Disruption of fear memory consolidation and reconsolidation by actin filament arrest in the basolateral amygdala

Neurobiol Learn Mem. 2010 Sep;94(2):117-26. doi: 10.1016/j.nlm.2010.04.007. Epub 2010 Apr 21.


The dynamic re-arrangement of actin filaments is an essential process in the plasticity of synaptic connections during memory formation. In this study, we determined in mice effects of actin filament arrest in the basolateral complex of the amygdala (BLA) at different time points after memory acquisition and re-activation, using the fungal cytotoxin phalloidin. Our data show a selective disruption of auditory cued but not contextual fear memory, when phalloidin was injected 6h after conditioning. In contrast, no effect was observed when phalloidin was applied after 24h, ruling out an interference with the retrieval or expression of conditioned fear. A comparable result was obtained after memory re-activation, hence suggesting similar actin-dependent mechanisms to be active during consolidation and reconsolidation of auditory fear memory. Biochemical analysis showed that phalloidin-mediated filament arrest leads to a transient increase of highly cross-linked actin filaments in the BLA, evident 2h after injection. Together, these observations indicate that dynamic re-arrangements of actin filaments in the BLA during a late phase of fear memory consolidation and reconsolidation are critical for fear memory storage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustic Stimulation
  • Actins / drug effects
  • Actins / metabolism*
  • Amygdala / drug effects
  • Amygdala / metabolism*
  • Analysis of Variance
  • Animals
  • Avoidance Learning / drug effects
  • Avoidance Learning / physiology*
  • Conditioning, Classical / drug effects
  • Conditioning, Classical / physiology*
  • Cytotoxins / pharmacology
  • Exploratory Behavior / drug effects
  • Exploratory Behavior / physiology
  • Fear
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neuronal Plasticity / drug effects
  • Neuronal Plasticity / physiology
  • Phalloidine / pharmacology
  • Retention, Psychology / drug effects
  • Retention, Psychology / physiology*
  • Time Factors


  • Actins
  • Cytotoxins
  • Phalloidine