Figure 6.

Mean consumption (±SEM]; panels A,C) and mean lick cluster size [LCS: panels B,D (±SEM) as a function of concentration. This test involves single solution presentations only and thereby removes the anticipatory element of the previous contrast studies. Wistar rats are shown in the upper panels (A,B), WKY rats in the lower panels (C,D). For consumption, WKY rats drank significantly less than Wistar rats, and stressed rats consumed significantly less than no-stress rats, but these factors did not interact (see “Consumption of 2, 8, and 32% Sucrose” section for details). While both WKY and Wistar rats displayed increasing lick cluster size with concentration increases (reflecting the higher palatability of more concentrated solutions), these effects were significantly smaller in WKY rats, which also displayed lower lick cluster size overall: a pattern of effects that is consistent with a partially preserved but extremely blunted hedonic responses in WKY rats (see “Lick Cluster Size for 2, 8, and 32% Sucrose” section for details).