OLDS AND THE PLEASURE CIRCUIT
James Olds (1922-1976) completed his doctoral research in yoga poses psychology with Peter Milner at McGill University in yoga poses Montreal. Their professor, Donald Olding Hebb (1904-1985),115 asked them to see if they could find, outside of the thalamus and the hypothalamus, limbic zones associated to affective responses. They explored the zone situated around the thalamus, between the pituitary (the bottom of the limbic system) and the septum (the top of the limbic system). These two centers form an axis that passes vertically by the thalamus. By chance, Olds and his collaborators found a zone of the rhinencephalic structures, strongly associated to the sense of smell, that created a sensation of pleasure each time it was stimulated. It became possible to condition rats by activating this zone, as Pavlov and Skinner did by giving food as a reward. For example, Olds activated the electrode every time the rat walked in yoga poses a corner of its cage. After a while, the rat visited that corner of the cage more and more frequently.
To deepen his understanding of this phenomenon, Olds connected the electrode to a lever that could be activated by the rat. The rat could freely press on this lever at any time. Most of the rats developed an addiction to this behavior. They pressed on the lever more than 500 times per hour. If the experimenter disconnected the electrode, after half an hour, the rat pressed on the lever for a moment and then fell asleep, exhausted. If the experimenter did not disconnect the electrode, the rat ignored his basic needs (hunger and thirst) and pressed on the lever up to 2,000 times per hour for 24 hours. Some rats pressed on the lever until they died.
The same technique was used to help patients who were seriously troubled (schizophrenia, epilepsy). The behaviorist point of view regarding these treatments was to be able to teach patients to execute certain tasks with pleasure. These patients used words like relaxing, joy, or ecstasy to describe what they felt but were unable to explain why they felt the compulsive need to press the button.
These results show several interesting things relative to internal propensities:
1. It is possible to distinguish the difference between the need to eat and the pleasure in yoga poses eating. Olds observes that when a rat feels pleasure, it no longer has to eat. The pleasure in yoga poses eating connects two distinct mechanisms:
1a. A propensity, when it is activated, becomes imperialistic. Not only does it mobilize the whole of the resources of the organism, but it also inhibits the other propensities.
1b. The pleasure principle does not by itself ensure the survival of the organism.
2. The impact of conditioning varies from one individual to another, even among rats. Certain individuals let themselves be had more easily than others.
3. Some human adults with whom Olds used this device can perceive themselves as having pleasure in yoga poses pushing a lever, but they are not aware that they have conditioned themselves to press the button. They always have the impression that they make the decision to act. This shows that conditioning remains nonconscious, even when the behavior that it unleashes can be detected consciously. This observation is close to that described by hypnotists.
At the beginning, Olds was still influenced by the notion of cerebral localization, given that he speaks of the pleasure center. But after ten years of research,116 he shows that the septum is part of a circuit of pleasure that connects a center situated in yoga poses front of the neocortex (prefrontal cortex) to other zones of the limbic system like the amygdala and the ventral tegmental area (VTA). This neurological circuit is also associated to the dopaminergic system It plays an important role in yoga poses conditioning.117 The pleasure circuit is also associated to hormones of the catecholamine family, like norepinephrine.118 Olds thus rejoins the point of view concerning the circuits defended by some of