Topographic maps in human frontal cortex revealed in memory-guided saccade and spatial working-memory tasks
Topographic maps in human frontal cortex revealed in memory-guided saccade and spatial working-memory tasks
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DOI：
10.1152/jn.00010.2007
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发表时间：
2007-05-01
影响因子：
2.5
通讯作者：
Schneider, Keith A.
中科院分区：
文献类型：
--
作者：
Kastner, Sabine;DeSimone, Kevin;Schneider, Keith A.
我们使用3特斯拉和改进的空间分辨率（2 x 2 x 2 mm（3））的fMRI，通过在围绕中心注视点顺时针排列的8或12个外围位置进行记忆引导反应任务，研究人类额叶皮层的地形组织。这些任务需要记住一个外围目标的位置几秒钟，之后受试者要么对记住的位置进行眼跳（记忆引导眼跳任务），要么通过按下按钮来判断测试刺激是否出现在相同或略有不同的位置（空间工作记忆任务）。通过这些任务，我们在每个半球发现了两个地形图，一个在中央前皮质的上级分支和上级额沟的caudalmost部分，在人类额叶眼区，第二个在中央前皮质的下级分支和额下沟的caudalmost部分，这两个都与视觉引导的扫视引起的激活有很大的重叠。在每个图中，激活的体素主要在对侧半场中针对扫视方向和记忆位置进行编码，其中相邻扫视方向和记忆位置表示在图的相邻位置中。特定的眼跳方向或记忆的位置通常在地图的多个位置中表示。地形激活模式显示个体差异从受试者到受试者，但在受试者内是可重复的。值得注意的是，只有眼跳相关的激活，但没有地形组织，被发现在该地区的人类补充眼领域的背内侧前额叶皮层。总之，这些结果表明，地形组织可以揭示外部的感觉皮质区使用更复杂的行为任务。
We used fMRI at 3 Tesla and improved spatial resolution (2 x 2 x 2 mm(3)) to investigate topographic organization in human frontal cortex using memory-guided response tasks performed at 8 or 12 peripheral locations arranged clockwise around a central fixation point. The tasks required the location of a peripheral target to be remembered for several seconds after which the subjects either made a saccade to the remembered location (memoryguided saccade task) or judged whether a test stimulus appeared in the same or a slightly different location by button press (spatial workingmemory task). With these tasks, we found two topographic maps in each hemisphere, one in the superior branch of precentral cortex and caudalmost part of the superior frontal sulcus, in the region of the human frontal eye field, and a second in the inferior branch of precentral cortex and caudalmost part of the inferior frontal sulcus, both of which greatly overlapped with activations evoked by visually guided saccades. In each map, activated voxels coded for saccade directions and memorized locations predominantly in the contralateral hemifield with neighboring saccade directions and memorized locations represented in adjacent locations of the map. Particular saccade directions or memorized locations were often represented in multiple locations of the map. The topographic activation patterns showed individual variability from subject to subject but were reproducible within subjects. Notably, only saccade-related activation, but no topographic organization, was found in the region of the human supplementary eye field in dorsomedial prefrontal cortex. Together these results show that topographic organization can be revealed outside sensory cortical areas using more complex behavioral tasks.