Saturday, July 12, 2008

brain implants: Delgado's stimoceiver

Dr. José Manuel Rodriguez Delgado (b. 1915) was a Spanish professor of physiology at Yale University, famed for his research into electrical stimulation of regions in the brain.

Delgado was born in Ronda, Spain in 1915. He received an Doctor of Medicine degree from the University of Madrid just before the outbreak of the Spanish Civil War, in which he served as a medical corpsman on the Republican side. After the war he had to repeat his M.D. degree, and then took a Ph.D. at the Cajal Institute in Madrid.

In 1946 he began a fellowship at Yale, and was invited by the noted physiologist John Fulton to join the department of physiology in 1950.

Delgado's research interests centered on the use of electrical signals to evoke responses in the brain. His earliest work was with cats, but later did experiments with monkeys and humans.

Much of Delgado's work was with an invention he called a stimoceiver, a radio which joined a stimulator of brain waves with a receiver which monitored E.E.G. waves and sent them back on separate radio channels. This allowed the subject of the experiment full freedom of movement while allowing the experimenter to control the experiment.

The stimoceiver could be used to stimulate emotions and control behavior. According to Delgado, "Radio Stimulation of different points in the amygdala and hippocampus in the four patients produced a variety of effects, including pleasant sensations, elation, deep, thoughtful concentration, odd feelings, super relaxation, colored visions, and other responses." Delgado stated that "brain transmitters can remain in a person's head for life. The energy to activate the brain transmitter is transmitted by way of radio frequencies." (Source: Cannon; Delgado, J.M.R., "Intracerebral Radio Stimulation and recording in Completely Free Patients," in Schwitzgebel and Schwitzgebel (eds.))

The most famous example of the stimoceiver in action occurred at a Cordoba bull breeding ranch. Delgado stepped into the ring with a bull which had had a stimoceiver implanted. The bull charged Delgado, who pressed a remote control button which appeared to cause the bull to stop its charge. Delgado claimed that the stimulus caused the bull to lose its aggressive instinct; skeptics suggested that the electrical impulse had caused the bull to turn aside.

Although the bull incident was widely mentioned in the popular media, Delgado believed that his experiment with a female chimpanzee named Paddy was more significant. Paddy was fitted with a stimoceiver that detected a brain signal called a spindle. When a spindle was detected, the stimoceiver responded with a signal to the central gray area of Paddy's brain, producing an 'aversive reaction'. Within hours her brain was producing many fewer spindles.

In 1974, Delgado returned to Spain to help organize a new medical school at the Autonomous University of Madrid.

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