Significance: Infrared neural stimulation (INS) utilizes pulsed infrared light to selectively elicit neural activity without exogenous compounds. Despite its versatility in a broad range of biomedical applications, no comprehensive comparison of factors pertaining to the efficacy and safety of INS such as wavelength, radiant exposure, and optical spot size exists in the literature. Aim: Here, we evaluate these parameters using three of the wavelengths commonly used for INS, 1450 nm, 1875 nm, and 2120 nm. Approach: In an in vivo rat sciatic nerve preparation, the stimulation threshold and transition rate to 100% activation probability were used to compare the effects of each parameter. Results: The pulsed diode lasers at 1450 nm and 1875 nm had a consistently higher (∼1.0 J / cm2) stimulation threshold than that of the Ho:YAG laser at 2120 nm (∼0.7 J / cm2). In addition, the Ho:YAG produced a faster transition rate to 100% activation probability compared to the diode lasers. Our data suggest that the superior performance of the Ho:YAG is a result of the high-intensity microsecond spike at the onset of the pulse. Acute histological evaluation of diode irradiated nerves revealed a safe range of radiant exposures for stimulation. Conclusion: Together, our results identify measures to improve the safety, efficacy, and accessibility of INS technology for research and clinical applications.

中文翻译：

---

确定周围神经系统红外神经刺激的最佳参数

意义：红外神经刺激 (INS) 利用脉冲红外光选择性引发神经活动，无需外源化合物。尽管INS在广泛的生物医学应用中具有多功能性，但文献中没有对与INS的功效和安全性有关的因素（例如波长、辐射暴露和光斑尺寸）进行全面比较。目标：在这里，我们使用 INS 常用的三种波长（1450 nm、1875 nm 和 2120 nm）来评估这些参数。方法：在体内大鼠坐骨神经制剂中，使用刺激阈值和 100% 激活概率的转换率来比较每个参数的效果。结果：1450 nm 和 1875 nm 的脉冲二极管激光器的刺激阈值（~1.0 J/cm2）始终高于 2120 nm 的 Ho:YAG 激光器（~0.7 J/cm2）。此外，与二极管激光器相比，Ho:YAG 具有更快的 100% 激活概率转变速率。我们的数据表明，Ho:YAG 的卓越性能是脉冲开始时高强度微秒尖峰的结果。对二极管照射神经的急性组织学评估揭示了刺激辐射暴露的安全范围。结论：我们的研究结果共同确定了提高 INS 技术研究和临床应用的安全性、有效性和可及性的措施。