Extinction partially reverts structural changes associated with remote fear memory
- Gisella Vetere1,2,
- Leonardo Restivo1,3,
- Giovanni Novembre1,
- Massimiliano Aceti2,4,
- Massimo Lumaca1 and
- Martine Ammassari-Teule1,2,5
- 1Cell Biology and Neurobiology Institute, C.N.R.-National Research Council of Italy, 00143 Rome, Italy
- 2IRCCS Santa Lucia Foundation, 00143 Rome, Italy
Abstract
Structural synaptic changes occur in medial prefrontal cortex circuits during remote memory formation. Whether extinction reverts or further reshapes these circuits is, however, unknown. Here we show that the number and the size of spines were enhanced in anterior cingulate (aCC) and infralimbic (ILC) cortices 36 d following contextual fear conditioning. Upon extinction, aCC spine density returned to baseline, but the enhanced proportion of large spines did not. Differently, ILC spine density remained elevated, but the size of spines decreased dramatically. Thus, extinction partially erases the remote memory network, suggesting that the preserved network properties might sustain reactivation of extinguished conditioned fear.
Footnotes
- Received April 14, 2011.
- Accepted June 28, 2011.
- © 2011 Cold Spring Harbor Laboratory Press