Self Stimulation in Rats

A rat is seen in a chamber with an electrode placed in the lateral hypothalamus of its brain. Eventually, the rat presses a lever that sends a weak electrical current that stimulates the lateral hypothalamus. Once the lateral hypothalamus is stimulated, the reward system is activated, which reinforces the rat's behavior. The rat is then shown pressing the lever constantly, at the expense of other critical activities such as eating and drinking.