Malleable Memories of Fear

Abstract

The recall of a memory by a reminder stimulus places this memory back into an active and labile state, from which it is reconsolidated into an inactive and stable state. Is this cellular reconsolidation of memory simply a recapitulation of the events engaged at consolidation, or is there a more complicated process at work (see the Perspective by Izquierdo and Cammarota)? Lee et al. show that brain-derived neurotrophic factor (BDNF), but not transcription factor Zif268, is necessary for the consolidation of contextual fear conditioning within the hippocampus. However, Zif268, but not BDNF, is required for reconsolidation of the contextual fear memory. Frankland et al. show that processing fear memories involves the activation of multiple cortical regions of the brain. Cortical activation was greater after remote, rather than recent, memory tests, which is consistent with an increasingly important role for the cortex over time. The anterior cingulate cortex, an area involved in processing contextual or emotional memories, played a critical role in remote memory for contextual fear conditioning. I. Izquierdo, M. Cammarota, Zif and the survival of memory. Science 304 , 829-830 (2004). [Summary] [Full Text] J. L. C. Lee, B. J. Everitt, K. L. Thomas, Independent cellular processes for hippocampal memory consolidation and reconsolidation. Science 304 , 839-843 (2004). [Abstract] [Full Text] P. W. Frankland, B. Bontempi, L. E. Talton, L. Kaczmarek, A. J. Silva, The involvement of the anterior cingulate cortex in remote contextual fear memory. Science 304 , 881-883 (2004). [Abstract] [Full Text]