Local signaling from a retinal prosthetic in a rodent retinitis pigmentosa model in vivo.
Local signaling from a retinal prosthetic in a rodent retinitis pigmentosa model in vivo.
复制标题
啮齿动物体内色素性视网膜炎模型中视网膜假体的局部信号传导。
DOI：
10.1088/1741-2560/11/4/046012
复制
发表时间：
2014
影响因子：
4
通讯作者：
McCall,MaureenA
中科院分区：
文献类型：
--
作者：
Fransen,JamesW;Pangeni,Gobinda;Pardue,MachelleT;McCall,MaureenA
ObjectiveIn clinical trials, retinitis pigmentosa patients implanted with a retinal prosthetic device show enhanced spatial vision, including the ability to read large text and navigate. New prosthetics aim to increase spatial resolution by decreasing pixel/electrode size and limiting current spread. To examine spatial resolution of a new prosthetic design, we characterized and compared two photovoltaic array (PVA) designs and their interaction with the retina after subretinal implantation in transgenic S334ter line 3 rats (Tg S334ter-3).ApproachPVAs were implanted subretinally at two stages of degeneration and assessed in vivo using extracellular recordings in the superior colliculus (SC). Several aspects of this interaction were evaluated by varying duration, irradiance and position of a near infrared laser focused on the PVA. These characteristics included: activation threshold, response linearity, SC signal topography and spatial localization. The major design difference between the two PVA designs is the inclusion of local current returns in the newer design.Main resultsWhen tested in vivo, PVA-evoked response thresholds were independent of pixel/electrode size, but differ between the new and old PVA designs. Response thresholds were independent of implantation age and duration (⩽ 7.5 months). For both prosthesis designs, threshold intensities were within established safety limits. PVA-evoked responses require inner retina synaptic transmission and do not directly activate retinal ganglion cells. The new PVA design evokes local retinal activation, which is not found with the older PVA design that lacks local current returns.SignificanceOur study provides in vivo evidence that prosthetics make functional contacts with the inner nuclear layer at several stages of degeneration. The new PVA design enhances local activation within the retina and SC. Together these results predict that the new design can potentially harness the inherent processing within the retina and is likely to produce higher spatial resolution in patients.
