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Brandon Vasquez, Jonathan Carriere, James Danckert; Direction specific impairments of spatial working memory as a consequence of saccadic remapping. Journal of Vision 2007;7(9):669. doi: 10.1167/7.9.669.
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© ARVO (1962-2015); The Authors (2016-present)
One of the most common impairments resulting from right parietal stroke is a disorder called visuospatial neglect, in which patients behave as if half their world has ceased to exist. Current theoretical attempts to explain neglect have suggested that, in addition to attentional biases, these patients also demonstrate impairments of spatial working memory and/or spatial remapping. These two mechanisms are closely related in that they are critically important for maintaining and updating spatial representations in our environment. We examined the influence of saccadic remapping processes on spatial working memory in a group of healthy individuals. Participants first had to determine the presence or absence of a target (a circle with a small segment removed) presented amongst distractor stimuli (full circles). On trials in which a target was detected, a probe stimulus then appeared, following a brief delay (1 sec). Participants had to indicate whether or not the probe occupied the location of the previously detected target stimulus. Critically, we manipulated fixation during the delay condition such that fixation could remain static or could move to the left, right, up or down. These four shift conditions required the participant to remap the target display in order to make accurate decisions concerning the spatial location of the probe. Performance for judging the spatial location of the probe was best when central fixation was maintained. Interestingly, decrements in SWM (i.e. accurately matching the target location with the probe) were only observed when saccadic remapping was executed into right or lower visual space. This suggests that saccadic remapping processes interact with SWM processes in specific ways that may be related to both hemispheric biases in attention for changes induced by lateral remapping, and differences in personal versus extrapersonal space for changes induced by vertical remapping.
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