SGER: Biophotonics: Study of Transcorneal Electrical Stimulation in Subjects with Retinitis Pigmentosa

0917458 Tsang眼睛捕捉光线，但大脑是体验视觉的地方。视网膜假体恢复盲人部分视力的能力已在视网膜水平得到证实，但在视网膜退行性疾病导致的长时间视觉剥夺后，大脑如何接受新的神经信息尚不清楚。视网膜退行性疾病中发生的神经重塑可能对视网膜假体在视觉恢复中的有用性产生影响。由视杆细胞、视锥细胞或视网膜色素上皮细胞中的基因缺陷引发的哺乳动物视网膜变性通常触发光感受器的丧失;因此，有效地使神经视网膜没有感觉输入。神经视网膜通过重塑来应对这一挑战，首先是神经元结构的细微变化，然后是大规模重组。这类视网膜重塑可改变视网膜内正常的光传输路径，并导致不同的神经节细胞群在光和电刺激之间被激活。在此建议中，PI建议使用经角膜电刺激（TcES），通过穿过角膜的电流直接刺激视网膜神经节细胞来探测视网膜与视觉皮层之间的神经连接。通过使用正电子发射断层扫描（PET）和18 F-氟脱氧葡萄糖（FDG）比较RP患者视网膜光刺激和电刺激之间的大脑激活，我们将加深对视网膜重塑如何反映在视觉皮质中的了解。这项研究可以帮助我们深入了解视网膜退行性过程导致的皮质重组。

0917458TsangThe eye captures light but the brain is where vision is experienced. The capacity of retinal prostheses to restore some vision in blind individuals has been demonstrated at the retinal level, but it is unknown how the brain will be receptive to the new neural message after a prolonged period of visual deprivation resulting from retinal degenerative diseases. Neural remodeling that occurs in retinal degenerative diseases can have an impact on the usefulness of retinal prostheses in visual restoration. Mammalian retinal degenerations, initiated by gene defects in rods, cones or the retinal pigmented epithelium, often trigger loss of the photoreceptors; thus, effectively leaving the neural retina without sensory input. The neural retina responds to this challenge by remodeling, first by subtle changes in neuronal structure and later by large-scale reorganization. This type of retinal remodeling can alter normal light transmission pathway in the retina and result in activation of different ganglion cell groups between light and electrical stimulation.In this proposal, the PI proposes to use transcorneal electrical stimulation (TcES) to probe the neural connection between the retina and the visual cortex via direct stimulation of the retinal ganglion cells from a current passing through the cornea. By using positron emission tomography (PET) and 18F-fluorodeoxyglucose (FDG) to compare brain activation between light stimulation and electrical stimulation of the retina in patients with RP, we will be increase our understanding how retinal remodeling is reflected in the visual cortex. The study can then help us gain insight into cortical reorganization resulting from the retinal degenerative process.