Activation of Thalamo-Cortical Systems in Post-Traumatic Flashbacks: A Positron Emission Tomography Study

Abstract

Trauma victims with post-traumatic stress disorder (PTSD) often experience ‘flashbacks’ that are described as being different from memories of other fearful biographic situations. We used Positron Emission Tomography and Statistical Parametric Mapping to compare in the same subject brain activation patterns during induced flashbacks with recall of fearful non-traumatic situations. During fearful recall there were significant activations of right precuneus. When traumatic memories were compared to neutral, right lingual gyrus, right thalamus / mamillary bodies, and right cerebellum were significantly activated. When brain activation during flashbacks was compared to simple fear, right mediodorsal thalamus (MD), right precuneus, and right cerebellum were significantly more active. With respect to recent experimental evidence concerning the function of thalamo-cortical systems, we hypothesize that post-traumatic flashback experiences are based on hyperactive thalamo-cortical ‘closed loop’ networks.

Keywords

Trauma victims post-trauamtic stress disorder flashbacks Positron Emission Tomography Statistical Parameter Mapping mediodorsal thalamus thalamo-cortical systems

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