Tek Cenk, Gold James, Blaxton Teresa, Wilk Christopher, McMahon Robert P, Buchanan Robert W
Maryland Psychiatric Research Center, PO Box 21246, Baltimore, MD 21228, USA.
Arch Gen Psychiatry. 2002 Feb;59(2):146-53. doi: 10.1001/archpsyc.59.2.146.
Impairments in working memory have been proposed to underlie a broad range of cognitive deficits seen in schizophrenia. Visual working memory impairments are frequently reported in schizophrenia. Investigations of visual working memory generally assume intact visual information processing, despite evidence of visual perceptual impairments in schizophrenia. In this study, we evaluated the integrity of the perceptual system for object and spatial visual information and the relevant working memory system, after adjusting for individual perceptual performance differences.
Thirty patients with schizophrenia and 20 healthy control subjects underwent testing using a task of perceptual discrimination of spatial and object visual stimuli. For testing visual working memory, a delay was introduced to the perceptual discrimination task. A thresholding procedure was used so that each subject adequately perceived the information during the working memory test.
Subjects with schizophrenia exhibited impaired performance relative to controls for object and spatial visual perceptual discrimination. The extent of impairment was greater for the object than for the spatial test. After controlling for perceptual impairments, the subjects with schizophrenia exhibited impaired performance relative to controls for the spatial working memory test but not the object working memory test.
Findings implicate dysfunction of posterior brain areas that mediate visual perceptual processing and the prefrontal areas involved in the active maintenance of information during delay intervals. However, the systems that govern object and spatial visual perception and working memory appear to be affected differentially by schizophrenia.
工作记忆受损被认为是精神分裂症中广泛存在的认知缺陷的潜在原因。精神分裂症患者经常出现视觉工作记忆受损的情况。尽管有证据表明精神分裂症患者存在视觉感知障碍，但视觉工作记忆的研究通常假定视觉信息处理是完整的。在本研究中，我们在调整个体感知表现差异后，评估了物体和空间视觉信息的感知系统以及相关工作记忆系统的完整性。
30名精神分裂症患者和20名健康对照者使用空间和物体视觉刺激的感知辨别任务进行测试。为了测试视觉工作记忆，在感知辨别任务中引入了延迟。使用了一种阈值化程序，以便每个受试者在工作记忆测试期间能够充分感知信息。
与对照组相比，精神分裂症患者在物体和空间视觉感知辨别方面表现受损。物体测试的受损程度大于空间测试。在控制了感知障碍后，与对照组相比，精神分裂症患者在空间工作记忆测试中表现受损，但在物体工作记忆测试中未受损。
研究结果表明，介导视觉感知处理的后脑区域以及在延迟间隔期间参与信息主动维持的前额叶区域功能失调。然而，精神分裂症似乎对控制物体和空间视觉感知及工作记忆的系统产生不同程度的影响。
