Interactions of Prosthetic and Natural Vision in Animals With Local Retinal Degeneration
Interactions of Prosthetic and Natural Vision in Animals With Local Retinal Degeneration
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DOI：
10.1167/iovs.15-17521
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发表时间：
2015-11-01
影响因子：
4.4
通讯作者：
Palanker, Daniel
中科院分区：
文献类型：
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作者：
Lorach, Henri;Lei, Xin;Palanker, Daniel
目的.部分感觉丧失的假体恢复导致人工和自然输入之间的相互作用。理想情况下，康复应该允许两种形式的感知融合。在这里，我们研究了正常和假体视觉的局部视网膜变性的啮齿动物模型之间的相互作用。在视力正常的大鼠视网膜下腔植入光伏阵列，诱导芯片上方的光感受器局部变性，该区域的视网膜内神经元由近红外（NIR）光供电的光伏植入物电刺激。我们研究了假体和自然视觉诱发电位（VEP）的反应，同时刺激的近红外和可见光图案。我们证明，电和自然VEP线性相加的视觉皮层，和两个反应下较亮的环境光下降。对可见光闪光的反应增加了3个数量级的对比度（闪光/背景），而对于电刺激，对比度范围仅限于1个数量级。在视网膜上相同区域，假体VEP的最大振幅比对可见闪光的最大反应低三倍。环境光影响假肢的反应，虽然远低于对可见刺激的反应。视觉场景中对比度的假体表示可以在有限的程度上通过适当校准的刺激强度进行编码，这也取决于环境光条件。这种校准对于将中央假体视力与自然周边视力相结合的患者（例如年龄相关性黄斑变性患者）将是重要的。
PURPOSE. Prosthetic restoration of partial sensory loss leads to interactions between artificial and natural inputs. Ideally, the rehabilitation should allow perceptual fusion of the two modalities. Here we studied the interactions between normal and prosthetic vision in a rodent model of local retinal degeneration.METHODS. Implantation of a photovoltaic array in the subretinal space of normally sighted rats induced local degeneration of the photoreceptors above the chip, and the inner retinal neurons in this area were electrically stimulated by the photovoltaic implant powered by near-infrared (NIR) light. We studied prosthetic and natural visually evoked potentials (VEP) in response to simultaneous stimulation by NIR and visible light patterns.RESULTS. We demonstrate that electrical and natural VEPs summed linearly in the visual cortex, and both responses decreased under brighter ambient light. Responses to visible light flashes increased over 3 orders of magnitude of contrast (flash/background), while for electrical stimulation the contrast range was limited to 1 order of magnitude. The maximum amplitude of the prosthetic VEP was three times lower than the maximum response to a visible flash over the same area on the retina.CONCLUSIONS. Ambient light affects prosthetic responses, albeit much less than responses to visible stimuli. Prosthetic representation of contrast in the visual scene can be encoded, to a limited extent, by the appropriately calibrated stimulus intensity, which also depends on the ambient light conditions. Such calibration will be important for patients combining central prosthetic vision with natural peripheral sight, such as in age-related macular degeneration.