Triple visual hemifield maps in a case of optic chiasm hypoplasia
Triple visual hemifield maps in a case of optic chiasm hypoplasia
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DOI：
10.1016/j.neuroimage.2020.116822
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发表时间：
2020-07-15
期刊：
影响因子：
5.7
通讯作者：
Hoffmann, Michael B.
中科院分区：
文献类型：
--
作者：
Ahmadi, Khazar;Fracasso, Alessio;Hoffmann, Michael B.
在人类中，每个半球都包含对侧视野的两张视觉专题图的叠加，每只眼睛一张。视觉皮层的容量是否仅限于这两个地图，或者塑料机制是否可用于容纳更多地图？我们确定了一个患有交叉发育不全的罕见个体的视野图的皮质组织，其中视觉皮层可塑性面临着适应三个半视野图的挑战。使用 7T 的高分辨率功能磁共振成像和 3T 的扩散加权 MRI，我们发现三个半视网膜输入（而不是正常的两个）汇聚到左半球。基于 fMRI 的左侧 V1-V3 在 3T 时的群体感受野映射显示了左侧视觉皮层中的三个叠加的半场表征，即来自左眼的相对视觉半场的两个表征和来自右眼的一个右半场表征。我们的结论是，发育可塑性，包括局部内部和皮质-皮质连接的重新布线，对于支持一个半球内三个半场地图的共存和功能至关重要。
In humans, each hemisphere comprises an overlay of two visuotopic maps of the contralateral visual field, one from each eye. Is the capacity of the visual cortex limited to these two maps or are plastic mechanisms available to host more maps? We determined the cortical organization of the visual field maps in a rare individual with chiasma hypoplasia, where visual cortex plasticity is challenged to accommodate three hemifield maps. Using high-resolution fMRI at 7T and diffusion-weighted MRI at 3T, we found three hemiretinal inputs, instead of the normal two, to converge onto the left hemisphere. fMRI-based population receptive field mapping of the left V1–V3 at 3T revealed three superimposed hemifield representations in the left visual cortex, i.e. two representations of opposing visual hemifields from the left eye and one right hemifield representation from the right eye. We conclude that developmental plasticity including the re-wiring of local intra- and cortico-cortical connections is pivotal to support the coexistence and functioning of three hemifield maps within one hemisphere.