Transient and sustained BOLD signal time courses affect the detection of emotion-related brain activation in fMRI
Transient and sustained BOLD signal time courses affect the detection of emotion-related brain activation in fMRI
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DOI：
10.1016/j.neuroimage.2014.08.054
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发表时间：
2014-12
期刊：
影响因子：
5.7
通讯作者：
C. Paret;R. Kluetsch;M. Ruf;T. Demirakca;R. Kalisch;C. Schmahl;G. Ende
中科院分区：
文献类型：
--
作者：
C. Paret;R. Kluetsch;M. Ruf;T. Demirakca;R. Kalisch;C. Schmahl;G. Ende
人们付出了巨大的努力来揭示处理和调节情绪的功能神经解剖学，从而对涉及的边缘、副边缘和前额叶区域进行了很好的描述。应用功能磁共振成像（fMRI）的研究通常使用具有情感内容的刺激块呈现，并传统地将大脑激活模型作为刺激或任务持续时间的函数。然而，越来越多的证据表明，区域大脑反应可能并不总是转化为任务持续时间，而是显示与刺激发作相关的短暂时间过程。我们假设使用传统的功能磁共振成像分析方法无法在块设计中检测到显示瞬态反应的大脑区域。同时，如果在一个区块中使用更短的刺激时间或更强的刺激，则常规分析检测到这些区域的概率可能会增加。在被试fMRI研究中，我们向20名健康被试提供了厌恶图片，并研究了实验设计（事件相关设计和块组设计）对检测情绪处理感兴趣的大脑边缘和副边缘区域激活的影响。除了在刺激呈现块期间持续激活的传统建模之外，我们在一般线性模型（GLM）中加入了第二个响应函数，适合于检测块开始时的瞬态时间过程。在传统的分析中，杏仁核、丘脑和导水管周围灰质等几个区域被激活，而与设计无关。然而，在事件相关分析中，我们发现前脑岛（AI）有积极的BOLD反应，但在分组设计分析中没有。GLM分析表明，这种差异可能是由传统的功能磁共振成像分析方法无法捕获的瞬态响应模式造成的。我们的研究结果表明，如果分析不考虑瞬态响应，那么具有像AI这样的瞬态响应剖面的区域可能会在块设计中被遗漏。这可能会使实证报告和荟萃分析的结论偏向于低估这些区域及其在情绪和情绪调节中的作用。讨论了不同时间过程下的认知过程。
A tremendous amount of effort has been dedicated to unravel the functional neuroanatomy of the processing and regulation of emotion, resulting in a well-described picture of limbic, para-limbic and prefrontal regions involved. Studies applying functional magnetic resonance imaging (fMRI) often use the block-wise presentation of stimuli with affective content, and conventionally model brain activation as a function of stimulus or task duration. However, there is increasing evidence that regional brain responses may not always translate to task duration and rather show stimulus onset-related transient time courses. We assume that brain regions showing transient responses cannot be detected in block designs using a conventional fMRI analysis approach. At the same time, the probability of detecting these regions with conventional analyses may be increased when shorter stimulus timing or a more intense stimulation during a block is used.In a within-subject fMRI study, we presented aversive pictures to 20 healthy subjects and investigated the effect of experimental design (i.e. event-related and block design) on the detection of brain activation in limbic and para-limbic regions of interest of emotion processing. In addition to conventional modeling of sustained activation during blocks of stimulus presentation, we included a second response function into the general linear model (GLM), suited to detect transient time courses at block onset. In the conventional analysis, several regions like the amygdala, thalamus and periaqueductal gray were activated irrespective of design. However, we found a positive BOLD response in the anterior insula (AI) in event-related but not in block-design analyses. GLM analyses suggest that this difference may result from a transient response pattern which cannot be captured by the conventional fMRI analysis approach. Our results indicate that regions with a transient response profile like the AI can be missed in block designs if analyses do not account for transient responses. This may bias conclusions from empirical reports and meta-analyses towards an underestimation of these regions and their role in emotion and emotion regulation. The cognitive processes underlying differential time courses are discussed.