BIOLOGICAL BASES OF DISSOCIATIVE AMNESIA
Journal Title: Acta Neuropsychologica - Year 2017, Vol 15, Issue 1
Abstract
Dissociative amnesia is defined as the retrograde memory loss in the absence of detectable structural brain damage caused by disassociation. Although the classification criteria of dissociative amnesia are based solely on the clinical image and do not refer to biological mechanisms, recent neurobiological studies using applied modern brain imaging techniques suggest that biological mechanisms play a crucial role in this disorder. Research on this phenomenon indicated that the main biological factors that trigger dissociative amnesia are an excessive arousal of the prefrontal cortex, hippocampus and amygdalae. The prefrontal cortex is a structure, which integrates internal and external experience. In the case of an excessive arousal, its functions become deregulated, which results in the inability to register the received stimuli. The hippocampus is a very flexible structure, yet highly vulnerable. As a result of the exposure to stress factors, stress hormones are secreted, which leads to an arousal of the hippocampus. Too rapid or too long secretion of stress hormones may lead to an excessive arousal of the hippocampus, which may then lead to hippocampus damage. Meanwhile, the amygdalae primarily regulate the intensity of an emotional reaction to a traumatic event, and hence affect the arousal of other brain structures. Yet, individual differences in the predisposition to the occurrence of dissociative amnesia might be an important factor in developing this disorder; such as the predisposition to overreact to distressing factors. As a result, current research indicates that neurobiological mechanisms at least partially explain mechanisms of dissociative amnesia. Nevertheless,despite the recent progress in the identification of the biological mechanisms underlying this disorder, the research cannot be considered as completed and further investigation is needed.
Authors and Affiliations
Monika Bidzan
Keywords
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