Press W A, Brewer A A, Dougherty R F, Wade A R, Wandell B A
Psychology Department, Stanford University, Jordan Hall, Building 420, Stanford, CA 94305, USA.
Vision Res. 2001;41(10-11):1321-32. doi: 10.1016/s0042-6989(01)00074-8.
Functional MRI measurements can securely partition the human posterior occipital lobe into retinotopically organized visual areas (V1, V2 and V3) with experiments that last only 30 min. Methods for identifying functional areas in the dorsal and ventral aspect of the human occipital cortex, however, have not achieved this level of precision; in fact, different laboratories have produced inconsistent reports concerning the visual areas in dorsal and ventral occipital lobe. We report four findings concerning the visual representation in dorsal regions of occipital cortex. First, cortex near area V3A contains a central field representation that is distinct from the foveal representation at the confluence of areas V1, V2 and V3. Second, adjacent to V3A there is a second visual area, V3B, which represents both the upper and lower quadrants. The central representation in V3B appears to merge with that of V3A, much as the central representations of V1/2/3 come together on the lateral margin of the posterior pole. Third, there is yet another dorsal representation of the central visual field. This representation falls in area V7, which includes a representation of both the upper and lower quadrants of the visual field. Fourth, based on visual field and spatial summation measurements, it appears that the receptive field properties of neurons in area V7 differ from those in areas V3A and V3B.
功能磁共振成像测量能够通过仅持续30分钟的实验，将人类枕叶后部可靠地划分为按视网膜拓扑组织的视觉区域（V1、V2和V3）。然而，用于识别人类枕叶皮质背侧和腹侧功能区域的方法尚未达到这种精确程度；事实上，不同实验室关于枕叶背侧和腹侧视觉区域的报告并不一致。我们报告了关于枕叶皮质背侧区域视觉表征的四项发现。第一，V3A区域附近的皮质包含一个中央视野表征，它与V1、V2和V3区域交汇处的中央凹表征不同。第二，在V3A附近有第二个视觉区域V3B，它同时代表上象限和下象限。V3B中的中央表征似乎与V3A的中央表征融合，就像V1/2/3的中央表征在后极外侧边缘汇聚一样。第三，中央视野还有另一种背侧表征。这种表征位于V7区域，该区域包括视野上象限和下象限的表征。第四，基于视野和空间总和测量，V7区域神经元的感受野特性似乎与V3A和V3B区域的不同。
