Insular cortex and consummatory successive negative contrast in the rat.
Rats that are expecting a high value reward (e.g., 1.0 M sucrose) show an exaggerated underresponding when they are instead given a low value reward (e.g., 0.15% saccharin), an effect termed successive negative contrast (SNC). In the present experiment, insular cortex-lesioned (ICX) rats showed normal responsivity to sucrose and saccharin prior to the reward downshift. However, when switched from sucrose to saccharin during the postshift trials these rats displayed no evidence of SNC. Indeed, over the downshift trials these ICX rats consistently drank more saccharin than the ICX rats maintained on saccharin throughout the experiment. Potential interpretations are discussed including a lesion-induced impairment in the ability to accurately recognize the novelty of the postshift saccharin stimulus.
Lin
Jian-You
JY
Department of Psychology, University of Illinois at Chicago, Chicago, IL 60607, USA.
Roman
Christopher
C
Reilly
Steve
S
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D003216:Conditioning, Operant / Q000502:physiology; D019422:Dietary Sucrose / Q000008:administration & dosage; D008297:Male; D016202:N-Methylaspartate / Q000633:toxicity; D010296:Parietal Lobe / Q000293:injuries / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward; D012439:Saccharin / Q000008:administration & dosage; D013702:Temporal Lobe / Q000293:injuries / Q000502:physiology*; D013997:Time Factors
D019422:Dietary Sucrose; D016202:N-Methylaspartate; D012439:Saccharin