نقش سیستم نورآدرنرژیک در حافظه هیجانی

This contribution is an overview on the role of noradrenaline as neurotransmitter and stress hormone in emotional memory processing. The role of stress hormones in memory formation of healthy subjects can bear significance for the derailment of memory processes, for example, in post traumatic stress disorder (PTSD). Increased noradrenaline levels lead to better memory performance, whereas blocking the noradrenergic receptors with a betablocker attenuates this enhanced memory for emotional information. Noradrenaline appears to interact with cortisol in emotional memory processes, varying from encoding to consolidation and retrieval. Imaging studies show that confronting human subjects with emotional stimuli results in increased amygdala activation and that this activation is noradrenergic dependent. The role of noradrenaline in other brain areas, such as hippocampus and prefrontal cortex, is shortly summarized. Finally, the pros and cons of a therapeutic application of betablockers in the (secondary) prevention of PTSD will be discussed.

Almost 15 years ago, The Netherlands were shocked by an event that was unique to our history: the “Bijlmer Disaster”. In this airplane disaster, on October 4th, 1992 a Boeing 747 air freighter crashed on two apartment buildings in the southeastern part of Amsterdam, and took the lives of 43 people. This event had an enormous emotional impact and triggered all aspects that have been studied and analyzed in the psychological and medical literature about the traumatic memory processes (Brewin, 2003 and McNally, 2003). Testimonies on the event varied enormously in content and were highly debated. It is illustrative for the complexity of traumatic memories and emotional information processing. It highlights the fact that a disaster can cause a wide range of emotions that are accompanied by both physical arousal and a noticeable impact on memory. From an evolutionary point of view it seems logical that a confrontation with a stressful situation is better remembered than a neutral situation, resulting in a more adequate reaction in a similar situation. This reasoning led to a widely accepted view that the memory for emotional information is generally better than for neutral information (Cahill and McGaugh, 1998 and McGaugh, 2000). The research reviewed here, focuses specifically on the neurobiological basis of stress, emotion, arousal and their effect on memory. This contribution, studies in particular the role of noradrenaline as neurotransmitter and stress hormone in emotional memory1 processing.