Price C J, Friston K J
Wellcome Department of Cognitive Neurology, Institute of Neurology, London, United Kingdom.
Neuroimage. 1997 May;5(4 Pt 1):261-70. doi: 10.1006/nimg.1997.0269.
This paper introduces the concepts and procedures of "cognitive conjunction," a new approach to designing and analyzing cognitive activation experiments. Cognitive conjunction compliments categorical approaches such as cognitive subtraction and requires a specific form of statistical inference that involves the conjunction of several hypotheses. While cognitive subtraction studies are designed such that a pair of tasks differ only by the processing component(s) of interest, cognitive conjunction studies are designed such that two or more distinct task pairs each share a common processing difference. The neural correlates of the process of interest are then associated with the common areas of activation for each task pair. There are two main advantages of cognitive conjunction relative to cognitive subtraction. The first is that it provides a greater latitude for selecting baseline tasks because it is not necessary to control for all but the component of interest. The only constraint on selecting the baseline is that the component of interest is the only process that differs in each task pair. The second advantage is that cognitive conjunction does not depend on "pure insertion"--the assumption that the addition of an extra processing component in the activation task has no effect on the implementation of processes that are also engaged by the baseline task. The differences between the design and the statistical analysis of experiments based on cognitive subtraction, cognitive conjunction, and factorial designs are illustrated with a study of phonological retrieval. Cognitive conjunction analysis indicates that irrespective of whether subjects name words, objects, letters, or colors, there is activation of the left posterior basal temporal lobe, the left frontal operculum, the left thalamus, and the midline cerebellum.
本文介绍了“认知联合”的概念和程序，这是一种设计和分析认知激活实验的新方法。认知联合是对诸如认知减法等分类方法的补充，并且需要一种特定形式的统计推断，这种推断涉及几个假设的联合。认知减法研究的设计使得一对任务仅在感兴趣的处理成分上有所不同，而认知联合研究的设计则使得两个或更多不同的任务对各自共享一个共同的处理差异。然后，将感兴趣的过程的神经关联与每个任务对的共同激活区域联系起来。相对于认知减法，认知联合有两个主要优点。第一个优点是它在选择基线任务方面提供了更大的自由度，因为不必控制除感兴趣的成分之外的所有因素。选择基线的唯一限制是感兴趣的成分是每个任务对中唯一不同的过程。第二个优点是认知联合不依赖于“纯插入”——即激活任务中额外处理成分的添加对基线任务所涉及的过程的执行没有影响这一假设。通过一项语音检索研究说明了基于认知减法、认知联合和析因设计的实验在设计和统计分析上的差异。认知联合分析表明，无论受试者是命名单词、物体、字母还是颜色，左后基底颞叶、左额下回、左丘脑和中线小脑都会被激活。
