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The world's first brain prosthetic, or hippocampus replacement chip, was revealed in 2003. The microchip passed the first stages of live testing in 2004 when it was used to replace a neural circuit in a slice of rat brain tissue kept alive in a dish. Theodore Berger of the University of Southern California hopes this silicon chip implant will perform the same processes as the damaged part of the brain it's replacing. This prosthetic could eventually help people who suffer brain damage due to stroke, epilepsy or Alzheimer's disease.