The visual cortical responses to sinusoidal transcorneal electrical stimulation

• Published in: Brain research 2022-06, Vol.1785, p.147875-147875, Article 147875
• Main Authors: Su, Xiaofan, Zhou, Meixuan, Di, Liqing, Chen, Jianpin, Zhai, Zhenzhen, Liang, Junling, Li, Liming, Li, Heng, Chai, Xinyu
• Format: Article
• Language: English
• Subjects: Electric Stimulation - methods; Humans; Optical intrinsic signal imaging; Retina - physiology; Retinal Degeneration; Retinal neuromodulation; Retinal stimulation; Sinusoidal stimulation; Visual Cortex - physiology; Visual cortical responses
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2022.147875

•It is the first time to investigate the responses arising in visual cortex to sinusoidal retinal electrostimulation, and to compare the different cortical responses elicited by sinusoidal and rectangular waveforms in vivo.•The optimal stimulation frequency for sinusoidal retinal electrostimulation was approximately 20 Hz.•Sinusoidal retinal electrostimulation is a more efficient strategy than rectangular stimulation in regard to cortical response, especially at low frequency. Retinal stimulation has become a widely utilized approach to restore visual function for individuals with retinal degenerative diseases. Although the rectangular electrical pulse is the primary stimulus waveform used in retinal neuromodulation, it remains unclear whether alternate waveforms may be more effective. Here, we used the optical intrinsic signal imaging system to assess the responses of cats’ visual cortex to sinusoidal electrical stimulation through contact lens electrode, analyzing the response to various stimulus parameters (frequency, intensity, pulse width). A comparison between sinusoidal and rectangular stimulus waveform was also investigated. The results indicated that the optimal stimulation frequency for sinusoidal electrical stimulation was approximately 20 Hz, supporting the hypothesis that low-frequency electrostimulation induces more responsiveness in retinal neurons than high-frequency electrostimulation in case of sinusoidal stimulation. We also demonstrated that for low-frequency retinal neuromodulation, sinusoidal pulses are more effective than rectangular ones. In addition, we found that compared to current intensity, the effect of the sinusoidal pulse width on cortical responses was more prominent. These results suggested that sinusoidal electrical stimulation may provide a promising strategy for improved retinal neuromodulation in clinical settings.