Examining encoding imprecision in spatial working memory in schizophrenia
Examining encoding imprecision in spatial working memory in schizophrenia
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DOI：
10.1016/j.schres.2007.08.005
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发表时间：
2008-03-01
影响因子：
4.5
通讯作者：
Jablensky, Assen
中科院分区：
文献类型：
--
作者：
Badcock, Johanna C.;Badcock, David R.;Jablensky, Assen
视觉空间工作记忆不是一个单一的速写板，而是由目标距离和方向的独立维度以及至少两个细节水平（细粒度和类别水平）组成。本研究的目的是使用修改的延迟反应任务来检查精神分裂症患者编码的这些多个方面。方法：42名精神分裂症患者和48名健康对照者从固定的开始位置尽可能准确地指向呈现在触摸屏上的目标刺激的视觉位置。一个自适应的阶梯程序被用来等同于每个人的刺激持续时间。在0秒（立即）或4秒（未填充）延迟后检查编码精度和距离（mm）和方向（度）信息的保持。分析利用绝对（无符号）和签署data.Results：结果表明，检测目标所需的平均持续时间显着长于患者比对照组。当刺激持续时间相等时，（a）在0秒延迟时，两组之间的距离和方向反应的绝对准确性没有显著差异，但在4秒延迟时，精神分裂症患者的绝对准确性显著降低，（B）在刺激角度大于90度时，4秒延迟时的符号方向错误在两组之间存在显著差异。研究结果挑战了以前的建议，在精神分裂症的空间信息的细粒度编码的赤字，但确认难以保持工作记忆中的方向和距离的细节。精神分裂症患者空间记忆的不精确性也会导致类别水平（先前）表征的更大偏差，尤其是在左半空间。皇冠版权所有（C）2007年出版的爱思唯尔B.V.保留所有权利。
Background Visuospatial working memory is not a unitary sketch pad but comprises independent dimensions of target distance and direction and at least two levels of detail (fine-grained and category level). The aim of this study was to examine these multiple aspects of encoding in patients with schizophrenia using a modified delayed response task.Method: 42 patients with schizophrenia and 48 healthy controls pointed, as accurately as possible from a fixed starting position, to the visual location of target stimuli presented to a touch-sensitive screen. An adaptive staircase procedure was used to equate stimulus duration for each individual. Encoding accuracy and maintenance of distance (mm) and direction (degrees) information was examined following a 0-second (immediate) or 4-second (unfilled) delay. Analyses utilized both absolute (unsigned) and signed data.Results: The results showed that the average duration required to detect a target was significantly longer in patients than controls. When stimulus duration was equated, (a) the absolute accuracy of distance and direction responses was not significantly different between groups at 0-second delay but was significantly reduced at 4-second delay in patients with schizophrenia, and (b) signed direction errors at 4-second delay were significantly different between groups at stimulus angles greater than 90 degrees.Conclusions: The findings challenge previous suggestions of deficits in fine-grained encoding of spatial information in schizophrenia but confirm a difficulty maintaining both direction and distance details in working memory. Imprecision in spatial memory in schizophrenia also introduced greater bias from category level (prior) representations, especially in left hemi-space. Crown Copyright (C) 2007 Published by Elsevier B.V. All rights reserved.