Fear and safety learning differentially affect synapse size and dendritic translation in the lateral amygdala

Linnaea E. Ostroff, Christopher K. Cain, Joseph Bedont, Marie H. Monfils, Joseph E. LeDoux

Research output: Contribution to journalArticlepeer-review


Fear learning is associated with changes in synapse strength in the lateral amygdala (LA). To examine changes in LA dendritic spine structure with learning, we used serial electron microscopy to reconstruct dendrites after either fear or safety conditioning. The spine apparatus, a smooth endoplasmic reticulum (sER) specialization found in very large spines, appeared more frequently after fear conditioning. Fear conditioningwasassociated with larger synapses on spines that did not contain a spine apparatus, whereas safety conditioning resulted in smaller synapses on these spines. Synapses on spines with a spine apparatus were smaller after safety conditioning but unchanged with fear conditioning, suggesting a ceiling effect. There were more polyribosomes and multivesicular bodies throughout the dendrites from fear conditioned rats, indicating increases in both protein synthesis and degradation. Polyribosomes were associated with the spine apparatus under both training conditions. We conclude that LA synapse size changes bidirectionally with learning and that the spine apparatus has a central role in regulating synapse size and local translation.

Original languageEnglish (US)
Pages (from-to)9418-9423
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number20
StatePublished - May 18 2010


  • Dendritic spine
  • Fear conditioning
  • Lateral amygdala
  • Polyribosome
  • Spine apparatus

ASJC Scopus subject areas

  • General


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