When you reach into your pocket, you can easily tell a button from a coin. But how? Solving this seemingly simple problem is actually amazingly complicated.
The long-held scientific explanation is that neurons in the cerebral cortex, which is the part of the brain reserved for the most complicated functions, make the differentiation. But recent findings from a new recruit to Western University show it may actually be touch neurons in the skin correctly identifying your pocket change.
In a paper entitled Edge-orientation processing in first-order tactile neurons, Andrew Pruszynski and his collaborator and current supervisor Roland S. Johansson from Umeå University in Sweden shared their discovery, which redefines how touch signals are processed by the nervous system and may have a big impact on rehabilitation treatments and exercises following nerve injury, as current strategies are based on the assumption that the cerebral cortex does all the work. The paper was published last month in Nature Neuroscience.
Pruszynski joins Western’s Schulich School of Medicine & Dentistry and the Faculty of Social Science this winter as an assistant professor in the Department of Physiology and Pharmacology and the Department of Psychology, respectively. Currently a postdoctoral fellow at Umeå’s Department of Integrative Medical Biology, Pruszynski will also be a principal investigator at Western’s Brain & Mind Institute.
“Our findings show computations previously attributed to processing in the most sophisticated parts of the brain, like the somatosensory cortex, are already happening in the first neurons of the nervous system, literally those that end in the skin,” Pruszynski said.
The findings redefine the role of peripheral tactile neurons from passive wires that merely transmit touch information to the brain for further processing into active components of the extraction process making them critical to sensory perception and motor control.
“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.
The research team used a technique called microneurography, which allowed them to record data from single neurons in the peripheral nervous system of awake and cooperative human participants.
“There is no doubt that Western University, the Department of Physiology and Pharmacology, the Department of Psychology and the Brain and Mind Institute, offer a truly world-class environment for studying cognitive neuroscience,” Pruszynski said. “It’s hard for any other place in the world to match the wealth of fantastic people, equipment and physical space available in London.”