A recent Dual Representation Model of intrusive memory proposes that intrusions reflect involuntary reactivation of egocentric/hippocampally dependent representations in the absence of a corresponding allocentric/hippocampally independent representation (Brewin, Gergory, Lipton, & Burgess, 20 I 0). We investigated allocentric processing, following trauma, and examined whether PTSD sufferers have impaired performance indicative of reduced hippocampal functioning. Trauma-exposed individuals with (N=29) and without a diagnosis of PTSD (N=29) completed two tests of allocentric spatial processing. The first, a topographical recognition task comprising perception and memory components. The second, a virtual environment in which objects are presented and recognition memory is tested from either the same viewpoint as presentation (tapping egocentric memory) or a different viewpoint (tapping alloeentric memory). Participants in the PTSD group performed significantly worse on both tests of allocentric spatial processing than trauma-exposed controls. Groups performed comparably on egocentric memory and a non-spatial memory task of object list learning. These results show an unambiguous impairment in hippocampally dependent cognitive processes. As predicted by the Dual Representation Theory-Revised those with PTSD display impaired allocentric processing indicative of reduced hippocampal function . The clinical and research implications of this result will be discussed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:604302 |
| Date | January 2013 |
| Creators | Smith, Kirsten V. |
| Publisher | Royal Holloway, University of London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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