University of Maryland School of Medicine, Maryland Psychiatric Research Center, P.O. box 21247, Baltimore, MD 21228, USA.
Schizophr Res. 2012 Jan;134(1):70-5. doi: 10.1016/j.schres.2011.10.008. Epub 2011 Nov 12.
People with schizophrenia (PSZ) exhibit signs of reduced working memory (WM) capacity. However, this may reflect an impairment in managing its content, e.g. preventing irrelevant information from taking up available storage space, rather than a true capacity reduction. We tested the ability to eliminate and update WM content in 38 PSZ and 30 healthy control subjects (HCS). Images of real-world objects were presented consecutively, and a tone cued the item most likely to be tested for memory. On half the trials, randomly intermixed, a second tone occurred. Participants were informed that the item cued by the second tone was now the most likely to be tested, and the item cued by the first tone now the least likely, providing incentive to eliminate the first cued item from WM. Both HCS and PSZ displayed a robust performance advantage for cued items. Unexpectedly, PSZ more efficiently removed the no-longer-essential item from WM than HCS. The magnitude of the WM clearance of this first cued item correlated with memory performance for the newly prioritized second cued item in PSZ, indicating that it was adaptive. However, WM clearance was not associated with WM capacity, ruling out the need to budget limited resources as an explanation for greater clearance in PSZ. A robust correlation between WM clearance and poverty of speech in PSZ instead suggests that the propensity to rapidly clear non-essential information and minimize the number of items in WM may be the reflection of a negative symptom trait. This finding may reflect a more general tendency of PSZ to focus processing more narrowly than HCS.
精神分裂症患者（PSZ）表现出工作记忆（WM）容量减少的迹象。然而，这可能反映了对其内容的管理能力受损，例如防止不相关信息占用可用存储空间，而不是真正的容量减少。我们测试了 38 名 PSZ 和 30 名健康对照组（HCS）消除和更新 WM 内容的能力。真实物体的图像连续呈现，并且一个音调提示最有可能用于记忆测试的项目。在一半的试验中，随机混合，会出现第二个音调。参与者被告知第二个音调提示的项目现在最有可能被测试，而第一个音调提示的项目现在最不可能被测试，这为从 WM 中消除第一个提示的项目提供了动力。HCS 和 PSZ 都显示出对提示项目的强大表现优势。出乎意料的是，PSZ 比 HCS 更有效地从 WM 中删除不再必要的项目。第一个提示项目的 WM 清除量与 PSZ 中第二个新优先提示项目的记忆表现相关，表明这是适应性的。然而，WM 清除量与 WM 容量无关，排除了需要为 PSZ 中的更大清除量分配有限资源的必要性。PSZ 中 WM 清除量与言语贫乏之间存在强大的相关性表明，迅速清除非必要信息并将 WM 中的项目数量最小化的倾向可能是一种消极症状特征的反映。这一发现可能反映了 PSZ 比 HCS 更倾向于更狭窄地集中处理信息的更普遍趋势。
