Steady potential correlates of positive reinforcement: reward contingent positive variation.

A positive reinforcement with food produced high-voltage bursts of alpha activity over the posterior marginal gyrus in a cat deprived of food and water. This synchronization was always associated with a large (180 to 300 microvolt), positive steady potential shift comparable to that occurring during the onset of sleep. Since this shift was contingent upon the relative appropriateness and desirability of food reward, it was termed reward contingent positive variation.