Researchers at University of Southern California are preparing to implant a silicon silicon chip in a rat's brain. This chip is the world's first brain prosthesis, designed to replace the hippocampus, a part of the brain that is involved in storing long term memories.
Theodore Berger and his colleagues have been working on the project for 10 years. They will test the chip on tissue from rats brains before they test it on live rats and laboratory monkeys. If the initial research goes well the brain prosthesis could be used for people who face memory loss due to Alzheimer's disease or other disorders.
According to an article in New Scientist the prosthesis "mimics the way the hippocampus encodes experiences before sending them to be stored elsewhere in the brain as long-term memories" (Graham-Rowe 2003)
In order to design the chip the team sliced sections of rat hippocampus and stimulated these slices repeatedly with electrical signals. Eventually they determined which output resulted from a given electrical input.
The team put together information from the slices to build a mathematical model of the entire hippocampus, looking at it as an array of neural circuits that work in parallel to process data. The model was transferred onto a chip that communicates with the brain through electrodes that are placed on either side of the damaged area. The electrodes detect the electrical activity coming in from the rest of the brain and send electrical instructions back out to the brain.
After testing the chip on live rats the team plans to test it on monkeys who are trained to carry out memory tasks. They plan to actually stop part of the monkey's hippocampus from working and bypass it with the programmed chip.
The research raises several ethical issues. If such a device is one day used on humans it will be used on humans with Alzheimer's Disease; or with others who have problems laying down long-term memories. Can such a person give consent to the surgery if they can't lay down long-term memories? Is a person the same person after one or more brain regions have been replaced by computer chips?
<P class=wallacepara>Reference:Graham-Rowe, Duncan. World's first brain prosthesis revealed. New Scientist, March 2003. <!-- interp: /Widgets/toolboxnew/0,4690,4623964,00.html -->