For over a century it has been understood that traumatic experiences can leave indelible emotional memories. Contemporary studies of how the amygdala is activated by extreme experiences dovetail with the laboratory observation that "emotional memory may be forever" (LeDoux et al., 1991). The accumulated body of research suggests that patients with PTSD suffer from impaired cortical control over subcortical areas responsible for learning, habituation, and stimulus discrimination. Hence, current thinking is that indelible subcortical emotional responses are held in check to varying degrees by cortical and hippocampal activity, and that delayed onset PTSD is the expression of subcortically mediated emotional responses that escape cortical, and possibly hip-pocampal, inhibitory control (van der Kolk and van der Hart, 1991; Pitman et al., 1990; Shalev et al., 1992).
The early neuroimaging studies of PTSD showed that, during exposure to a traumatic script, there was decreased Broca's area functioning and increased activation of the right hemisphere (Rauch et al., 1996). This means that it is difficult for a traumatized individual to verbalize precisely what he or she is experiencing, particularly when he or she becomes emotionally aroused. It is likely that excessive physiological arousal plays a role in the failure to "process" the trauma, causing fragments of memories to be activated in response to traumatic reminders. These activate neural networks that contain the "memory" of the traumatic event, that is, the sensations and emotions related to the trauma, often without much verbal or symbolic representation of the event: When a traumatic memory is activated, the brain is "having" its experience, rather than recollecting it.
A relative decrease in left-hemispheric activation during the reliving of the trauma (Rauch et al., 1996; Teicher et al., 2002) explains why traumatic memories often are experienced as timeless and ego-alien: The part of the brain necessary for generating sequences and for the cognitive analysis of experience (the dorsolateral prefrontal cortex) is not properly activated (Lanius et al., 2001). An individual may feel, see, or hear the sensory elements of the traumatic experience, but he or she may be physiologically prevented from being able to translate this experience into communicable language. During flashbacks, victims may suffer from speechless terror in which they may be literally "out of touch with their feelings." Physiologically, they may respond as if they are being traumatized again. Particularly when victims experience depersonalization and derealization, they cannot "own" what is happening and thus cannot take steps to do anything about it.
In order to help traumatized individuals process their traumatic memories, it is critical that they gain enough distance from their sensory imprints and trauma-related emotions so that they can observe and analyze these sensations and emotions without becoming hyperaroused or engaging in avoidance maneuvers. The serotonin reuptake blockers seem to be able to accomplish exactly that. Studies in our laboratory have shown that SSRIs can help PTSD patients gain emotional distance from traumatic stimuli and make sense of their traumatic intrusions (van der Kolk et al., 1995).
The apparently relative decrease in left-hemisphere activation while reexperienc-ing the trauma suggests that it is important to help people with PTSD find a language in which they can come to understand and communicate their experiences. It is possible that some of the newer body-oriented therapies, dialectical behavior therapy, or EMDR (Chemtob et al., 2000; van der Kolk, 2002) may yield benefits that traditional verbally based therapies may lack because they do not require that the victim be able to verbally communicate the details of his or her experience.
Research has shown that making meaning—by simply talking about the traumatic experiences—is usually not enough to help people put their emotional responses behind them. Traumatized individuals need to have experiences that directly contradict the emotional helplessness and physical paralysis that accompany traumatic experiences
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