Dynamics of the reorganization of an operant food-procuring response during an increase in the delay of reinforcement in monkeys.

Operant activity was studied in monkeys in a situation in which they actively initiated a frequency of pressing a lever to obtain subsequent food reinforcement. Studies addressed the dynamics of relearning when the duration of the lever holding time needed to obtain reinforcement was increased from 1 to 2.5 sec.

Some neurophysiological mechanisms of the perception of interoceptive signals.

The principal objective of this study consisted in the identification of some basic mechanisms of the perception of the interoceptive signal. The EEG activation reaction through mechanoreceptive stimulation of the stomach served as the indicator. A positive relationship was found between the intensity of the activation reaction and the intensity of the stimulus employed; the extinguishability of the reaction in response to repeatedly acting interoceptive stimuli was also found.