Berger engineered the chip using mathematical models based on rat brain circuits. He'll test it on slivers of brain tissue spliced from a rat's hippocampus--gray matter responsible for retaining new, long-term memories. In the experiment, millions of neurons embedded in the tissue will transmit their electrical impulses to attached electrodes. If all goes according to plan, the electrodes should intercept the signals and reroute them to the chip, which fills in for the damaged neural circuits to process the data and shoot it back to other neurons. "It's an elegant experiment," says computer neuroscientist Richard Granger at the University of California at Irvine. "And a tantalizing glimpse of things to come."