Posted by Bob on January 26, 2011, at 1:26:41
In reply to A better DBS?, posted by SLS on January 25, 2011, at 23:59:58
> Another idea comes to fruition.
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> http://www.nerve.com/news/current-events/woman-cured-of-clinical-depression-by-revolutionary-surgery
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> It took them long enough. DBS works, in part, by flooding a pathologically overactive circuit with exogenous electric currents that disrupt their function by reducing the propogation of action potentials (nerve firings). One region of the brain that has demonstrated overactivity in depression is the subgenual cingulate Brodman's Area 25. To brag just a little, I would like to say that I came up with this same idea a few years ago when it seemed like common sense to investigate stereotactic tissue ablation in the overactive areas of the brain responsible for depression. It was the breakthrough work of Helen S. Mayberg, M.D and others who first identified these overactive brain regions. I just figured that a precise application of tissue ablation in these areas would serve to provide the same therapeutic benefits as DBS.
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> - Scott
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The problem with the DBS trials is that it seems from the research that somewhere between 40 and 60 percent of people respond to varying degrees and then there's the 40 to 60 percent that don't. Nobody knows why of course.There is also some controversy as to what the electrodes are actually doing, as the research indicates that it almost certainly is not mimicking the ablation caused by a surgical lesion. There are indications that the electrical stimulation is making certain tracts/pathways in the brain hyperactive. There also may be a dual near and far-field simultaneous effect involving inhibition at close proximity to the electrode and an excitatory effect at greater distances.
Then there's the question of the optimal target - anterior cingulate, nucleus accumbens, caudate nucleus, ventral anterior capsule, lateral habenula, etc. The anterior cingulotomy looks to in the dorsal region of the anterior cingulate and reverts back to ablation techniques, but with more advanced and accurate methods. This is an extremely interesting case as the trial at University of Bristol involved 4 electrodes stimulating two different areas... and only after that the woman received and additional anterior cingulotomy. Amazing. I wonder sometimes if the more accurate ablation techniques may be better in the future than the DBS stimulation.
Bob
poster:Bob
thread:977989
URL: http://www.dr-bob.org/babble/20110115/msgs/977993.html