title: Learning and reconsolidation implicate different synaptic mechanisms.
abstract: Synaptic mechanisms underlying memory reconsolidation after retrieval are largely unknown. Here we report that synapses in projections to the lateral nucleus of the amygdala implicated in auditory fear conditioning, which are potentiated by learning, enter a labile state after memory reactivation, and must be restabilized through a postsynaptic mechanism implicating the mammalian target of rapamycin kinase-dependent signaling. Fear-conditioning-induced synaptic enhancements were primarily presynaptic in origin. Reconsolidation blockade with rapamycin, inhibiting mammalian target of rapamycin kinase activity, suppressed synaptic potentiation in slices from fear-conditioned rats. Surprisingly, this reduction of synaptic efficacy was mediated by post- but not presynaptic mechanisms. These findings suggest that different plasticity rules may apply to the processes underlying the acquisition of original fear memory and postreactivational stabilization of fear-conditioning-induced synaptic enhancements mediating fear memory reconsolidation.
authors.affiliation: Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Edward G
authors.initials: EG
authors.lastname: Meloni
authors.forename: William A
authors.initials: WA
authors.lastname: Carlezon
authors.forename: Mohammed R
authors.initials: MR
authors.lastname: Milad
authors.forename: Roger K
authors.initials: RK
authors.lastname: Pitman
authors.forename: Karim
authors.initials: K
authors.lastname: Nader
authors.forename: Vadim Y
authors.initials: VY
authors.lastname: Bolshakov
mesh_terms: D000679:Amygdala / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D005239:Fear / Q000502:physiology*; D007858:Learning / Q000502:physiology*; D008297:Male; D042282:Microdissection; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020123:Sirolimus / Q000494:pharmacology; D013569:Synapses / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D046509:Tissue Culture Techniques
chemical_list: D000900:Anti-Bacterial Agents; D009419:Nerve Tissue Proteins; C546845:mTOR protein, rat; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus