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Methods of studying the brain: A brief history. First… a few more basic facts about your brain!. Approximately 3 lbs.; slightly larger than size of an adult fist 2% of total body weight; burns 70% of your body ’ s glucose 100 billion+ neurons; trillions of synapses
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First… a few more basic facts about your brain! • Approximately 3 lbs.; slightly larger than size of an adult fist • 2% of total body weight; burns 70% of your body’s glucose • 100 billion+ neurons; trillions of synapses • Biochemical signals travel at 220 mph • Half of the 30,000 genes are dedicated to the nervous system • The brain itself feels no pain, but registers it from everywhere else
Early 1800s • Phrenology: measuring the bumps on peoples’ heads • They were wrong about bumps; right about the brain having localized functions! • http://www.bc.edu/bc_org/avp/cas/fnart/phrenology/phrenology_frames.html
1848: Phineas Gage http://youtu.be/9QXI_BxlY7M
1930s: Prefrontal lobotomies • Dr. Walter Freeman: surgical disconnection of the frontal lobes from the thalamus with an icepick • Eliminated severe behavioral problems; also took away emotions, problem solving, thinking • By 1949, 5,000 done annually • http://www.pbs.org/wgbh/americanexperience/films/lobotomist/ • http://youtu.be/_0aNILW6ILk
1950s: Electrical Stimulation of the Brain 1954: James Olds and Peter Milner placed an electrode in the hypothalamus of the brains of rats by mistake and discovered the pleasure center of the brain • When the rats learned that they could control the electrical stimulation by pressing a lever, they pressed it 7,000 times an hour (endorphins). • http://accidentalmind.org/the_discovery_of_brain_plea.html • 1969: Jose Delgado’s “matador” experiment: stimoceiver • http://wireheading.com/matador.html
Selective lesioning • Selectively damaging parts of the brain using electrical instrument • Only used in animals… obviously. • Rat hypothalamus study • Accidents and brain damage are often studied in human beings.
And now… For modern technology!