Video 1(19 sec.) In this experiment, the rat learns to push a lever in order to introduce a rewarding stimulus by means of electrical stimulation of certain poits of the brain which cause pleasure. Each blinking of the yellow light shows that a stimulation has been delivered. In this way, Olds was able to demonstrate the existence of specific pleasure centers in the brain. Video 2(8 sec.) Here you will see a rat learning how to push a lever situated at one end of a long cage, in order to deliver an electrical stimulus to its brain pleasure center. Then, the rat must cross through an electrified grid in the cage's floor, in order to press another self-stimulation leverr at the other end. The rat endures a strong painful electric shock to its paws to cross the cage and get the stimulation. Normal rats, even when very hungry, will not do this to get food. Video 3(13 seg.) This rat is dependent on morphine. It has learned to get a drop of it every time a lever is pressed. This behavior is repeated continuously and ever so stronger, in a way similar to the brain self-stimulation.  See also in this issue: The Brain Reward System, Drugs and Society The Reward Defficiency Syndrome Drug Abuse   Extracted and abridged from original films by James Olds, University of Michigan, Michigan, 1962 Coordination and creation: Dr. Silvia Helena Cardoso, Editora-in-Chief, Brain & Mind Video capture: Gisele Felippe Rodrigues, webmaster, Center for Biomedical Informatics, State University of Campinas.  RealVideo server: Courtesy of WebPraxis International Brain & Mind Magazine 3(8), Jan/March 1999 An Initiative of the Center for Biomedical Informatics Copyright (c) 1998 State University of Campinas, Brazil Published on 18/Jan/1998 URL: http://www.epub.org.br/cm/n08/doencas/drugs/videorat_i.htm sabbatin@nib.unicamp.br