and temperature.
It was long believed that such computations were only reserved for neurons in the brain, but researchers observed that first-order tactile neurons packed into the skin of our fingertips are able to signal information about the edge orientation of a touched object to the brain. These peripheral neurons, which are engaged when a fingertip examines an object, perform the same type of calculations done by neurons in the cerebral cortex.
Touch, or tactile, perception is part of the somatosensory system. This complex system receives information from the environment via specialised receptors and relays the data to the central nervous system. The tactile system includes nerves called first-order neurons that extend into the skin and process touch. These neurons are heavily branched, meaning they receive information from many highly sensitive zones on the skin. Furthermore, according to the new research, this arrangement also allows individual neurons to identify geometric features of the objects that we touch.
“Somewhat simplified, it means that our touch experiences are already processed by neurons in the skin before they reach the brain for further processing,” said lead author Andrew Pruszynski.
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