The Memory Hacker

MELDING MIND AND MACHINE

Scientists´ increasing ability to map the basic structure of the brain has already produced a handful of machine implants that can compensate for damaged sensory systems. The artificial cochlea, for instance, has given hearing to the deaf, and artificial retinas are now in patient trials.

But the most dramatic achievement in humans so far is a neurosensor under development by brain researcher John Donoghue and his colleagues at Brown University. When placed over the brain´s motor-cortex area, the sensor enables quadriplegics to open and close a prosthetic hand merely by thinking about doing it. This technology, called BrainGate, allows the machine to convert the electronic signals coming from the brain (â€I want to move this handâ€) into motor activity by using algorithms embedded in a software chip. â€The possibilities are limitless,†says Elizabeth Razee of Cyberkinetics Neurotechnology Systems, a firm in Foxborough, Massachusetts, that hopes to bring BrainGate to market by 2009.

Cyberkinetics´s work bears some similarity to Berger´s. Both convert brain signals into code that can be interpreted and translated by a computer. But Berger has set himself the more difficult challenge. BrainGate offers a one-way link between mind and machine: The user can talk to a computer but not vice versa. Berger´s brain chip operates in two directions, functioning as a bridge over damaged cells.

The challenge of mathematically mimicking brain function-and the internal language it uses to communicate concepts like emotion and memory-is complicated by the fact that brain cells converse in a sort of secret electrical code. One cell â€talks†to another through pulses of electricity, the message of which depends on the time and frequency of their firing. These spatiotemporal patterns allow us to, for instance, gauge the distance between objects in a room and navigate around them.