Impaired allocentric spatial processing in posttraumatic stress disorder.

Smith KV., Burgess N., Brewin CR., King JA.

A neurobiological dual representation model of PTSD proposes that reduced hippocampus-dependent contextual processing contributes to intrusive imagery due to a loss of control over hippocampus-independent sensory and affective representations. We investigated whether PTSD sufferers show impaired allocentric spatial processing indicative of reduced hippocampal functioning. Trauma-exposed individuals with (N=29) and without (N=30) a diagnosis of PTSD completed two tests of spatial processing: a topographical recognition task comprising perceptual and memory components, and a test of memory for objects' locations within a virtual environment in which the test is from either the same viewpoint as presentation (solvable with egocentric memory) or a different viewpoint (requiring allocentric memory). Participants in the PTSD group performed significantly worse on allocentric spatial processing than trauma-exposed controls. Groups performed comparably on egocentric memory and non-spatial memory for lists of objects. Exposure to repeated incident trauma was also associated with significantly worse spatial processing in the PTSD group. Results show a selective impairment in allocentric spatial processing, implicating weak hippocampal functioning, as predicted by a neurobiological dual representation model of PTSD. These findings have important clinical implications for cognitive therapy.

DOI

10.1016/j.nlm.2015.01.007

Type

Journal article

Journal

Neurobiol Learn Mem

Publication Date

03/2015

Volume

119

Pages

69 - 76

Keywords

Allocentric memory, Hippocampus, PTSD, Spatial memory, Trauma, Adolescent, Adult, Aged, Female, Hippocampus, Humans, Male, Middle Aged, Recognition, Psychology, Space Perception, Spatial Memory, Stress Disorders, Post-Traumatic, Young Adult

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