Consummatory Successive Negative Contrast in Rats: Memory Interference versus Incentive Learning

CUENYA, L.; ANNICCHIARICO, I.; SERAFINI, M.; VALDEZ, A.; GLUECK, A.; MUSTACA, A. E. ; PAPINI, M.

Bogota

Conferencia; 17th Biennial Meeting of the International Society for Comparative Psychology; 2014

International Society of Comparative Psychology

Exposing rats to a downshift from a large reward to a smaller reward leads to greater consummatory suppression than an unshifted, small-reward condition, an effect called consummatory successive negative contrast (cSNC). Does the internal deprivation state during preshift sessions determine the size of the cSNC effect during postshift sessions? Memory interference suggests that a change in internal context would interfere with memory retrieval of the preshift reward magnitude, thus reducing the cSNC effect. Incentive learning predicts that deprivation level during preshift determines incentive value independently of the postshift state. Experiments 1-2 manipulated deprivation level by introducing a 10-day interval between the last preshift and first postshift sessions during which food deprivation was either maintained or changed relative to preshift sessions. Experiments 3-4 maintained all animals at 100% of their ad lib weight during the entire experiment, but they were either fed or not fed immediately before each session. This procedure avoided the 10-day interval used in previous experiments. In 3 of the 4 experiments, the size of the cSNC effect increased when animals were deprived/not fed immediately prior to preshift sessions. The remaining experiment yielded inconclusive results. Thus, it appears that sucrose rewards are valued more highly when animals are in a relatively higher motivational state during the initial sessions of training, whether the reward downshift occurs under different or similar internal conditions relative to preshift sessions