Summary: Newly identified nerve pathway, which runs down the same side of the body, may bypass a damaged spinal cord. The findings could shed light on some neurological disorders such as referred itch or jogger’s migraine.
Source: Curtain University
The research, published in Frontiers in Neuroscience, discovered a nerve pathway that runs down the same side of the body, potentially bypassing a damaged spinal cord, which could explain neurological conditions such as referred itch and some types of migraine.
Lead author Adjunct Associate Professor Dr Morry Silberstein, from the School of Molecular and Life Sciences at Curtin University, said the spinal cord played a crucial role in the functioning of the human body, including the movement of our limbs.
“An intact spinal cord is critical, as messages or transmissions are sent to the limbs through the spinal cord from the brain. Previous researchers have explored ipsilateral sensory transmission, where people experience referred pain or sensation on the same side of the body, by placing a healthy person’s foot in painfully cold water that caused increased blood flow to the same side of the face,” Dr Silberstein said.
“We wanted to test if this was also the case for spinal cord injury patients and by applying the same technique, we were able to show similar blushing in the face. We then managed to stop this response by temporarily knocking out small fibre nerves in thigh skin on the same side of the body by using a topical cream called capsaicin, potentially bypassing the spinal cord.”
Dr Silberstein explained that further research was needed to determine whether this newly discovered nerve pathway may be applied in helping spinal cord patients to learn to walk again.
“Our initial findings offer very promising outlooks for this type of injury and perhaps one day it may be possible to train spinal cord-injured patients to recognise facial flushing as an indicator of foot impact on the ground,” Dr Silberstein said.
“There is still a lot to learn about this newly discovered pathway and it is recommended that larger groups of patients with spinal cord injuries are tested to see if similar results are found.”
The research was co-authored by researchers from Austin Health Melbourne, Murdoch University, RMIT University, and the University of Melbourne.
Lucien Wilkinson – Curtain University
The image is in the public domain.
Original Research: Open access
“A Human Sensory Pathway Connecting the Foot to Ipsilateral Face That Partially Bypasses the Spinal Cord”. Morry Silberstein, Andrew K. Nunn, Peter D. Drummond, Dawn Wong Lit Wan, Janette Alexander, Melinda Millard and Mary P. Galea.
Frontiers in Neuroscience. doi:10.3389/fnins.2019.00519
A Human Sensory Pathway Connecting the Foot to Ipsilateral Face That Partially Bypasses the Spinal Cord
Human sensory transmission from limbs to brain crosses and ascends through the spinal cord. Yet, descriptions exist of ipsilateral sensory transmission as well as transmission after spinal cord transection. To elucidate a novel ipsilateral cutaneous pathway, we measured facial perfusion following painfully-cold water foot immersion in 10 complete spinal cord-injured patients, 10 healthy humans before and after lower thigh capsaicin C-fiber cutaneous conduction blockade, and 10 warm-immersed healthy participants. As in healthy volunteers, ipsilateral facial perfusion in spinal cord injured patients increased significantly. Capsaicin resulted in contralateral increase in perfusion, but only following cold immersion and not in 2 spinal cord-injured patients who underwent capsaicin administration. Supported by skin biopsy results from a healthy participant, we speculate that the pathway involves peripheral C-fiber cross-talk, partially bypassing the cord. This might also explain referred itch and jogger’s migraine and it is possible that it may be amenable to training spinal-injured patients to recognize lower limb sensory stimuli.