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Behavioral Neuroscience

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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.


Copyright © 2009 American Psychological Association.

This is a post-print version of an article originally published in Behavioral Neuroscience, 2009, Volume 123, Issue 4.

. The version of record is available through: American Psychology Association.

"This article may not exactly replicate the final version published in the APA journal. It is not the copy of record."