title: Evidence for the involvement of extinction-associated inhibitory learning in the forced swimming test.
abstract: The forced swimming test (FST) remains one of the most used tools for screening antidepressants in rodent models. Nonetheless, the nature of immobility, its main behavioral measure, is still a matter of debate. The present study took advantage of our recent finding that mice of the inbred DBA/2J strain require a functioning left dorsolateral striatum (DLS) to consolidate long-term memory of FST to test whether immobility is the outcome of stress-related learning. Infusion of the GABA-A agonist muscimol in the left DLS immediately after a single experience of FST prevented and infusion in the left or the right amygdala impaired recall of the acquired levels of immobility in a probe test performed 24h later. Post-training left DLS infusion of muscimol, at a dose capable of preventing retention of FST-induced immobility, did not influence 24h retention of inhibitory avoidance training or of the escape response acquired in a water T-maze. However, this same treatment prevented 24h retention of the extinction training of the consolidated escape response. These results indicate that a left DLS-centered memory system selectively mediates memory consolidation of FST and of escape extinction and support the hypothesis that immobility is the result of extinction-like inhibitory learning involving all available escape responses due to the inescapable/unavoidable nature of FST experience.
authors.affiliation: Dip. Psicologia, Center D.Bovet (CRIN), 'Sapienza' University of Rome, via dei Marsi 78, I-00185 Rome, Italy; Fondazione Santa Lucia I.R.C.C.S., Via del Fosso di Fiorano 64, I-00143 Rome, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Campus
authors.affiliation: Dip. Psicologia, Center D.Bovet (CRIN), 'Sapienza' University of Rome, via dei Marsi 78, I-00185 Rome, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Colelli
authors.affiliation: Dip. Psicologia, Center D.Bovet (CRIN), 'Sapienza' University of Rome, via dei Marsi 78, I-00185 Rome, Italy; Fondazione Santa Lucia I.R.C.C.S., Via del Fosso di Fiorano 64, I-00143 Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Orsini
authors.affiliation: Dip. Psicologia, Center D.Bovet (CRIN), 'Sapienza' University of Rome, via dei Marsi 78, I-00185 Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Sarra
authors.affiliation: Dip. Psicologia, Center D.Bovet (CRIN), 'Sapienza' University of Rome, via dei Marsi 78, I-00185 Rome, Italy; Fondazione Santa Lucia I.R.C.C.S., Via del Fosso di Fiorano 64, I-00143 Rome, Italy. Electronic address: simona.cabib@uniroma1.it.
authors.forename: S
authors.initials: S
authors.lastname: Cabib
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001245:Association Learning / Q000502:physiology*; D005108:Extinction, Psychological / Q000187:drug effects / Q000502:physiology*; D007839:Functional Laterality / Q000187:drug effects; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D051379:Mice; D008811:Mice, Inbred DBA; D009118:Muscimol / Q000494:pharmacology; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D011930:Reaction Time / Q000187:drug effects; D013550:Swimming / Q000523:psychology*
chemical_list: D058785:GABA-A Receptor Agonists; D009118:Muscimol
keywords: Animal model; Coping; Depression; Extinction; Memory consolidation; Stress