When Talking Ends – Psychogenic Amnesia and the Brain
For many years “dissociated” from neuroscientific arena, dissociative (psychogenic) amnesia – a condition usually characterized by severe retrograde memory impairment in the absence of brain damage as detected by conventional structural imaging techniques – has recently received increased attention in neuroscientific and interdisciplinary talks. Across various cultures, dissociative amnesia is nowadays recognized to occur in relationship to psychological trauma or stress. Dissociative amnesia can lead to significant and at times chronic impairments of the autonoetic consciousness, self, social functioning, and mental time travel, trapping a potentially linguistically sophisticated person in a so-called noetic existence. The exact mechanisms through which psychological stress affects mnemonic processing in dissociative amnesia are not fully elucidated, but studies emphasize the role of gene-environment interplays during windows of vulnerability in mediating the impact of stressful events on brain structures, which are crucial for memory processing. We and other research groups have investigated patients with dissociative (psychogenic) amnesia by extensive neuropsychological testing as well as functional and occasionally newer structural brain imaging techniques. In a relatively large sample of patients with this condition we evidenced hypometabolism during resting state in the right temporo-frontal region, with a decrease in the infero-lateral prefrontal cortex. In our opinion, this finding reflects the stress-mediated impairment of the episodic-autobiographical memory retrieval. It is congruent with our idea that dissociative (psychogenic) amnesia results from a stress-mediated disruption of the normal “talking” (connectivity) between brain structures of the memory network, in particular due to a desynchronization during retrieval between processing of affect-laden events (assumed to preferentially engage the right hemisphere) and fact-processing (assumed to engage the left hemisphere).
Angelica Staniloiu obtained her medical degree in 1992 from the University of Medicine and Pharmacy Carol Davila, Bucharest. After receiving her training in psychiatry at Boston University Medical Center and at the University of Toronto’s psychiatric residency program, she completed a clinical fellowship in psychopharmacology and cognitive-behavioral therapy in mood disorders at the University of Toronto (2002–2003). She is board certified in psychiatry by the Royal College for Physicians and Surgeons of Canada and the American Board for Psychiatry and Neurology. Between 2003 and 2008 she was a staff psychiatrist in the Mood and Anxiety Disorders Clinic at the Centre for Addiction and Mental Health, Toronto and a lecturer in the Department of Psychiatry at the University of Toronto. Since November 2008, she has been working as a research associate and lecturer in the Department of Physiological Psychology at the University of Bielefeld. Her research interests are functional amnesias, affective disorders, cultural neuroscience, epigenetics, and the neurobiological underpinnings of violent behavior.