[Mechanisms causing repeated pedal pressing during self stimulation of the brain].

Mono- and polymodal histograms of pauses duration were obtained in rats during self-stimulation (SS) through electrodes implanted in the lateral hypothalamus. Changes in motivational state (deprivation--satiation) did not markedly affect the histogram pattern. It is concluded that the SS drive mechanism is not connected with natural motivations. In all experiments, a high negative correlation between "optimal criterion" parameters and model pause duration is obtained. It is suggested that one and the same mechanism underlies both the SS-reinforcement and drive. Reinforcement is probably connected with current excitation of reinforcing structures during stimulation, whereas the drive is caused by trace activation of the same cerebral structures after the stimulation.