ABSTRACT
In earlier points we have made reference to an individual's window of tolerance (Siegel, 1999; Ogden et al., 2006) and the implications of an overload on the autonomic nervous system (ANS) pushing a person signi®cantly outside this window. This leads either to hyperarousal of the sympathic nervous system (SNS) or hypoarousal of the parasympathetic nervous system (PNS) with the potential to affect the normal process of remembering. Under severe conditions, when a person is faced with a traumatic, life-threatening situation, they respond with a ¯ight, ®ght or freeze response. Existing memory schemas are often unable to accommodate extremely frightening experiences, so these are stored differently and are dissociated from ordinary verbal autobiographical (declarative) memory. Normal verbal memories are processed via the hippocampus which categorizes experiences semantically in terms of space, time and context. During traumatic events the hippocampus is suppressed in the interests of a rapid response so that traumatic memories are context-free (van der Kolk et al., 1996; Rothschild, 2000). If we have the support and opportunity to process these experiences in a safe place, then we will be able to make sense of them, create a coherent narrative, integrate these experiences into the story of our lives and store these as autobiographical memories. However, if trauma is prolonged and there is ongoing stress the hippocampal suppression will remain in effect and we will be left with context-free associations, governed by the limbic system, that we cannot locate in time and space. We may therefore have amnesia for the speci®c details of the traumatic experience but still experience the encoded signals associated with the trauma as sensory ¯ashbacks, impulsive outbursts of feeling, or terrifying dreams, inter alia. We lose our capacity for affect regulation and the ability to assess danger and may respond as if to a life threat to any internal or external cues that have some vague
is going them others in response to minor provocations' (van der Kolk et al., 1996: 219). Traumatized individuals tend to react to their constant hyperarousal by shutting down and avoiding certain upsetting situations and by emotional numbing, which has a neurobiological component. Endogenous opioids that inhibit pain and reduce panic are secreted after prolonged exposure to stress. This process reduces the conscious impact of the pain but interferes with the memory storage. Post-traumatic stress disorder (PTSD) arises from extremely distressing events that have not been processed.
