Applications to Traumatic Recall
This section compares PTSD and fear conditioning during consolidation. PTSD memory has limited accessibility to personally meaningful content. Its memory is characterized by increased responsiveness to perceptual triggers reminiscent of the trauma. Traumatic perceptions also have sensory flashbulb or hotspot qualities and can uncontrollably elicit a representational portion of the traumatic memory. PTSD memory is characterized by deficits in intentional and deliberate recollection, trauma narrative coherence, and temporal order.
According to the multiple memory systems model, the striatal behavioral and amygdaloid motivational stimulus-response systems and cortical perceptual system (singly and in interaction) are probably biased expression in PTSD. This response is also likely enhanced by a hyperresponsive hippocampal formation (underlying the reexperiencing of abreactions-see Osuch et al., 2001). This is in accordance with this section’s MEMORY/Multiple Memory Systems section of this web site. Neural inactivation of the striatal region in the rodent allows for hippocampal expression of place learning, which is the tendency for uncontrollably retrieving previously learned behavioral sequences (DeCoteau & Kessner, 2000; Packard & McGaugh, 1996). Hippocampal mediated reactivations in these regions can account for PTSD memory’s implicit features of involuntary perceptual reexperiencing of traumatic sensory fragments and traumatic emotion like fear as well as behavioral reliving and identifying with traumatic material. Impairments or disruptions in traumatic memory’s ability for intentional and declarative recall and retrieval of a cohesive trauma narrative suggest contextual deficits in hippocampal functional integrity. This discussion will be enhanced by examining the effects of trauma processing during exposure therapy.
References
DeCoteau, W.E., & Kesner, R.P. (2000). A double dissociation between the rat hippocampus and medial caudoputamen in processing two forms of knowledge. Behavioral Neurosci, 114(6), 1096-1108.
Osuch, E.A., Benson, B., et al., (2001). Regional cerebral blood flow correlated with flashback intensity in patients with posttraumatic stress disorder. Biol Psychiatry, 50(4), 246-253.
Packard, M.G., & McGaugh, J.L. (1996). Inactivation of hippocampus or caudate nucleus with lidocaine differentially affects expression of place and response learning. Neurobiol Learn Mem, 65(1), 65-72.