Blog #29: Brain-Implanted Laser Light Stops Seizures

(This blog was originally posted on December 2, 2012)

 

 

 

 

Recent animal research has shown that a laser beam emitted from a tiny cannula that was inserted into epileptic rats’ brains can stop focal seizures (seizures that originate in one part of the brain).

This exciting research was reviewed in a recent issue of Neurology Today (1). An investigative team led by Laura Mantoan Ritter, MD, of the Institute of Neurology at University College London, was able to manipulate chemical changes in rats’ brains and stop seizures. Normal brain neuron cells function by electrochemical changes that induce “firing.” The researchers activated specific genes that control neuronal firing. Abnormal firing directly relates to epileptic seizures. There are genes within cells that operate channels which traverse cell membranes. These channels convey particular chemicals in and out of the neuron and the chemical changes that occur influence cells and how they function and fire. There are specific genes that have light-sensitive properties. Such genes were taken from microorganisms (viruses, bacteria and similar living cells). The scientists embedded these particular genes into viruses and the viruses were then implanted within cells in the brains of living epileptic rats. These genes began to operate within the rats’ brain neurons from which seizure discharges emanate.

It has been observed that certain genes have sensitivity to particular light-beam wave lengths. This phenomenon is called optogenetics. The scientists implanted optic fibers at the site of abnormal neurons from which focal seizures originated in these rats. Controlled wave-length laser beams were emitted at these neurons. Green light emissions had a positive electrochemical effect on the cells containing these optic-sensitive genes. Seizures were suppressed.

This promising research brings hope that seizures which affect one brain area (e.g., complex partial seizures), rather than the entire brain (e.g. convulsions), can be stopped before they even begin by activating the laser beam into the abnormal brain area. However, the researchers emphasize that it is too early to say that optogenetics will be applicable to human epilepsy. 

(1) Robinson R. Turn on a Light, Turn off a Seizure? Optogenetics Comes to Epilepsy. Neurology Today. November 15, 2012; Volume 12(22); pp 1, 6–9.

 

Lance Fogan, M.D. is Clinical Professor of Neurology at the David Geffen School of Medicine at UCLA. DINGS is his first novel.