The Psychobiology of Traumatic Memory Clinical Implications of Neuroimaging Studies z BESSEL A. VAN DER KOLK, JENNIFER A. BURBRIDGE, AND JOJI SUZUKI All these intrusive recollections only have an experiential quality to them: When I have these flashbacks they are not explainable, I can’t make things sequential. Up till now they had very little outline to them. Now a tiny fraction of these torture experiences have become knowable to me, but when I come closer to them and stop warding them off, I zyxwv start having all sorts of problems of a different kind: I become confused, I lose things and zyxw start getting into accidents. The tragedy is the loneliness: the inability to convey the inner experience, and knowing that I cannot get out of it without going through it again. zyxw A patient with PTSD recounting her traumatic memories William James noted that the power of the intellect is determined by the individual’s perceptual processing style. The ability to comprehend (grasp, hold together, take hold of, from the Latin zyxwvu cum-prendere) depends on stimulus sampling, bias, and the formation of schematic representations of reality.’ There seem to be qualitatively significant differences between the ways persons with posttraumatic stress disorder (PTSD) sample, bias, and categorize experience, and the ways in which nontrauma- tized persons do.2*’ In recent years, systematic research has begun to confirm the clinical observation that failure to comprehend the experience (i.e., to dissociate) plays a critical role in making a stressful experience traumatic. Dissociation causes memories of the trauma to be organized, at least initially, as sensory fragments and intense emotional states that may have no linguistic components. This fragmentation is accompanied by subjective experiences of depersonalization and dereali~ation.~ Whereas most patients with PTSD construct a narrative of their trauma over time, it is characteristic of PTSD that sensory elements of the trauma itself continue to intrude as flashbacks and nightmares, altered states of consciousness in which the trauma is relived, unintegrated with an overall sense of self. Because traumatic memories are so fragmented, it seems reasonable to postulate that extreme emotional arousal leads to failure of the central nervous system (CNS) to synthesize the sensa- tions related to the trauma into an integrated whole. Earlier models for a biological substrate of these phenomena have become rapidly outdated with the availability of new information derived from neuroimaging studies of patients with PTSD. The emerging body of knowledge from these studies has stimulated a gradual shift in emphasis away from the neurochemicals involved in the organisms’ response to overwhelming threat to a focus on the neuronal filters concerned in the interpretation of sensory information: the interactions between the various parts of the CNS that process and interpret the meaning of incoming information, such as the amygdala, hippocampus, corpus callosum, anterior cingulate, and prefrontal cortex. zy 99