Department of Psychiatry, Imaging Research Center, University of California Davis, 4701 X Street, Sacramento, CA 95817, USA.
Neuroimage. 2012 Jan 16;59(2):1719-26. doi: 10.1016/j.neuroimage.2011.08.055. Epub 2011 Aug 31.
Successful long-term memory (LTM) depends upon effective control of information in working memory (WM), and there is evidence that both WM and LTM are impaired by schizophrenia. This study tests the hypothesis that LTM deficits in schizophrenia may result from impaired control of relational processing in WM due to dorsolateral prefrontal cortex (DLPFC) dysfunction. fMRI was performed on 19 healthy controls and 20 patients with schizophrenia during WM tasks emphasizing relational (reorder trials) versus item-specific (rehearse trials) processing. WM activity was also examined with respect to LTM recognition on a task administered outside the scanner. Receiver operator characteristic analysis assessed familiarity and recollection components of LTM. Patients showed a disproportionate familiarity deficit for reorder versus rehearse trials against a background of generalized LTM impairments. Relational processing during WM led to DLPFC activation in both groups. However, this activation was less focal in patients than in controls, and patients with more severe negative symptoms showed less of a DLPFC increase. fMRI analysis of subsequent recognition performance revealed a group by condition interaction. High LTM for reorder versus rehearse trials was associated with bilateral DLPFC activation in controls, but not in patients who activated the left middle temporal and inferior occipital gyrus. Results indicate that although patients can activate the DLPFC on a structured relational WM task, this activation is less focal and does not translate to high retrieval success, suggesting a disruption in the interaction between WM and LTM processes in schizophrenia.
成功的长期记忆 (LTM) 取决于工作记忆 (WM) 中信息的有效控制，有证据表明 WM 和 LTM 都受到精神分裂症的损害。本研究检验了这样一个假设，即精神分裂症患者的 LTM 缺陷可能是由于 WM 中关系处理的控制受损导致的，而 WM 中关系处理的控制受损是由于背外侧前额叶皮层 (DLPFC) 功能障碍。在进行 WM 任务时，对 19 名健康对照者和 20 名精神分裂症患者进行了 fMRI 检查，这些任务强调了关系 (重新排序试验) 与项目特定 (重复试验) 处理。还根据在扫描仪外进行的任务检查了 WM 活动与 LTM 识别的关系。接收器操作特性分析评估了 LTM 的熟悉度和回忆成分。与一般 LTM 损伤相比，患者对重新排序试验的熟悉度缺陷不成比例，而对重复试验的熟悉度缺陷不成比例。在 WM 期间进行的关系处理导致两组 DLPFC 激活。然而，与对照组相比，患者的激活不那么集中，且具有更严重阴性症状的患者 DLPFC 增加较少。随后的识别性能 fMRI 分析显示出组与条件的相互作用。与控制组相比，在控制组中，重新排序与重复试验的高 LTM 与双侧 DLPFC 激活相关，但在患者中，这种激活与左侧颞中回和下枕叶激活无关。结果表明，尽管患者可以在结构关系 WM 任务上激活 DLPFC，但这种激活不那么集中，并且不能转化为高检索成功，这表明在精神分裂症中 WM 和 LTM 过程之间的相互作用受到干扰。
