BRAIN MECHANISMS OF EMOTIONS

At the 23-d International Congress of Physiological Sciences (Tokyo, 1 965) the results of experiment brought us to a conclusion that emotion s were determined by the actual need and estimation of probability (po ssibility) of its satisfaction. Low probability of need satisfaction l eads to negative emotions actively minimized by the subject. Increased probability of satisfaction, as compared to the earlier forecast, gen erates positive emotions which the subject tries to maximize, that is to enhance, to prolong, to repeat. We named our concept the Need-Infor mational Theory of Emotions. According to this theory, motivation, emo tion and estimation of probability have different neuromorphological s ubstrate. Activating by motivatiogenic structures of the hypothalamus the frontal parts of neocortex orients the behavior to signals with a high probability of their reinforcement. At the same time the hippocam pus is necessary for reactions to signals of low probability events, w hich is typical for emotionally excited brain. By comparison of motiva tional excitation with available stimuli or their engrams the amygdala selects a dominant motivation, destined to be satisfied in the first instance. In the cases of classical conditioning and escape reaction t he reinforcement was related to involvement of the negative emotion's hypothalamic neurons while in the course of avoidance reaction the pos itive emotion's neurons being involved. The role of the left and right frontal neocortex in the appearance of positive or negative emotions depends on this informational (cognitive) functions.