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DIGITAL PEOPLE

programmable in the 1970s; that is, their pulse rates could be exter- nally altered by radio signals without additional surgery. Recent mod- els are rate responsive, meaning they detect the implantees activity and adjust the pulse rate accordingly; they work at minuscule power levels, giving them extremely long lifetimes; they operate in a dual- chamber mode, meaning they use two electrical wires to pace both the upper and lower chambers of the heart, synchronizing blood flow for maximum efficiency; and they store the implantees medical infor- mation in computer memory for retrieval by a physician.

ELECTRIFYING THE MIND

At their high level of perfection, heart pacemakers represent a suc- cessful bionic intervention, but they do not involve neural connec- tions. What might be called neurobionics, however, also has a long history arising from the desire to use electricity to affect neural be- havior or alleviate certain disabilities. In the Roman era, Scribonius Largus, court physician to the emperor Claudius, reported that he could relieve the pain of headaches by placing a torpedo fish or elec- tric rayanother fish that emits an electric chargeon the sufferers forehead.Apparently, just as the fishs electric charge stunned its prey, the electricity stunned the patients nervous system to provide relief. Today electrical stimulation of the nervous system is routinely carried out using both external and implanted devices to relieve pain, and for other therapeutic purposes.

One form of electrical brain stimulation, electroshock or electro- convulsive therapy (ECT), is intended to cure mental disease. The method was conceived when it was seen that epileptic seizures seemed to relieve the symptoms of schizophrenia. By the late 1930s, the Ital- ian researchers Ugo Cerletti and Lucino Bini were learning how to induce such seizures electrically. In initial testing, they placed elec- trodes so as to send electricity through the entire body of a dog, but the shock to the animals heart proved fatal. Placing the electrodes on a dogs head, however, avoided any flow of current through the heart. In 1938, electroshock was first applied to a schizophrenic person, who

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