TECHNOLOGY FOR CHANGE

Optogenetics Offers Insight into the Last Frontier: The Brain

Dave Greenfield | Date: 02-23-10 | Comments

A new branch of science lets scientists turn parts of the brain on and off, enabling a host of new applications.

There is a new science-fiction book about scientists who can activate and deactivate different parts of the brain with lasers; they can turn behavior on and off like a switch. Oh wait, that�s the news. As technology advances, the far-fetched becomes a little less impossible. Optogenetics is a relatively new field of study that allows scientists to control brain neurons. While we may not be getting a remote control for our spouse or children anytime soon, there are a host of practical applications for this technology.

Optogenetics is in its infancy, but it offers a look into the brain that traditional methods cannot. Typically, brain function was studied by stimulating individual nerve cells and noting the responses. This is akin to performing delicate surgery with a big pair of work gloves on. Optogenetics takes the gloves off and allows greater precision. Genetic engineering is combined with light technology to observe groups of neurons and individual neural circuits, and what�s more, control them.

Neuroscientists at MIT have recently discovered how to use light to slow down activity in the brain. This temporary cessation in activity has the potential to provide immense relief for those conditions related to abnormal brain activity, such as chronic pain, epilepsy, Parkinson�s disease, and even depression and schizophrenia. MIT researchers, led by Dr. Ed Boyden, found two light-sensitive proteins, called the Mac and Arch genes, that can be engineered into the brain to facilitate the �digital shutdown of neurons,� as Dr. Boyden puts it.

�Light activates the proteins, which lowers the voltage in the neurons and safely and effectively prevents them from firing,� says Dr. Boyden. �In this way, light can bathe the entire brain and selectively affect only those neurons sensitized to specific colors of light.�

Currently, researchers are gaining far more access to and control of brain circuits in lab animals, including fruit flies, rats and monkeys. The transition to human brains depends on the ability to send the genes and light to neurons safely. But even if Mac and Arch never make it into a human brain, the data they are providing scientists is very likely to lead to medical discoveries for a wide range of conditions, from spinal cord injuries to mental illnesses. �We can use these tools for real principles of treatment,� he adds.