Ryu Sang Baek, Choi Jeong Woo, Ahn Kun No, Goo Yong Sook, Kim Kyung Hwan
Department of Biomedical Engineering, Yonsei University Wonju College of Health Science, Wonju, Korea.
Department of Physiology, Chungbuk National University School of Medicine, Cheongju, Korea.
J Korean Med Sci. 2017 Jun;32(6):900-907. doi: 10.3346/jkms.2017.32.6.900.
Retinal implants have been developed as a promising way to restore partial vision for the blind. The observation and analysis of neural activities can offer valuable insights for successful prosthetic electrical stimulation. Retinal ganglion cell (RGC) activities have been investigated to provide knowledge on the requirements for electrical stimulation, such as threshold current and the effect of stimulation waveforms. To develop a detailed 'stimulation strategy' for faithful delivery of spatiotemporal visual information to the brain, it is essential to examine both the temporal and spatial characteristics of RGC responses, whereas previous studies were mainly focused on one or the other. In this study, we investigate whether the spatiotemporal visual information can be decoded from the RGC network activity evoked by patterned electrical stimulation. Along with a thorough characterization of spatial spreading of stimulation current and temporal information encoding, we demonstrated that multipixel spatiotemporal visual information can be accurately decoded from the population activities of RGCs stimulated by amplitude-modulated pulse trains. We also found that the details of stimulation, such as pulse amplitude range and pulse rate, were crucial for accurate decoding. Overall, the results suggest that useful visual function may be restored by amplitude modulation-based retinal stimulation.
视网膜植入物已被开发成为一种有望为盲人恢复部分视力的方法。对神经活动的观察和分析可为成功的假体电刺激提供有价值的见解。人们已经对视网膜神经节细胞（RGC）的活动进行了研究，以了解电刺激的要求，如阈值电流和刺激波形的影响。为了制定一个详细的“刺激策略”，以便将时空视觉信息准确地传递到大脑，研究RGC反应的时间和空间特征至关重要，而以前的研究主要集中在其中一个方面。在本研究中，我们调查了是否可以从图案化电刺激诱发的RGC网络活动中解码时空视觉信息。除了对刺激电流的空间扩散和时间信息编码进行全面表征外，我们还证明了多像素时空视觉信息可以从由幅度调制脉冲序列刺激的RGC群体活动中准确解码。我们还发现，刺激的细节，如脉冲幅度范围和脉冲频率，对于准确解码至关重要。总体而言，结果表明基于幅度调制的视网膜刺激可能恢复有用的视觉功能。
