Cognitive and anatomical correlates of neglect for peripersonal and extrapersonal space
Thesis or dissertation
- © 2008 Lina Aimola. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.
Spatial neglect is a neurological disorder where patients typically fail to orient or respond to events on their left side. Moreover, recent studies suggest that the severity of neglect may depend specifically on whether stimuli are presented within or beyond arm's reach. However, the evidence for such a general functional dissociation between near and far space processing in the brain remains conflicting: The majority of research has been focussed on line bisection errors which reflect only one small aspect of neglect behaviour. In addition, some behavioural findings suggest a functional dissociation only if a motor response is required. Finally, to date, the critical areas involved in distance related space processing have not been identified.
Thus, it remains not only unclear whether neglect in near and far space is a task- and response independent phenomenon but also which damaged brain areas impair distance related space processing. In order to answer these questions the present study compared line bisection and visual search performance and its anatomical correlates in near and far space by using a combined single case- and group study approach.
The results showed that neglect restricted to near or far space can vary not only depending on the type of task but also on the type of response required. Visual search tasks were particularly sensitive in detecting the dissociation between those two space sectors. Anatomically, neglect for near space was mainly associated with occipito-parietal lesions and medio-temporal structures, including the posterior cingulate. Neglect for far space was found to result from focal damage of medial, ventro-temporal structures and the prefrontal cortex. In conclusion, neglect for near and far space does not seem to result from a general impairment in distance related processing but from a combination of factors related to specific task demands as well as the location and extent of the brain damage.
- Department of Psychology, The University of Hull
- Schindler, Igor; Venneri, Annalena
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