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首页> 外文学位 >Sources of variability in neuroimaging findings of frontal lobe dysfunction in schizophrenia: Single subject contributions to group effects.
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Sources of variability in neuroimaging findings of frontal lobe dysfunction in schizophrenia: Single subject contributions to group effects.

机译：精神分裂症的额叶功能障碍的神经影像学发现的变异性来源：单个受试者对小组效应的贡献。

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摘要

Prefrontal hypofunction is the most frequently reported finding in functional neuroimaging studies of schizophrenia. The meaning of this so-called ‘hypofrontality’ has remained unclear, being typically interpreted as impaired recruitment of prefrontal cortical neurons. Alternatively, however, between-group differences in variability along several parameters could produce such findings. A major impediment to more precise understanding of prefrontal hypofunction is that, until recently, functional activation maps could only be assessed by using group average statistics. In such group-average data the variance may be derived from a number of neurobiologically meaningful sources. These include variability across individuals in intensity of activation, average activity within a contiguous cluster of voxels, and variability in the neuroanatomical locale of the evoked neural activation. For example, inter-individual “scatter” of functional locales could result in fewer commonly activated voxels, with resultant underestimation of cortical response. These sources of variability may have a major impact on group signals. We recently developed methods for comparing patients to controls which, by assessing the activation pattern for each individual subject, separately evaluate multiple sources of variance, including peak activation intensity, spatial extent of an activated region, and variability in location of functional neuroanatomical signal. We piloted these methods in a study of the motor cortex, an area previously reported to be hypofunctional in schizophrenia and found that although group-average level analyses suggested patients to be hypofunctional, this finding was not supported by single-subject analyses. The group level finding was produced primarily by increased variability of activation locale in the patients.; These methods were applied to a study of patients and control subjects who performed a working memory test during PET scanning. Group-level analysis revealed dorsolateral prefrontal cortex (DLPFC) hypofunction in the patients. In contrast to the pilot study, single subject analyses in these subjects revealed that DLPFC activations of patients were significantly smaller in volume and with significantly lower magnitude of activation. However, the locales of patients activations were more variable than controls activations. This analysis demonstrates that patients have deficits in multiple parameters of the neuroimaging signal and confirms that prefrontal hypofunction in patients with schizophrenia represents true pathophysiology.
机译：前额叶功能减退是精神分裂症功能性神经影像学研究中最常报告的发现。这种所谓的“低前锋性”的含义仍不清楚，通常被解释为前额叶皮层神经元的募集受损。然而，替代地，沿着几个参数的变异性的组间差异可以产生这样的发现。对前额叶功能减退的更精确理解的主要障碍是，直到最近，功能激活图只能通过使用组平均统计来评估。在这样的组平均数据中，方差可以从许多神经生物学上有意义的来源中得出。这些包括激活强度在个体之间的变异性，连续的体素簇内的平均活动性以及诱发的神经激活的神经解剖学部位的变异性。例如，功能区域之间的个体“分散”可能会导致较少的通常被激活的体素，从而导致皮质反应的低估。这些可变性来源可能会对群组信号产生重大影响。我们最近开发了将患者与对照进行比较的方法，该方法通过评估每个个体受试者的激活模式，分别评估多种变异来源，包括峰值激活强度，激活区域的空间范围以及功能性神经解剖信号的位置变异性。我们在运动皮层的研究中试用了这些方法，运动皮层以前据报道在精神分裂症中功能低下，并且发现，尽管组平均水平分析表明患者功能低下，但单项分析不支持这一发现。组水平的发现主要是由于患者激活区域的变异性增加所致。这些方法用于研究在PET扫描期间执行工作记忆测试的患者和对照组。组水平分析显示患者的背外侧前额叶皮层（DLPFC）功能低下。与该先导研究相反，这些受试者中的单个受试者分析表明，患者的DLPFC激活的体积明显较小，且激活幅度明显较低。但是，患者激活的区域比对照组的激活更多。该分析表明患者在神经影像信号的多个参数方面存在缺陷，并证实精神分裂症患者的前额叶功能减退代表了真正的病理生理学。

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  • 作者

    Holt, John Leonard.;

  • 作者单位

    Rutgers The State University of New Jersey - New Brunswick.;

  • 授予单位 Rutgers The State University of New Jersey - New Brunswick.;
  • 学科 Biology Neuroscience.; Engineering Biomedical.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 126 p.
  • 总页数 126
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 神经科学;生物医学工程;
  • 关键词

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