This week I watched a video by Ed Boyden, a neuroscientists at MIT and expert in optogenetics. Boyden's lab works on implanting optic transmitters and receivers in animal brains in order to control certain parts of behavior. The propose of this research is to discover the function of certain transmitters and how to treat disorders associated with them.
Boyden's lab starts the process by infecting an animal's brain with adeno-associated viruses (AAV) which targets certain cells and creates photoactived gated channels in the targeted cells. These channels act similar to sodium channels in that they produce an action potential but because they are photo activated, they can be stimulated by light being pumped into the brain. AAVs are useful because they act like most viruses, inserting their genetic material into the DNA of infected cell but they are not known to cause any diseases in humans, so it is safe to say this research is relent. Next, optic fibers are placed into the brain to induce the photo-stimulated cell whenever an external forces chooses (is the light on up there?). Now, a circuit has been created, on one end light that is controlled, on the other cells targeted by AAV to be stimulated.
Using these circuits Boyden's lab has reversed classical conditioning. The reversing of classical conditioning is of interest because it could be used to treat extreme phobias or more importantly to treat posttraumatic stress syndrome. The reversal is accomplished by taking whatever stimulus triggers the fear and pairing it with a flash of light in the brain triggering dopamine synapses target by the AAV, essentially rewarding the person for having experienced the stimulus. The use of this technique is really just high tech operant conditioning but is impressive because it works quickly and without electricity (which tends to favor only a few well working cells as opposed to all).
I decided to blog about this video because the class spent this week talking about ways to simplify the complexity of nervous systems. Being able to target one type of animal brain cell and stimulate it quickly and in a fairly controlled manner would enable researchers to create controls, consequently enabling the simplification of more complex brains (to some degree that is). I also found the video pretty cool and if you want to check it out the link is below.
Brighter Minds, Brighter Future
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As a stroke-addled survivor I can see multiple uses for this getting easy neuroplasticity to work better(penumbra or bleed drainage damage) or hard neuroplasticity(kicking out some functions in order to place functions from the dead area into them. Hopefuly you are smart enouogh to not allow your executive control to be taken over by motor functions. Or maybe you want to use this for negative neuroplasticity(reduce the number of neurons controlling something from 1000 to a few or even one), that allows to freed neurons to take on other functions. Explore that, I'm sure research experiments could be set up for proving it in humans, there would be lots of volunteers.
Snaps for the cool video!
I commented too soon, you may want to look at this article:
http://scienceblogs.com/neurophilosophy/2010/07/remote_control_of_animal_behaviour_using_magnetic_nanoparticles.php
It has this statement in it:
Nanomagnetic neuronal activation could prove to be very useful for investigating the functioning of cells within complex neural networks, and the authors suggest that it has several advantages over another recently developed technique called optogenetics, which involves using laser light to activate specified cells. Although extremely powerful, optogenetics is limited in its applications, because light has to be targeted precisely to groups of specified cells, and does not penetrate biological tissue very deeply. By contrast, magnetic fields can go straight through tissue virtually unhindered, and can be applied to whole organisms or even groups of them.
I personally like nanoparticles better because it can have so many uses; crosses the blood-brain barrier, attach therapeutic drugs to stop the cascade of neuronal death, they can be magnetically directed so tPA could be directed directly to the clot rather that the bleed inducing quantities today. So much to research and so few doing it.
Hey Dean,
I believe the advantage of optogenetics is derived from its limited strength. I always try to keep in mind if something is powerful enough to have big impact, often it has the strength to act in a manner difficult to predict. Meaning, the less variables existing in a situation is directly correlated to fewer things able to go wrong.
This is the really intriguing thing about optogenetics, it is able to selectively control exactly what is activated. Even if something goes wrong when implanting the viruses, an individual has the ability to simply not deal with those consequences by not turning on a light in the location.
I would be skeptical of placing magnesium in a brain for this reason alone. Prolonged use might demonstrate a lessened ability to control the mechanism responsible for the results (magnesium is a fairly reactive base after all) and avoiding magnetic fields can be difficult, especially if one has brain injuries (MRIs might pose a problem).
Thanks for you interest and hope you enjoyed the article/video =)
-frenz059