Memory consolidation and reconsolidation in humans: the role of the amygdala and stress hormones on emotional memories
02 / 2007 - 01 / 2010
Nederlandse Organisatie voor Wetenschappelijk Onderzoek - NWO
New memory representations are labile and can be forgotten. However, once it has gone through a process called consolidation, the memory trace becomes more stabilized. Extensive scientific evidence shows that emotional arousal can strengthen memory trace. Surprisingly, new research has suggested that when a consolidated memory trace is reactivated through retrieval, this trace is rendered labile again. In order for the retrieved memory trace to become stable again, it seems to undergo another round of consolidation: reconsolidation. Animal research on emotional memory has shown that the release of stress hormones (in particular, the adrenergic hormones) modulated through the amygdala play a crucial role for both consolidation and reconsolidation. It is still unknown to what extent the animal findings apply to humans. The aim of this study is to investigate the interplay between the amygdala and the hippocampus in humans during consolidation and reconsolidation of memory with emotional context. Brain activity will be measured during encoding of episodes with and without emotional context. The brain activity during subsequent retrieval sessions will then be measured as they stabilize with consolidation. With a special focus on the amygdala, I will characterize the brain networks engaged in encoding and consolidation of memories with and without emotional context. I hypothesize that the activation of the amygdala will correlate with emotional context and enhance consolidation. The next step looks into the reconsolidation process. By reactivating the memory trace, I aim to modify the reconsolidation process through administration of propranolol, a beta-adrenergic antagonist. I hypothesize that the drug will interfere with the modulation of amygdala activity, reducing the emotional context at the reconsolidation phase. Emotionally traumatic experiences can result in severe psychiatric disorders such as post-traumatic stress disorder (PTSD). Outcome of this project will shed light on the treatment of memory disturbances in such patients.