Abstract
Recently, Emrich, Burianová, and Ferber (2011) reported that high visual working memory (VWM) load can induce a neglect-like disadvantage in object recognition, confined to the viewer’s left hemifield. The authors suggested that inhibition of the right temporoparietal junction (TPJ) which results from high VWM load causes interference with selecting objects from the left side of space. This explanation fits well with the role of TPJ lesions in causing visual neglect. But is the nature of this transient, load-induced perceptual neglect similar to the neglect behaviour observed in patient populations? One way to address this question is to test the sensitivity of this transient neglect to manipulations of spatial reference frames. Neglect patients show deficits not only in retino-centric reference frames, but also in stimulus-centered reference frames. To determine if load-induced transient neglect is also sensitive to stimulus-centred reference frames, we used a change-detection task containing conceptual cues (e.g., ‘left’, ‘above’) to probe a memory item on each trial. Critically, subjects were told to interpret the cues within a particular reference frame (rotated 0°, 90°, or 180° from the retino-centric frame) fixed throughout an entire block. Performance on the change-detection task served as a manipulation check to monitor subjects' ability to maintain the stimulus-based reference frame. Object recognition stimuli were presented on 30% of trials, bilaterally, allowing a comparison between both the retino-centric and stimulus-centered left and right. Results suggest that load-induced transient neglect is only a function of the retino-centric reference frame and does not depend on higher-order reference frames. Importantly, these results suggest that load-induced perceptual neglect does not capture the full extent of visual neglect symptoms and is primarily due to inhibited visual encoding.
Meeting abstract presented at VSS 2012