title: Rewarding effects of electrical stimulation of the insular cortex: decayed effectiveness after repeated tests and subsequent increase in vertical behavioral activity and conditioned place aversion after naloxone administration.
abstract: The insular cortex has been associated with various aversive and rewarding sensory, regulatory, and learning processes. The objective of this study was to examine the characteristics of the reinforcement induced by electrical stimulation of this brain area in rats. Results obtained confirm that electrical stimulation of the insular cortex may induce conditioned place and flavor preferences but the learning acquired is not transferred in a reversal test. Unexpectedly, they also demonstrate that this rewarding effect diminishes after repeated tests. In follow-up experiments, locomotor activity tests revealed an increased number of rearings (a sensitization index) in stimulated animals. Furthermore, in these same animals, administration of low doses of naloxone, an opiate antagonist, developed place aversion toward the maze compartment for which the animals had previously shown preference. These results are interpreted in relation to the effects induced by the repeated administration of natural and artificial rewarding stimuli.
authors.affiliation: Department of Psychobiology, University of Granada, Granada 18071, Spain. Electronic address: raquelgp@ugr.es.
authors.forename: Raquel
authors.initials: R
authors.lastname: García
authors.affiliation: Department of Psychobiology, University of Granada, Granada 18071, Spain.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Zafra
authors.affiliation: Department of Psychobiology, University of Granada, Granada 18071, Spain.
authors.forename: Amadeo
authors.initials: A
authors.lastname: Puerto
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology*; D004558:Electric Stimulation; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D009043:Motor Activity; D009270:Naloxone / Q000008:administration & dosage; D009292:Narcotic Antagonists / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar; D012054:Reinforcement, Psychology; D012201:Reward; D012653:Self Stimulation; D013649:Taste / Q000502:physiology
chemical_list: D009292:Narcotic Antagonists; D009270:Naloxone
keywords: Electrical brain stimulation; Flavor preference; Insular cortex; Naloxone; Place preference