Electrophysiological analysis of the conditioned reflex activity of cats during thirst.

The EEG of the cerebral cortex and the electrohypothalamogram (EHG) was recorded in cats with a salt load and water deprivation during the performance of runs conditioned to non-salty and salty food signals. The non-salty food signal against the background of thirst was accompanied only by the activation of the cerebral cortex, whereas the hypothalamus in addition to the cortex was involved in the activation in relation to the salty food signal. In those cases in which the non-salty signal was reinforced by salty food and the animal has eaten it (although it had rejected it in the presence of thirst), a strong activation of the cortex was observed, with involvement of the paraventricular divisions of the hypothalamus. The remodeling of the signal role of the conditional signals was achieved in accordance with the new quality of the food reinforcement. The hypothalamo-cortical mechanisms of the dominant motivation and its conditioned reflex effectuation are discussed.