This study was conducted to evaluate the effects of the variations of water availability through the manipulation of Ť values, under different signaling conditions of subcycles, maintaining constant the water delivery probability (P). Data from this study show that in some rats were observed an increase in the frequency response associated with varying Ť. There were no systematic effects related to signals in subcycles. We analyze the functional difference between P and Ť and its relationship with the frequency and temporal distribution of response