Kanda Hiroyuki, Morimoto Takeshi, Fujikado Takashi, Tano Yasuo, Fukuda Yutaka, Sawai Hajime
Department of Physiology and Biosignaling, Graduate School of Medicine, Osaka University, Suita, Japan.
Invest Ophthalmol Vis Sci. 2004 Feb;45(2):560-6. doi: 10.1167/iovs.02-1268.
Assessment of a novel method of retinal stimulation, known as suprachoroidal-transretinal stimulation (STS), which was designed to minimize insult to the retina by implantation of stimulating electrodes for artificial vision.
In 17 normal hooded rats and 12 Royal College of Surgeons (RCS) rats, a small area of the retina was focally stimulated with electric currents through an anode placed on the fenestrated sclera and a cathode inserted into the vitreous chamber. Evoked potentials (EPs) in response to STS were recorded from the surface of the superior colliculus (SC) with a silver-ball electrode, and their physiological properties and localization were studied.
In both normal and RCS rats, STS elicited triphasic EPs that were vastly diminished by changing polarity of stimulating electrodes and abolished by transecting the optic nerve. The threshold intensity (C) of the EP response to STS was approximately 7.2 +/- 2.8 nC in normal and 12.9 +/- 7.7 nC in RCS rats. The responses to minimal STS were localized in an area on the SC surface measuring 0.12 +/- 0.07 mm(2) in normal rats and 0.24 +/- 0.12 mm(2) in RCS rats. The responsive area corresponded retinotopically to the retinal region immediately beneath the anodic stimulating electrode.
STS is less invasive in the retina than stimulation through epiretinal or subretinal implants. STS can generate focal excitation in retinal ganglion cells in normal animals and in those with degenerated photoreceptors, which suggests that this method of retinal stimulation is suitable for artificial vision.
评估一种新型视网膜刺激方法，即脉络膜上视网膜刺激（STS），该方法旨在通过植入刺激电极实现人工视觉，从而将对视网膜的损伤降至最低。
在17只正常带帽大鼠和12只皇家外科学院（RCS）大鼠中，通过置于开窗巩膜上的阳极和插入玻璃体内腔的阴极，用电流对视网膜的一小区域进行局部刺激。用银球电极从丘脑上核（SC）表面记录对STS的诱发电位（EPs），并研究其生理特性和定位。
在正常大鼠和RCS大鼠中，STS均引发三相EPs，通过改变刺激电极的极性可使其大幅减弱，切断视神经则可将其消除。正常大鼠对STS的EP反应阈值强度（C）约为7.2±2.8 nC，RCS大鼠为12.9±7.7 nC。对最小STS的反应定位在SC表面的一个区域，正常大鼠中该区域面积为0.12±0.07 mm²，RCS大鼠中为0.24±0.12 mm²。反应区域在视网膜上与阳极刺激电极正下方的视网膜区域呈视网膜拓扑对应。
与通过视网膜表面或视网膜下植入物进行刺激相比，STS对视网膜的侵入性较小。STS可在正常动物和光感受器退化的动物的视网膜神经节细胞中产生局部兴奋，这表明这种视网膜刺激方法适用于人工视觉。
