Veterans Affairs Medical Center and University of Minnesota Medical School.
J Cogn Neurosci. 1997 Jul;9(4):419-32. doi: 10.1162/jocn.1997.9.4.419.
We studied the performance and cortical activation patterns during a mental rotation task (Shepard & Metzler, 1971) using functional magnetic resonance imaging (fMlU) at high field (4 Tesla). Twenty-four human subjects were imaged (fMRI group), whereas six additional subjects performed the task without being imaged (control group). All subjects were shown pairs of perspective drawings of 31, objects and asked to judge whether they were the same or mirror images. The measures of performance examined included (1) the percentage of errors, (2) the speed of performance, calculated as the inverse of the average response time, and (3) the rate of rotation for those object pairs correctly identified as "same." We found the following: (1) Subjects in the fMRI group performed well outside and inside the magnet, and, in the latter case, before and during data acquisition. Moreover, performance over time improved in the same manner as in the control group. These findings indicate that exposure to high magnetic fields does not impair performance in mental rotation. (2) Functional activation data were analyzed from 16 subjects of the fMRI goup. Several cortical areas were activated during task performance. The relations between the measures of performance above and the magnitude of activation of specific cortical areas were investigated by anatomically demarcating these areas of interest and calculating a normalized activation for each one of them. (3) We used the multivariate technique of hierarchical tree modeling to determine functional clustering among areas of interest and performance measures. Two main branches were distinguished: One comprised areas in the right hemisphere and the extrastriate and superior parietal lobules bilaterally, whereas the other comprised areas of the left hemisphere and the frontal pole bilaterally; all three performance measures above clustered with the former branch. Specifically, performance outcome ("percentage of errors") clustered with the parieto-occipital subcluster, whereas both the speed of performance and the rate of mental rotation clustered with the right precentral gyms. We conclude that the mental rotation paradigm used involves the cooperative interaction of functional groups of cortical areas of which some are probably more specifically associated with performance, whereas others may serve a more general function within the task constraints.
我们使用高磁场（4 特斯拉）功能磁共振成像（fMRI）研究了心理旋转任务（Shepard 和 Metzler，1971）中的表现和皮质激活模式。我们对 24 名人类受试者进行了成像（fMRI 组），而另外 6 名受试者则在没有成像的情况下完成了任务（对照组）。所有受试者都观看了 31 个物体的透视画对，并被要求判断它们是否相同或镜像。检查的表现衡量标准包括：（1）错误百分比；（2）表现速度，计算为平均反应时间的倒数；（3）正确识别为“相同”的物体对的旋转速度。我们发现：（1）在磁共振内外，fMRI 组的受试者表现良好，在后者情况下，在数据采集之前和期间表现良好。此外，表现随时间的推移以与对照组相同的方式提高。这些发现表明，暴露于高磁场不会损害心理旋转的表现。（2）从 fMRI 组的 16 名受试者中分析了功能激活数据。在任务执行过程中激活了几个皮质区域。通过解剖地标定这些感兴趣的区域并计算每个区域的归一化激活，研究了上述表现衡量标准与特定皮质区域激活幅度之间的关系。（3）我们使用层次树建模的多元技术来确定感兴趣区域和表现衡量标准之间的功能聚类。区分出两个主要分支：一个分支包括右半球和双侧的枕叶和顶叶上回的区域，另一个分支包括左半球和双侧的额极的区域；上述三个表现衡量标准都与前一分支聚类。具体来说，表现结果（“错误百分比”）与枕叶-顶叶子聚类聚类，而表现速度和心理旋转速度都与右中央前回聚类。我们的结论是，所使用的心理旋转范式涉及皮质区域的功能群组的协同相互作用，其中一些可能与表现更密切相关，而另一些则可能在任务约束下发挥更普遍的功能。
