Functional magnetic resonance imaging brain mapping in psychiatry: Methodological issues illustrated in a study of working memory in schizophrenia
Functional magnetic resonance imaging brain mapping in psychiatry: Methodological issues illustrated in a study of working memory in schizophrenia
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DOI：
10.1016/s0893-133x(97)00096-1
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发表时间：
1998-03-01
影响因子：
7.6
通讯作者：
Weinberger, DR
中科院分区：
文献类型：
--
作者：
Callicott, JH;Ramsey, NF;Weinberger, DR
功能磁共振成像（fMRI）是精神神经影像学的一个潜在的范式转变。这项技术提供的是个体而不是群体平均的功能性神经影像学数据，但微妙的方法学混淆代表了精神病学研究的独特挑战。作为功能磁共振成像的独特潜力和问题的一个范例，我们提出了一项研究，10名住院精神分裂症患者和10名对照执行一个新的“n回”工作记忆（WM）任务。我们强调两个关键的设计步骤：（1）使用内部激活标准（即，生理控制区域）以解决激活有效性，以及（2）信号稳定性的评估以控制由组间不相等的信号方差引起的“激活”伪影。在最初的分析中，除了一名患者外，所有患者在工作记忆任务中都未能激活背外侧前额叶皮层（DLPFC）。然而，一些患者（和一个对照）也倾向于显示稀疏的控制区激活，尽管正常的运动性能，结果引起怀疑的有效性的初步分析和不平等的主题运动的关注。然后，对受试者进行信号方差（体素稳定性）的匹配，产生六个患者和六个对照的子集。在该比较中，内部活化标准品（即，运动激活）在两组中相似，6名患者中有5名，包括2名未接受过抗精神病药物治疗的患者，未能激活DLPFC。此外，还观察到顶叶皮质过度激活的趋势。这些结果说明了功能磁共振成像的一些前景和缺陷。虽然功能性磁共振成像生成的是个体的脑图，但为了避免与运动等伪影相关的虚假或不可靠的结果，有必要对数据进行专门的调查，这些伪影在精神病患者中可能很常见。出版社：Elsevier Science Inc.
Functional magnetic resonance imaging (fMRI) is a potential paradigm shift in psychiatric neuroimaging. The technique provides individual, rather than group-averaged, functional neuroimaging data, but subtle methodological confounds represent unique challenges for psychiatric research. As an exemplar of the unique potential and problems of fMRI, we present a study of 10 inpatients with schizophrenia and 10 controls performing a novel "n back" working memory (WM) task. We emphasize two key design steps: (1) the use of an internal activation standard (i.e., a physiological control region) to address activation validity, and (2) the assessment of signal stability to control for "activation" artifacts arising from unequal signal variance across groups. In the initial analysis, all but one of the patients failed to activate dorsolateral prefrontal cortex (DLPFC) during the working memory task. However, some patients (and one control) also tended to show sparse control region activation in spite of normal motor performance, a result that raises doubts about the validity of the initial analysis and concerns about unequal subject motion. subjects were then matched for signal variance (voxel stability), producing a subset of six patients and six controls. In this comparison, the internal activation standard (i.e., motor activation) was similar in both groups, and five of six patients, including two whom were neuroleptic-naive, failed to activate DLPFC. In addition, a tendency for overactivation of parietal cortex was seen. These results illustrate some of the promise and pitfalls of fMRI. Although fMRI generates individual brain maps, a specialized survey of the data is necessary to avoid spurious or unreliable findings, related to artifacts such as motion, which are likely to be frequent in psychiatric patients. Published by Elsevier Science Inc.