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Sabira Mannan

Publications and source records attributed to Sabira Mannan.

2 recordsLinked to original sources
PubMed2002

Visual object memory and memory-guided saccades rely on shared mental representations.

We investigated the organisation of working memory processes by examining how a secondary memory task interferes with the accuracy of memory-guided saccades. A target was flashed at a random location, followed by a Kanji character. Subjects had to remember the location of the target and the Kanji character, and then they had to make a saccade towards the remembered target location. A second Kanji character was displayed and the subject had to decide if it was same or different. The performance of seven non-Kanji reader's were compared with six fluent Kanji readers in the task. Memorisation of Kanji characters was found to interfere with the accuracy of memory-guided saccades made by non-Kanji, but not by Kanji readers. These findings directly contradict accounts of working memory function which propose that spatial and visual object memory are functionally discrete.

Adult↗
PubMedDate not supplied

Impaired spatial working memory: one component of the visual neglect syndrome?

Both impaired spatial working memory (SWM) and unilateral neglect may follow damage to the right parietal lobe. We propose that impaired SWM can exacerbate visual neglect, due to failures in remembering locations that have already been searched. When combined with an attentional bias to the ipsilesional right side, such a SWM impairment should induce recursive search of ipsilesional locations. Here we studied a left neglect patient with a right temporoparietal haemorrhage. On a nonlateralised, purely vertical SWM task, he was impaired in retaining spatial locations. In a visual search task, his eye position was monitored while his spatial memory was probed. He recursively searched through right stimuli, re-fixating previously inspected items, and critically treated them as if they were new discoveries, consistent with the SWM deficit. When his recovery was tracked over several months, his SWM deficit and left neglect showed concurrent improvements. We argue that impaired SWM may be one important component of the visual neglect syndrome.

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