Thresholds for activation of rabbit retinal ganglion cells with relatively large, extracellular microelectrodes
Thresholds for activation of rabbit retinal ganglion cells with relatively large, extracellular microelectrodes
复制标题
DOI：
10.1167/iovs.04-1018
复制
发表时间：
2005-04-01
影响因子：
4.4
通讯作者：
Rizzo, JF
中科院分区：
文献类型：
--
作者：
Jensen, RJ;Ziv, OR;Rizzo, JF
目的.为了研究视网膜神经节细胞（RGC）对电刺激的反应，使用与人体研究中使用的电极尺寸相当的电极，研究电子视网膜假体的可行性。在体外用125和500 μ m直径的电极将电流脉冲施加到内表面刺激兔视网膜，同时在细胞外记录RGC的反应。短潜伏期（SL;在RGC的感受野内电刺激后观察到长潜伏期（LL; >= 9 ms）反应。在0.1 ms的短电流脉冲下，SL单元响应的阈值电流显着低于LL单元响应的阈值电流。对于长脉冲（10- 20-ms），SL和LL细胞响应的阈值电流非常相似。当电极从最低电阈值点（位于视网膜表面上方或沿着视网膜表面）移位时，SL细胞响应的阈值电流比LL细胞响应的阈值电流增加得更急剧。刺激细胞感受野外的RGC轴突只产生SL反应。对于0.1毫秒持续时间的脉冲，轴突响应的阈值电流显着高于SL细胞响应的阈值电流。在脉冲持续时间> 1 ms时，阈值非常相似。RGC对电刺激的响应取决于电流脉冲持续时间和刺激电极的位置。对于视网膜前假体，短持续时间的电流脉冲可能是优选的，因为它们导致视网膜的更局部的激活。
PURPOSE. To investigate the responses of retinal ganglion cells (RGCs) to electrical stimulation, using electrodes comparable in size to those used in human studies investigating the feasibility of an electronic retinal prosthesis.METHODS. Rabbit retinas were stimulated in vitro with current pulses applied to the inner surface with 125- and 500-mu m diameter electrodes while the responses of RGCs were recorded extracellularly.RESULTS. Both short-latency (SL; 3-5 ms) and long-latency (LL; >= 9 ms) responses were observed after electrical stimulation within the receptive field of an RGC. With short, 0.1-ms current pulses, the threshold current for the SL cell response was significantly lower than that for the LL cell response. With long (10- to 20-ms) pulses, the threshold currents for the SL and LL cell responses were very similar. The threshold current for the SL cell response increased more steeply than did the LL cell response when the electrode was displaced from the point of lowest electrical threshold, either above or along the surface of the retina. Stimulation of an RGC axon outside of the cell's receptive field produced only an SL response. For 0.1-ms duration pulses, the threshold current for the axonal response was significantly higher than the threshold current for the SL cell response. At pulse durations > 1 ms, the thresholds were very similar.CONCLUSIONS. RGC responses to electrical stimulation depend on the current pulse duration and location of the stimulating electrode. For an epiretinal prosthesis, short-duration current pulses may be preferable since they result in a more localized activation of the retina.