Scientific American has a neat piece of news in its February 2007 issue (“Chipping In” by Anna Griffin; subscription required for full text). For some time, we have had technology that can pick up signals from neurons (brain and nerve cells), for instance, allowing paralyzed patients rudimentary control over a computer or prosthesis.
But a team at the University of Southern California, led by Theodore W. Berger, have taken this a step further. For twenty years he and his team studied the brains of rats; specifically, how neurons communicate in the hippocampus, a region of the brain involved in memory. They developed a model of how the neurons responded to various inputs and built it into a chip. They then took slices of hippocampal tissue, removed part of it, and replaced it with the chip, “[restoring] function by processing incoming neural signals into appropriate output with 90 percent accuracy,” according to the Scientific American article.
I find this to be very exciting. This sort of research could one day lead to devices to help humans with brain damage or memory problems, for instance, though of course that is still far away. Even at this stage, it took some interesting engineering work to figure out how to make a silicon chip interact with brain tissue. The next step will be to design a chip to work with a living brain, instead of tissue slices.
But what really fascinates me is that they were able to model the function of that brain tissue mathematically, to calculate how the section of neurons would respond to various inputs. This brings us closer to understanding just how brain functions such as memory and consciousness arise from the biology and chemistry of the brain.
It does suggest some future ethical and philosophical puzzles, though. Will we eventually be able to reproduce the functioning of the entire rat brain? How about that of a human? Might we one day be able to calculate the functioning of a human mind, to reproduce a mind as software?
My brain looks forward to future advances.