Mark Dombeck, Ph.D. was Director of Mental Help Net from 1999 to 2011. Dr. Dombeck received his Ph.D. in Clinical Psychology in 1995 ...Read More
The latest issue of MIT’s Technology Review magazine has an article on "Young Innovators" for 2006. A number of young researchers who have produced interesting and promissing technologies are profiled therein. One of the profiles caught my eye, the one for Edward Boyden, age 27, who recently invented a method for artificially firing neurons. Dr. Boyden’s invention may someday have important medical and psychiatric implications, and so it is worth mentioning here.
As you may or may not know, the brain is composed of numerous neurons (brain cells) which are organized into networks. One neuron butts up to another, forming long chains of neurons through which electrical impulses are sent. There are billions of such neuron chains in the brain. Working together in parallel, these chains or networks enable people (and some animals too) to have mental and emotional lives, and to keep our body parts syncronized and healthy.
There are a variety of disabing diseases, such as Parkinson’s and Schizophrenia, that affect the brain and result in the loss or malfunction of neurons and brain networks. In Parkinson’s, for instance, an important group of brain cells starts to die off. The cells that die produce a key neurotransmitter chemical known as Dopamine which is vital for making the surviving neurons work properly. Under normal conditions, neurons do not fire (send an electrical signal down their length) until they are chemically stimulated. In Parkinson’s disease, there is less Dopamine present, and therefore the rest of the neuron networks in the brain have trouble working properly. Doctors treat Parkinson’s patients with a drug that mimics the action of Dopamine, but the efficiency of this treatment is less than optimal and only works so well, in part becuase it is difficult to get the drug in the right amounts to the right places in the brain.
Dr. Boyden has invented a method for making neurons fire when you shine a light on them. He has done this by taking a naturally occuring gene from a type of algae and inserting that gene into neurons inside a rats brain. I don’t know how he managed to pull this off – it sounds fantastic, but that is what he has managed to do. The thing about this gene, known as ChR2, is that it gets excited when you shine a light on it. Once the gene is inside the rat neurons, those rat neurons, become reactive to light. If you shine a green light on the neurons, they glow. If you shine a blue light on them, they excite and fire.
So, potentially (and this is a BIG potentially), someday it may be possible to control aspects of a person’s brain with light. How would the light get in there, you might ask? Easy. A brain surgeon would implant a set of miniature fiber optic cables ajacent to key neurons in a person’s brain, and each fiber so implanted could control the firing of a different neuron chain. In a scenario like this one, you might not need drugs to help a Parkinson’s patient – you’d just need genetic and surgical treatments and then a small computer to control the light impulses, and you might be in reasonable shape. Such brain-pacemakers might offer relief for a variety of conditions.
This ain’t happening any time soon, I don’t think. There are the ethics of implanting foreign genes into humans for one thing. the cost of such treatment, and the costs of neurosurgery necessary to implant the fiber optics. Etcetera. It is also maybe overkill. Simpler technology such as implantation of regular old electrodes (which can get neurons excited by zapping them with a little current) might do the trick. Consider advances using this sort of present day technology with regard to Vagus Nerve stimulation for depression. Still, heart pacemakers and vagus nerve stimulators were once science fiction too. What is described is a sort of brain pacemaker, so why not? It is at least possible.
More likely, the real application of Dr. Boyden’s invention is to better map out brain circuitry in living brains. The more researchers can figure out exactly what brain circuits are involved in particular conditions like Schizophrenia, Obsessive-Compulsive Disorder, Depression, etc., the better they can advance treatment for these conditions.