Biological Complex Systems Laboratory, Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-8561, Japan.
J Neurophysiol. 2009 Nov;102(5):2704-18. doi: 10.1152/jn.00102.2009. Epub 2009 Jul 8.
Human neuroimaging experiments typically localize motion-selective cortex (MT+) by contrasting responses to stationary and moving stimuli. It has long been suspected that MT+, located on the lateral surface at the temporal-occipital (TO) boundary, contains several distinct visual field maps, although only one coarse map has been measured. Using a novel functional MRI model-based method we identified two maps-TO-1 and TO-2-and measured population receptive field (pRF) sizes within these maps. The angular representation of the first map, TO-1, has a lower vertical meridian on its posterior side at the boundary with the lateral-occipital cortex (i.e., the LO-2 portion). The angular representation continues through horizontal to the upper vertical meridian at the boundary with the second map, TO-2. The TO-2 angle map reverses from upper to lower visual field at increasingly anterior positions. The TO maps share a parallel eccentricity map in which center-to-periphery is represented in the ventral-to-dorsal direction; both maps have an expanded foveal representation. There is a progressive increase in the pRF size from V1/2/3 to LO-1/2 and TO-1/2, with the largest pRF sizes in TO-2. Further, within each map the pRF size increases as a function of eccentricity. The visual field coverage of both maps extends into the ipsilateral visual field, with larger sensitivity to peripheral ipsilateral stimuli in TO-2 than that in TO-1. The TO maps provide a functional segmentation of human motion-sensitive cortex that enables a more complete characterization of processing in human motion-selective cortex.
人类神经影像学实验通常通过对比静止和运动刺激的反应来定位运动选择性皮层(MT+)。长期以来,人们一直怀疑位于颞枕(TO)边界外侧表面的 MT+包含几个不同的视野图,尽管只测量了一个粗略的图。使用一种新的基于功能磁共振成像模型的方法,我们确定了两个图-TO-1 和 TO-2-并测量了这些图内的群体感受野(pRF)大小。第一个图,TO-1 的角度表示,在与外侧枕叶(即 LO-2 部分)交界处的后侧具有较低的垂直子午线。角度表示通过水平延伸到与第二个图,TO-2 的垂直子午线的上边界。TO-2 的角度图从前到后在越来越靠前的位置从上部视野反转到下部视野。TO 图共享一个平行的偏心图,其中中心到外围在腹侧到背侧方向上表示;两个图都有一个扩展的中央凹表示。从 V1/2/3 到 LO-1/2 和 TO-1/2,pRF 大小逐渐增加,TO-2 中的 pRF 大小最大。此外,在每个图中,pRF 大小随偏心度的增加而增加。两个图的视野覆盖范围都扩展到对侧视野,TO-2 对周边对侧刺激的敏感性大于 TO-1。TO 图为人类运动敏感皮层提供了功能分割,使我们能够更完整地描述人类运动选择性皮层中的处理过程。