May 14, 2013

Human Memory Implants May Soon Be Tested

Brain Implant

 Neuroscience
Neuroscientist Theodore Berger believes he has deciphered the code that the brain forms long-term memories, and he is almost ready to test silicon implants that could augment the brains memory functions.


Aworkgroup of neuroscientists from the University of Southern California (USC), Wake Forest University (WFU), the University of Kentucky and DARPA have developed a memory implant technique that could help restore memories lost by stroke and localized brain injury.

Electrode array feeds neural activity in the hippocampus to the chip which delivers output to the rest of the brain, bypassing damaged tissue.

The first step in restoring memories is to record, in undamaged tissue, the unique activity patterns associated with the formation of particular memories.  Step two is to use these patterns to predict what the “downstream” damaged areas should be doing.  Step three is to replicate the desired activity in healthy areas by stimulating brain cells with electrodes.

The research is focused on the hippocampus, where short-term memories are solidified into long-term ones by the movement of electrical signals through neurons.  Professor of biomedical engineering Theodore Berger of USC has used mathematical models to program electrodes to mimic these movements.

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Berger, who will be speaking at the Global Futures Congress later this year,  has designed silicon chips to mimic the signal processing that those neurons do when they are functioning properly—the work that allows us to recall experiences and knowledge for more than a minute. Ultimately, he wants to restore the ability to create long-term memories by implanting chips like these in the brain.

“I never thought I’d see this in my lifetime,” Berger told CNN. “I might not benefit from it myself but my kids will.”

Associate Professor Rob Hampson of Wake Forest University is also amazed by the success of their research: “We keep pushing forward, every time I put an estimate on it, it gets shorter and shorter.”

Hampson has concluded via rat and monkey studies that certain brain functions can be altogether replaced by electrode signals. Perhaps even the hippocampus itself may be bypassed one day: ”We support and reinforce the signal in the hippocampus but we are moving forward with the idea that if you can study enough of the inputs and outputs to replace the function of the hippocampus, you can bypass the hippocampus.”

Theodore W. Berger

The next step is to shrink down the electronic equipment into a much smaller device. Researchers hope for trials to start within the next two years with a small group of volunteers. They predict public availability in five to ten years.

If a memory implants sound like science fiction, Berger points to other recent successes in neuroprosthetics. Cochlear implants now help more than 200,000 deaf people hear by converting sound into electrical signals and sending them to the auditory nerve. Early experiments have also shown that implanted electrodes can allow paralyzed people to move robotic arms with their thoughts. Other researchers have had preliminary success with artificial retinas in blind people.
We are still a long way from understanding how even single neuron operates in the brain As exciting as these early memory implants may be, much research and neuron-level brain mapping still needs to be done to obtain an operational manual of our brain and it's wiring diagrams.

Even with these unknown factors, Berger and his colleagues are planning human studies. He is collaborating with clinicians at his university who are testing the use of electrodes implanted on each side of the hippocampus to detect and prevent seizures in patients with severe epilepsy. When and if the project moves forward as envisioned, Berger’s group will piggyback on the trial to look for memory codes in those patients’ brains.



SOURCE  MIT Technology Review

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