Intrusive images in psychological disorders: characteristics, neural mechanisms, and treatment implications

Abstract

Involuntary images and visual memories are prominent in many types of psychopathology. Patients with posttraumatic stress disorder, other anxiety disorders, depression, eating disorders, and psychosis frequently report repeated visual intrusions corresponding to a small number of real or imaginary events, usually extremely vivid, detailed, and with highly distressing content. Both memory and imagery appear to rely on common networks involving medial prefrontal regions, posterior regions in the medial and lateral parietal cortices, the lateral temporal cortex, and the medial temporal lobe. Evidence from cognitive psychology and neuroscience implies distinct neural bases to abstract, flexible, contextualized representations (C-reps) and to inflexible, sensory-bound representations (S-reps). We revise our previous dual representation theory of posttraumatic stress disorder to place it within a neural systems model of healthy memory and imagery. The revised model is used to explain how the different types of distressing visual intrusions associated with clinical disorders arise, in terms of the need for correct interaction between the neural systems supporting S-reps and C-reps via visuospatial working memory. Finally, we discuss the treatment implications of the new model and relate it to existing forms of psychological therapy.

Figure 1. A schematic model of memory encoding, showing the approximate regions and pathways involved in, and the areas supporting, abstracted contextual representations (C-reps, in green) and sensory-bound representations (S-reps, in red). a: Normal encoding of a traumatic event. b: Pathological encoding of a traumatic event, showing up-regulation of S-reps, down-regulation of C-reps, and disconnection between S-reps and C-reps. Heavy lines indicate stronger representations and pathways; dashed lines, weaker representations and pathways. Note the necessarily schematic style (e.g., many pathways and regions are omitted, and Hippocampus refers to the extended hippocampal formation and its subcortical connections).

Figure 2. A schematic model of the generation of memory-related imagery, showing the approximate regions and pathways involved in, and the areas supporting, abstracted contextual representations (C-reps, in green) and sensory-bound representations (S-reps, in red). a: Deliberate visual recall. Visual imagery is driven top-down by C-reps, under the direction of the prefrontal cortex. Reactivation of S-reps is weak and depends on attention to matching details in imagery. b: Involuntary flashback of a traumatic event. Visual imagery is driven bottom-up by S-reps triggered by a situational cue and unaffected by weakly activated C-reps. Heavy lines indicate stronger representations and pathways; dashed lines, weaker representations and pathways. Note the necessarily schematic style (e.g., many pathways and regions are omitted, and Hippocampus refers to the extended hippocampal formation and its subcortical connections).