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Tuesday, June 14, 2011

The Brain. The Machine. The brain-machine interface?

http://teddysratlab.blogspot.com [Full link to blog for email clients.][FT:C44]

This is my final blog prior to an extended professional trip that takes me to California and the United Kingdom.  I am currently in Pasadena, CA on the initial part of the trip will involve a meeting where we discuss brain-machine interfaces.  In a few days I will leave for Scotland to write the third research grant application to be written and submitted between mid-may and July 5th.  A serialized short story will appear here starting Saturday to give me the time off to write even *more*!  Bwahahahahaha!

Brain Machine Interfaces.

No, we're not talking about either "Steve Austin, the Six-Million-Dollar Man" or Star Trek's Borg just yet.  Nor are we at quite the level of creating direct brain to computer links (let alone "mind" to computer).  But what *is* possible in neurally-based prosthetics is ... frankly ... mind-boggling.

The oldest actual *neural* interface is the artificial cochlea, shown here at left.   This device places an electrode into the cochlea to stimulate the auditory nerve at the same sites that a natural deflection of the basilar membrane would stimulate the hair cell neurons (see http://teddysratlab.blogspot.com/2011/03/and-ears-to-hear.html).  This is still not a "natural" or complete prosthetic because it relies heavily on a sound processor to pick the relevant frequencies out and send to the electrode.  The sound processor can be tuned for specific types of sound - most typically speech.

Neuroscientists are making great strides on other sensory prosthetics.  The company 2nd Sight, with it's Argus II retinal prosthetic (http://medgadget.com/2008/04/argus_ii_retinal_prosthesis_implanted_into_first_two_patients_in_europe.html) has several patients with the device that works by stimulating retinal neurons that remain after the photoreceptor cells deteriorate from disease.  Again, not a complete prosthetic, and neither of these are direct brain-to-machine interfaces, but the progress is astounding I have seen the patients and heard their stories.  Amazing.[Update:  They have patients *READING*!]

These are "sensory prosthetics" which restore the input functions to the brain.  We don't have taste and smell prosthetics, but work on tactile prosthetics is improving, and we'll get to that later in relation to prosthetic limbs. 

Another prosthetic from the same group is the "Bion" which is an implant that can restore muscle function following paralysis (http://medgadget.com/2008/10/bion_implantable_nerve_stimulator_for_chronic_headache_1.html).  It has found use in migraine relief, correcting incontinence and in reducing muscle spasm and rigor caused by disease (i.e. Parkinson's Disease) or spinal injury.

Full limb prosthetics have been around for many years, but with very little complexity, and only restoration of simple motions.  Arm prosthetics have long been only cosmetic or simple claws.  Leg prosthetics have become much more sophisticated as engineers have studies "kinematics" (motion) to develop spring and joint-loaded models (left) that provide a lot of function *without* neural connections.

The real winner in the field is the "DARPA Prosthetic Arm" funded by the "Revolutionizing Prosthetics" effort of the Defense Advanced research Projects Agency (DARPA), which frankly, funds concepts that most folks would think of as Science Fiction.


The DARPA Arm (actually two, there have been two main phases to the project,  http://www.neurotechreports.com/pages/darpaprosthetics.html) incorporates a neuron to device linkage to control reach, flex, grasp and maneuver the arm.  Two means are considered to interface it (A) using the remaining nerves that *would* have served the missing limb, or (B) direct to the motor cortical areas of the brain.

A major hurdle in development of a complete prosthetic is feedback of tactile sensory information to the brain.  At present it is still a barrier, but two approaches - interface direct to the somatosensory cortex, or interface to the thalamus - are under consideration.

Still none of these are the brain-to-machine control interfaces of The Matrix.  We just are not there yet.  Current devices are mostly just on-off switches, either using EEG (http://www.economist.com/node/8847846?story_id=8847846) or implanted electrodes (http://www.braingate.com/) granted, the Brain Gate is a *lot* of on-off switches!  To be fair, much of the original work with limb prosthetics requires the recording of neural activity to be processed or modeled by computer, so there is much work being done in animals with brain-to-computer interfacing, just not much with humans at present.

So we have brain input prosthetics, like the cochlea and retina, and output prosthetics such as the limb and Brain Gate.  Are there prosthetics that operate completely inside the brain the bypass areas damaged by disease or trauma?  Well, yes, there is work on that front as well.   Dr. Theodore Berger heads a team that is working on a prosthetic for the hippocampus (http://www.neural-prosthesis.com/).  The principles involved in the work are actually applicable to many different brain areas, and could be used to reconnect different parts of the brain and bypass injuries following stroke, trauma, tumor, or surgery.

The possibilities are staggering.  We are not there yet, but if you just know where to look, the roots of the "bionic" or "cyborg" age are upon.  While I would not want to be "assimilated," I sure do like the idea that some day in the near future we will have the means to replace - perhaps not perfectly - functions that are lost to accident or disease.

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Thanks for keeping up with The Guide.  It's been a grueling few months, and I apologize for lapses in the schedule.  I hope you enjoy the entertainment lined up for the next two weeks.

I'll "catch you on the flip side!"

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