FLAVOR PREFERENCE PRODUCED BY INTRAGASTRIC POLYCOSE INFUSIONS IN RATSUSING A CONCURRENT CONDITIONING PROCEDURE

Prior studies demonstrate that nondeprived rats learn to prefer a flav or (the CS+) paired with intragastric (IG) nutrient infusions over ano ther flavor (the CS-) paired with IG water infusions when the flavors are presented on alternate days. The present experiment determined if a nutrient-based preference could be established when both flavors wer e concurrently available. Adult female rats were fitted with two chron ic gastric catheters and were given ad lib access to chow and two flav ored solutions (a bitter sucrose octaacetate solution and a sour citri c acid solution). Using an automated infusion system, consumption of t he CS+ flavor was paired with IG infusions of 32% Polycose, and consum ption of the CS- flavor was paired with IG infusions of water. Seven o f the eight rats tested developed a strong flavor preference for the C S+ over the CS-; their CS+ preference increased from 53% on day 1 to 9 5% on day 8. (The remaining animal eventually displayed a 97% CS+ pref erence after it received one-bottle training with the CS flavors.) Dur ing the first several days of training, the rats tended to drink prima rily one flavor per day, and consumed primarily one flavor per drinkin g bout. This provided them with relatively discrete flavor-consequence experiences that presumably facilitated flavor preference conditionin g.