Wraga Maryjane, Shephard Jennifer M, Church Jessica A, Inati Souheil, Kosslyn Stephen M
Department of Psychology, Smith College, Science Center, Bass Hall 304, Northampton, MA 01063, USA.
Neuropsychologia. 2005;43(9):1351-61. doi: 10.1016/j.neuropsychologia.2004.11.028. Epub 2005 Jan 20.
This study used functional magnetic resonance imaging (fMRI) to investigate the neural mechanisms underlying two types of spatial transformations: imagined object rotations and imagined rotations of the self about an object. Participants viewed depictions of single three-dimensional Shepard--Metzler objects situated within a sphere. A T-shaped prompt appeared outside of the sphere at different locations across trials. In the object rotation task, participants imagined rotating the object so that one of its ends was aligned with the prompt. They then judged whether a textured portion of the object would be visible in its new orientation. In the self rotation task, they imagined rotating themselves to the location of the T-prompt, and then judged whether a textured portion of the object would be visible from the new viewpoint. Activation in both tasks was compared to respective control conditions in which identical judgments were made without rotation. A direct comparison of self and object rotation tasks revealed activation spreading from left premotor to left primary motor (M1) cortex (areas 6/4) for imagined object rotations, but not imagined self rotations. In contrast, the self rotation task activated left supplementary motor area (SMA; area 6). In both transformations, activation also occurred in other regions. These findings provide evidence for multiple spatial-transformation mechanisms within the human cognitive system.
本研究使用功能磁共振成像（fMRI）来探究两种空间变换背后的神经机制：想象物体旋转以及想象自我围绕物体旋转。参与者观看位于球体中的单个三维谢泼德－梅茨勒物体的描绘图像。在不同试验中，一个T形提示出现在球体外的不同位置。在物体旋转任务中，参与者想象旋转物体，使其一端与提示对齐。然后他们判断物体的一个有纹理部分在其新方向上是否可见。在自我旋转任务中，他们想象自己旋转到T形提示的位置，然后判断从新视角是否能看到物体的一个有纹理部分。将这两个任务中的激活情况与各自的对照条件进行比较，在对照条件下，不进行旋转做出相同判断。对自我旋转任务和物体旋转任务的直接比较显示，对于想象物体旋转，激活从左前运动皮层扩散到左初级运动（M1）皮层（6区/4区），但想象自我旋转时并非如此。相反，自我旋转任务激活了左辅助运动区（SMA；6区）。在这两种变换中，其他区域也出现了激活。这些发现为人类认知系统内多种空间变换机制提供了证据。
