Bachman Peter, Kim Junghoon, Yee Cindy M, Therman Sebastian, Manninen Marko, Lönnqvist Jouko, Kaprio Jaakko, Huttunen Matti O, Näätänen Risto, Cannon Tyrone D
Department of Psychology, University of California, Los Angeles, Los Angeles, CA 90095-1563, United States.
Psychiatry Res. 2009 Nov 30;174(2):97-104. doi: 10.1016/j.pscychresns.2009.04.010. Epub 2009 Oct 23.
It has been proposed that patients with schizophrenia and some of their relatives suffer from reduced neurocognitive efficiency, increasing their sensitivity to experimental task demands. The present study evaluated such a possibility during performance of a working memory task by schizophrenia patients and their co-twins along with a healthy control sample. Electrophysiological data were obtained from sets of nine twin pairs (monozygotic and dizygotic pairs collapsed) discordant for a diagnosis of schizophrenia and from nine matched healthy control twin pairs, during administration of a variable-load spatial working memory task. Event-related potentials (ERPs) were measured immediately after memory set onset and during a delay period. For correctly performed trials, slow-wave ERP activity measured during the late stimulus encoding and delay periods exhibited a significant Diagnostic Group-by-Memory Load interaction, with schizophrenia patients showing a differentially strong load effect. Patients' co-twins displayed an intermediate level of load sensitivity while healthy controls showed no significant load effect. These results support an inefficiency model of neurocognitive dysfunction in schizophrenia, a pattern that appears to be related to the pathogenesis and inheritance of the disorder. Furthermore, this inefficiency appeared during the late stimulus encoding stage of working memory functioning, possibly reflecting disruptions in stimulus representation consolidation.
有人提出，精神分裂症患者及其一些亲属存在神经认知效率降低的情况，这增加了他们对实验任务要求的敏感性。本研究在精神分裂症患者及其同卵双胞胎执行工作记忆任务以及与健康对照样本对比时，评估了这种可能性。在执行可变负荷空间工作记忆任务期间，从9对诊断为精神分裂症的不一致双胞胎（单卵双胞胎和双卵双胞胎合并）以及9对匹配的健康对照双胞胎中获取了电生理数据。在记忆组开始后以及延迟期立即测量事件相关电位（ERP）。对于正确完成的试验，在刺激编码后期和延迟期测量的慢波ERP活动表现出显著的诊断组与记忆负荷交互作用，精神分裂症患者表现出差异显著的负荷效应。患者的同卵双胞胎表现出中等水平的负荷敏感性，而健康对照者则未表现出显著的负荷效应。这些结果支持了精神分裂症神经认知功能障碍的低效率模型，这种模式似乎与该疾病的发病机制和遗传有关。此外，这种低效率出现在工作记忆功能的刺激编码后期阶段，可能反映了刺激表征巩固过程中的破坏。
