| LeDoux Lab 2009 SfN Abstracts |
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| Program#/Poster#: |
479.18/FF119 |
| Title: |
Retrieval-induced strengthening
of fear memory: Interactions with beta-adrenergic blockade |
| Location: |
South Hall A |
| Presentation Time: |
Monday, Oct 19, 2009, 2:00
PM - 3:00 PM |
| Authors: |
M. H. MONFILS1,2,
L. DIAZ-MATAIX2, D. BUSH2, J. VUJOVIC2, J. DEBIEC3, V. DOYERE4, J. E. LEDOUX5,2;
1Dept. of Psychology, Univ. of Texas At Austin, Austin, TX; 2Ctr. for Neural
Sci., 3Dept. of Psychiatry, New York Univ., New York, NY; 4Univ. Paris-Sud,
Orsay, France; 5Emotional Brain Inst., Orangeburg, NY |
| Abstract: |
Evidence suggests that previously
consolidated memories revert to a mutable state when subsequently retrieved,
and that a second cycle of protein synthesis is then required to restore
the stable condition of memories: a process termed reconsolidation. Pharmacologically
interfering with mechanisms triggered during retrieval enables the targeted
modification of memories in the lateral nucleus of the amygdala (LA). A
number of studies initially focused on attenuating fear using this paradigm,
yet recent evidence also suggests that fear memories can be strengthened
pharmacologically at the time of retrieval (e.g., Tronson et al., 2007).
We, and others, have recently shown that fear memory retrieval induces an
increase in GluR1 phosphorylation at ser845 in the LA (Monfils et al., 2009
; Ben Mamou et al., 2008). In addition, we have shown that post consolidation
retrieval induces a specific increase in short-latency synaptic efficacy
in the LA, above and beyond that induced by fear conditioning (Doyere et
al., 2007). Here, we sought to examine the effect of a retrieval trial on
the strength of a fear memory, and its susceptibility to extinction. We
show that a single retrieval trial presented 24 hours prior to a session
in which the CS was repeatedly presented (extinction) leads to a resistance
to extinguish relative to a group that did not receive a CS retrieval. We
next demonstrate that a systemic injection of propranolol at the time of
retrieval leads to a reduction in freezing (reconsolidation blockade). In
addition, propranolol administered at the time of retrieval shows an effect
on the susceptibility to extinguish 24 hours later that is dependent on
strength of conditioning. The results are discussed in the context of reconsolidation-extinction
boundaries, and their interactions in mediating fear memories’ susceptibility
to attenuation. |
| Support: |
NIH R37 MH038774 to JEL
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NIH P50 MH058911 to JEL |
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NIH R01 MH046516 to JEL
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AHFMR, NSERC, and CIHR to
MHM |
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FUL to LDM |