We like to think that all our smarts are contained in our brain, but researchers at Umea University in Sweden have found that the neurons that extend into our fingertips perform the same sorts of calculations that take place in the cerebral cortex.
In other words, what we've been told about our entire nervous system acting as a sort of network of data-collecting sensors that send that data back to the brain to be processed might not be quite right.
In the abstract for a study published online August 31 by the journal Nature Neuroscience, J Andrew Pruszynski & Roland S Johansson write: "We submit that peripheral neurons in the touch-processing pathway, as with peripheral neurons in the visual-processing pathway, perform feature extraction computations that are typically attributed to neurons in the cerebral cortex."
Translation, please.
"Somewhat simplified, it means that our touch experiences are already processed by neurons in the skin before they reach the brain for further processing," says Pruszynski in a release.
The study also describes the ability of skin neurons to relay what Pruszynski calls "geometric data" of touched objects.
"Our work has shown that two types of first-order tactile neurons that supply the sensitive skin at our fingertips not only signal information about when and how intensely an object is touched, but also information about the touched object's shape."
The sensitivity of this system depends on the layout of a neuron's highly-sensitive zones in the skin.
The discovery has the potential to change current approaches to rehabilitation following a nerve injury, since the current assumption is that the cerebral cortex is doing all the work in that system.
“If you are working toward regrowing peripheral nerves to recover touch function in people with nerve injury, it is important to consider not just how many neurons grow back, as is often the case, but now based on our findings precisely how these neurons grow back as this may be critical to the type of information they send the brain,” Pruszynski said.
