brainchips....need a little onion dip?

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NewScientist.com

 

 

World's first brain prosthesis revealed

 

 

The world's first brain prosthesis - an artificial hippocampus - is

about to be tested in California. Unlike devices like cochlear

implants, which merely stimulate brain activity, this silicon chip

implant will perform the same processes as the damaged part of the

brain it is replacing.

The prosthesis will first be tested on tissue from rats' brains, and

then on live animals. If all goes well, it will then be tested as a

way to help people who have suffered brain damage due to stroke,

epilepsy or Alzheimer's disease.

Any device that mimics the brain clearly raises ethical issues. The

brain not only affects memory, but your mood, awareness and

consciousness - parts of your fundamental identity, says ethicist Joel

Anderson at Washington University in St Louis, Missouri.

The researchers developing the brain prosthesis see it as a test case.

" If you can't do it with the hippocampus you can't do it with

anything, " says team leader Theodore Berger of the University of

Southern California in Los Angeles. The hippocampus is the most

ordered and structured part of the brain, and one of the most studied.

Importantly, it is also relatively easy to test its function.

The job of the hippocampus appears to be to " encode " experiences so

they can be stored as long-term memories elsewhere in the brain. " If

you lose your hippocampus you only lose the ability to store new

memories, " says Berger. That offers a relatively simple and safe way

to test the device: if someone with the prosthesis regains the ability

to store new memories, then it's safe to assume it works.

Model, build, interface

The inventors of the prosthesis had to overcome three major hurdles.

They had to devise a mathematical model of how the hippocampus

performs under all possible conditions, build that model into a

silicon chip, and then interface the chip with the brain.

No one understands how the hippocampus encodes information. So the

team simply copied its behavior. Slices of rat hippocampus were

stimulated with electrical signals, millions of times over, until they

could be sure which electrical input produces a corresponding output.

Putting the information from various slices together gave the team a

mathematical model of the entire hippocampus.

They then programmed the model onto a chip, which in a human patient

would sit on the skull rather than inside the brain. It communicates

with the brain through two arrays of electrodes, placed on either side

of the damaged area. One records the electrical activity coming in

from the rest of the brain, while the other sends appropriate

electrical instructions back out to the brain.

Memory tasks

Berger and his team have taken nearly 10 years to develop the chip.

They are about to test it on slices of rat brain kept alive in

cerebrospinal fluid, they will tell a neural engineering conference in

Capri, Italy, next week.

" It's a very important step because it's the first time we have put

all the pieces together, " he says. The work was funded by the US

National Science Foundation, Office of Naval Research and Defense

Advanced Research Projects Agency.

If it works, the team will test the prosthesis in live rats within six

months, and then in monkeys trained to carry out memory tasks. The

researchers will stop part of the monkey's hippocampus working and

bypass it with the chip. " The real proof will be if the animal's

behavior changes or is maintained, " says Sam Deadwyler of Wake Forest

University in Winston-Salem, North Carolina, who will conduct the

animal trials.

The hippocampus has a similar structure in most mammals, says

Deadwyler, so little will have to be changed to adapt the technology

for people. But before human trials begin, the team will have to prove

unequivocally that the prosthesis is safe.

 

Collateral damage

One drawback is that it will inevitably bypass some healthy brain

tissue. But this should not affect the patient's memories, says

Berger. " It would be no different from removing brain tumors, " where

there is always some collateral damage, says Bernard Williams, a

philosopher at Britain's University of Oxford, who is an expert in

personal identity.

Anderson points out that it will take time for people to accept the

technology. " Initially people thought heart transplants were an

abomination because they assumed that having the heart you were born

with was an important part of who you are. "

While trials on monkeys will tell us a lot about the prosthesis's

performance, there are some questions that will not be answered. For

example, it is unclear whether we have any control over what we

remember. If we do, would brain implants of the future force some

people to remember things they would rather forget?

The ethical consequences of that would be serious. " Forgetting is the

most beneficial process we possess, " Williams says. It enables us to

deal with painful situations without actually reliving them.

Another ethical conundrum concerns consent to being given the

prosthesis, says Anderson. The people most in need of it will be those

with a damaged hippocampus and a reduced ability to form new memories.

" If someone can't form new memories, then to what extent can they give

consent to have this implant? "

 

It took ten years to develope and how many humans involved in non

consentual experiments did the Navy use to get the data.

 

 

..b b.b.