Activation: will hot spots get the hot field in hot water?
Activation: will hot spots get the hot field in hot water?
复制标题
激活：热点会在热水中获得热场吗？
DOI：
10.1016/j.bandl.2007.02.001
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发表时间：
2007
影响因子：
2.5
通讯作者：
Sidtis,JohnJ
中科院分区：
文献类型：
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作者：
Sidtis,JohnJ
“一闪一闪，小星星，我多么想知道你是什么”（泰勒，1813）。在天空或其他地方，亮点长期以来一直吸引着人们的想象力，往往导致神奇的思考和诗意的诗句。在功能成像领域中，代表性方案通常将大脑中具有最高信号值的区域在一个或多个减法或其他对比之后描绘为具有颜色方案中最亮值的热点。这些点通常被认为是大脑的激活区域。对许多人来说，光点越亮，激活就越大，由此推断，对所研究的行为的功能意义就越大。在早期的成像世界中，星星凝视通常包括“峰值拾取”或识别最亮或最热的点。随着对功能图像解释的成熟，许多研究者已经从“峰值拾取”转向大脑网络的概念，但这并不总是与早期的概念有很大的不同，因为大脑网络通常被简单地描述为热点的星座。在这期关于激活的特刊中，我们将讨论这个概念的一些问题，因为它们与建立大脑-行为关系的问题有关。在第一篇论文中，Sidtis概述了激活方法的主要假设：实验任务将导致血流或血液动力学反应的显著增加，并且实验和对照条件之间的对比将识别与实验任务神经生理学相关的信号。由于激活方法依赖于对比过程，因此进一步假设可以通过对比成像条件来隔离心理过程，由对比生成的数据具有有用的测量属性，并且可以独立于由对比消除的区域来解释由对比识别的区域的功能。Sidtis指出，目前的激活概念导致了对运动语言控制的大脑组织的描述，这与损伤研究的结果不一致。他表明，基于性能的分析，不依赖于对比度，产生的功能成像结果与病变的研究是一致的。Sidtis认为，对比度方法是有缺陷的，并且单独的图像数据，无论它们受到的对比度如何，似乎都不足以映射功能性大脑组织。
“Twinkle, twinkle, little star, how I wonder what you are”(Taylor, 1813). In the sky or elsewhere, bright spots have long captured the imagination, often leading to magical thinking and poetic verse. In the universe of functional imaging, representational schemes have typically depicted areas in the brain with the highest signal values following one or more subtractions or other contrasts as hot spots with the brightest values in a color scheme. Such spots are commonly regarded as activated areas of the brain. To many, the brighter the spot, the greater the activation, and by inference, the greater the functional significance to the behavior under study. Star gazing in the early imaging world often consisted of “peak picking” or identifying the brightest or hottest spots. As the interpretation of functional images has matured, many investigators have moved away from “peak picking” toward notions of brain networks, but this is not always a great departure from earlier conceptualizations because brain networks are often characterized simply as constellations of hot spots. In this special issue on activation, a number of problems with this concept will be discussed as they relate to the problem of establishing brain–behavior relationships.In the first paper, Sidtis outlines the major assumptions of the activation approach: an experimental task will result in significant increases in blood flow or hemodynamic response, and contrasts between experimental and control conditions will identify signals that are neurophysiologically relevant to the experimental task. Because the activation approach relies on a contrast procedure, it is further assumed that mental processes can be isolated by contrasting imaging conditions, data generated by contrasts have useful measurement properties, and the function of areas identified by a contrast can be interpreted independent of areas eliminated by the contrast. Sidtis points out that the current notion of activation leads to a characterization of brain organization for motor speech control that is at odds with the results of lesion studies. He shows that a performance-based analysis, which does not rely on contrasts, yields functional imaging results that are consistent with lesion studies. Sidtis argues that the contrast approach is flawed and that image data alone, regardless of the contrasts to which they are subjected, do not appear sufficient for mapping functional brain organization.