People who have lost the use of their legs following a spinal cord injury may hope to be able to walk once more one day thanks to the identification of a new neurological target during a study conducted by researchers at Laval University.

This hope is basically possible, since spinal cord injuries are rarely complete. The brain therefore retains access to the spinal cord circuit located under the injury. However, this link is often dormant.

Deep brain or electrical stimulation might potentially awaken this link and thus stimulate recovery of the ability to walk.

The team led by Frédéric Bretzner, a professor at the Faculty of Medicine at Université Laval, focused on a very specific part of the brain, namely the mesencephalic locomotor region.

This part of the brain has long been recognized as being able to initiate and accelerate walking in several animal species. It is composed of two nuclei, the wedge-shaped nucleus and the pedunculopontine nucleus.

“The region we targeted is organized by these two nuclei which contain excitatory neurons and inhibitory neurons. Studies have already shown that we can improve walking by stimulating some of these nuclei, but we wondered if one might be more effective, ”explains the professor.

The research team has obtained interesting results on animals, using optogenetics, which notably allows the stimulation of neurons by light.

“Our results suggest that the cuneiform nucleus would be a better neurological target than the pedunculopontine nucleus for improving gait recovery in people with spinal cord injury,” Prof. Bretzner reports.

He points out that the pediculopontine nucleus, which is currently a therapeutic target for patients suffering from Parkinson’s, does not demonstrate gait stimulation. On the contrary, he stops it.

For now, there are no optogenetic tools suitable for humans. However, while waiting for this possibility, the researcher indicates that electrical stimulation of the cuneiform nucleus might already improve gait recovery in patients with spinal cord injury and people suffering from neurodegenerative diseases, such as stroke, amyotrophic lateral sclerosis or Parkinson’s disease.

The research work of Professor Bretzner’s team is continuing, in particular to assess whether other neuronal populations might be even more effective.