[BobbyB]

Bionic Research Background

Miguel Nicolelis, and Jose Carmena
with robot arm (Credit: Duke University)

For decades, scientists have been interested in developing a technique for interpreting brain activity to motor output — in other words, decipher the brain's electric patterns and convert them into coherent thought.

The first attempts at a brain-computer interface were performed in the late 1960s and early 1970s. Human subjects were able to control the generation of certain brain waves, called alpha waves, that were picked up by an electroencephalogram (EEG), a noninvasive apparatus used to measure the brain's electrical activity, giving insight to certain states of mind, voluntary intentions, and visual stimuli. Similar experiments were later successfully conducted with beta, mu, and theta rhythms. However, to achieve greater accuracy in reading brain patterns, a more invasive method was needed to be able to read signals, or neurons, from individual brain cells. In the early 1970s, the pioneering experiments of Eberhard Fetz and his colleagues from the University of Washington demonstrated that monkeys could be trained to control neural patterns picked up by an electrode inserted adjacent to the neuron being monitored. A few years later, Edward Schmidt from the United States’s National Institutes of Health raised the possibility that voluntary motor commands could be extracted from neural patterns and implemented to help severely paralyzed patients operate a prosthetic device.

It took nearly two decades after Schmidt's proposition until the technical bottlenecks that had to be passed were overcome and technologies were developed that enabled the recording of neural patterns from multiple sites. These technologies allowed the demonstration that neuronal activity patterns could be recognized using pattern-recognizing algorithms and, later, the first demonstration that neuronal population recordings in rats and rhesus monkeys could actuate a robotic device with a single degree of freedom. In a 1999 groundbreaking experiment from the laboratory of Miguel Nicolelis from Duke University, primate arm reaching was reproduced by reading brain patterns.

The past decade has provided an overwhelming amount of knowledge and scientific breakthroughs at a stunning pace, giving hope that brain-machine interfaces (BMIs) will be put into clinical use in the very near future.

http://www.tfot.info/articles/1004/m...nic-limbs.html