A study published recently in the scientific journal Nature Neuroscience revealed that scientists have created genetically modified mice whose neurons respond to light stimulation. A MedIndia article reported that researchers at the Department of Neuroscience at the Karolinska Institutet in Sweden had engineered a mouse in which, ‘Shining blue light on brainstems or spinal cords isolated from these mice produces walking-like motor activity.’ The discovery holds great implications for possible future spinal cord injury treatments.
The research team used a light sensitive protein extracted from algae to engineer neural cells in mice in order to elicit motor activity in the cells. The protein, Channelrhodopsin2 (ChR2) activates the cells in which it is found when hit by blue light. The purpose behind inserting the ChR2 protein into neural cells is to allow scientists to ‘selectively activate excitatory neurons in specific regions of the brain stem and spinal cord, as the excitatory neurons are believed to be important for initiating locomotion, or walking,’ the article read.
The researchers were successful at eliciting the motor response they hypothesized. ‘When blue light was shined directly on the spinal cord, walking-like activity began and was maintained for the duration of the light pulse.’ In human models, the discovery could prove useful in retraining the brains and nervous systems of spinal cord injury victims to be able to walk after suffering paralysis.
Wired magazine reported on similar research conducted in 2007 at Stanford University. The Stanford researchers discovered that ‘a beam of light could control brain activity with great precision,’ the article noted.Â The Stanford study was conducted using injections of viral particles, which proved dangerous, at least in mice models, while the group at Karolinska used genetic modification to elicit the expression of ChR2 in the mouse’s neurons.
More research must occur to understand and develop the possible light-based treatment before it can be tested in humans. The research can be seen as another extremely significant step in the direction of one day curing paralysis and assisting spinal cord injury patients on their way back to full recoveries.
Chorost, Michael. (October 19,2009) ‘Algae and Light Help Injured Mice Walk Again.’ Retrieved on February 2, 2010 from the Wired Web site:http://www.wired.com/magazine/2009/10/mf_optigenetics/
Karolinska Institutet. (January 25, 2010) ‘New Blue Lit Neurons Improve Walking After Spinal Cord Injury: Scientists.’ Retrieved on February 2, 2010 from the MedIndia Web site:http://www.medindia.net/news/New-Blue-Lit-Neurons-Improve-Walking-After-…