Memory extinction, learning anew, and learning the new: dissociations in the molecular machinery of learning in cortex.
The rat insular cortex (IC) subserves the memory of conditioned taste aversion (CTA), in which a taste is associated with malaise. When the conditioned taste is unfamiliar, formation of long-term CTA memory depends on muscarinic and beta-adrenergic receptors, mitogen-activated protein kinase (MAPK), and protein synthesis. We show that extinction of CTA memory is also dependent on protein synthesis and beta-adrenergic receptors in the IC, but independent of muscarinic receptors and MAPK. This resembles the molecular signature of the formation of long-term memory of CTA to a familiar taste. Thus, memory extinction shares molecular mechanisms with learning, but the mechanisms of learning anew differ from those of learning the new.
Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel.
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Berman
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Dudai
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D002540:Cerebral Cortex / Q000378:metabolism / Q000502:physiology*; D003213:Conditioning, Psychological; D005108:Extinction, Psychological / Q000502:physiology*; D007858:Learning / Q000502:physiology*; D018021:Lithium Chloride / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D008297:Male; D008568:Memory / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D018727:Muscarinic Antagonists / Q000494:pharmacology; D014176:Protein Biosynthesis; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D012054:Reinforcement, Psychology; D012439:Saccharin; D013649:Taste
D000319:Adrenergic beta-Antagonists; D018727:Muscarinic Antagonists; D011500:Protein Synthesis Inhibitors; D011943:Receptors, Adrenergic, beta; D011976:Receptors, Muscarinic; D016194:Receptors, N-Methyl-D-Aspartate; D000841:Anisomycin; D020928:Mitogen-Activated Protein Kinases; D012439:Saccharin; D018021:Lithium Chloride