Researchers at the medical university Karolinska Institutet, Stockholm Sweden, have created a genetically modified mouse in which certain neurons can be activated by blue light. Shining blue light on brainstems or spinal cords isolated from these mice produces walking-like motor activity. The findings, which are published in the scientific journal Nature Neuroscience, are of potential significance to the recovery of walking after spinal cord injury.

"We hope that our findings can provide insight that eventually will contribute to treatments for spinal cord injured patients," said Professor Ole Kiehn, who led the study, in a statement.

Excitatory neurons have been suggested to play an important role for the initiation and maintenance of locomotion, or walking. To test the hypothesis that activation of excitatory neurons is essential to locomotion, a research team at the Department of Neuroscience, Karolinska Institutet, created a genetically modified mouse that expresses a light sensitive protein in excitatory neurons.

Walking-like activity could also be initiated by exposing the lower brainstem to blue light, demonstrating that excitatory cells in the brainstem provide a sufficient ‘go’ signal to the spinal neurons involved in walking.

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[Source: Karolinska Institutet]