Neurobiology of Recovered Memories and Traumatic Stress

Neural mechanisms in dissociative amnesia for childhood abuse: Relevance to the current controversy surrounding the “false memory syndrome.” (Bremner et al., 1996)
Impact: The studies reviewed here show that extreme stress has long-term effects on memory. Neuropeptides and neurotransmitters released during stress can modulate memory function, acting at the level of the hippocampus, amygdala, and other brain regions involved in memory. Such release may interfere with the laying down of memory traces for incidents of childhood abuse. Also, childhood abuse may result in long-term alterations in the function of these neuromodulators. These findings may provide a model for understanding the mechanisms involved in dissociative amnesia, as well as a rationale for phenomena such as delayed recall of childhood abuse.

Functional neuroanatomical correlates of the effects of stress on memory. (Bremner, Krystal, & Charney, 1995)
Impact: The findings discussed in this paper are consistent with the formulation that stress-induced alterations in brain regions and systems involved in memory may underlie many of the symptoms of PTSD, as well as dissociative amnesia, seen in survivors of traumatic stress.

The neurology of traumatic “dissociative” amnesia: commentary and literature review. (Joseph, 1999).
Impact: The study concludes that although some victims may be unable to forget, amnesia or partial memory loss is not uncommon following severe stress and emotional trauma. Memory loss is a consequence of glucocosteroids and stress-induced disturbances involving the hippocampus, a structure which normally plays an important role in the storage of various events in long-term memory.

Can the Neural Basis of Repression Be Studied in the MRI Scanner? New Insights from Two Free Association Paradigms. (Schmeing et al., 2013). Full Text.
Impact: Two experiments find high autonomic arousal during free association predicts subsequent memory failure, accompanied by increased activation of conflict-related and deactivation of memory-related brain regions. Results are consistent with the hypothesis that during repression, explicit memory systems are down-regulated by the anterior cingulate cortex.