The effect of early adversity on adult spatial cognition : a functional magnetic resonance imaging study
Master Thesis
2009
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University of Cape Town
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Exposure to traumatic childhood events can lead to a range of behavioural, psychological, and physiological consequences. Previous studies have shown that neurobiological changes in reaction to severe stress may cause lasting damage to particular neural regions, including the hippocampus and the prefrontal cortex. It has been suggested that such damage to these regions results in difficulties in associated cognitive functioning, including problems with verbal declarative memory and cognitive control. Little focus has been placed on visualspatial cognition in traumatised individuals, however. The aim of this project, which comprised two studies, was to investigate visual memory and spatial cognition in adult survivors of childhood trauma. Study 1 compared the performance of 23 individuals who had experienced childhood abuse (the Trauma group) to 38 matched controls with no such experience (the Control group) on the four visual-spatial memory tasks of the Cambridge Neuropsychological Test Automated Battery (CANTAB). Results suggested that participants in the Trauma group showed poorer performance on two of the more complex tasks, which tapped both hippocampal and prefrontal cortex functioning, compared to the controls. One interpretation of this finding is that these between-group differences reflect the dysfunction of a network involved in visual-spatial memory in individuals who have experienced childhood trauma. Study 2 used functional magnetic resonance imaging (fMRI) to investigate whether any marked differences in neural activation would be evident between individuals with a history of childhood trauma (n = 7) and matched controls with no such history (n = 14) during spatial navigation tasks. Functional images were gathered while participants completed two spatial navigation tasks: the Computer-Generated Arena (CG Arena), a smallscale spatial navigation task, and the Virtual City, a large-scale spatial navigation task based on an environment created by Maguire et al. (1998). Although no significant behavioural differences were evident during the completion of these tasks, the fMRI data did show marked differences in activation. These results of the CG Arena, in particular, showed lower activation in PFC areas, including the anterior cingulate cortex, during wayfinding tasks. Taken together, the results of these two studies suggest that (a) subtly impaired neural functioning is evident in individuals with a history of childhood trauma, and (b) this impairment may lead to difficulties in successfully completing complex visual-spatial memory and spatial navigation tasks.
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Includes abstract.
Includes bibliographical references (leaves 77-93).
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Dey, M. 2009. The effect of early adversity on adult spatial cognition : a functional magnetic resonance imaging study. University of Cape Town.