Ge. Schafe et Je. Ledoux, Memory consolidation of auditory Pavlovian fear conditioning requires protein synthesis and protein kinase A in the amygdala, J NEUROSC, 20(18), 2000, pp. NIL_5-NIL_9
Previous studies have shown that long-term potentiation (LTP) can be induce
d in the lateral nucleus of the amygdala (LA) after stimulation of central
auditory pathways and that auditory fear conditioning modifies neural activ
ity in the LA in a manner similar to LTP. The present experiments examined
whether intra-LA administration of inhibitors of protein synthesis or prote
in kinase A (PKA) activity, treatments that block LTP in hippocampus, inter
fere with memory consolidation of fear conditioning. In the first series of
experiments, rats received a single conditioning trial followed immediatel
y by intra-LA infusions of anisomycin (a protein synthesis inhibitor) or Rp
-cAMPS (an inhibitor of PKA activity) and were tested 24 hr later. Results
indicated that immediate post-training infusion of either drug dose-depende
ntly impaired fear memory retention, whereas infusions 6 hr after condition
ing had no effect. Additional experiments showed that anisomycin and Rp-cAM
PS interfered with long-term memory (LTM), but not short-term memory (STM),
of fear and that the effect on LTM was specific to memory consolidation pr
ocesses rather than to deficits in sensory or performance processes. Findin
gs suggest that the LA is essential for memory consolidation of auditory fe
ar conditioning and that this process is PKA and protein-synthesis dependen
t.