Shin Younghoon, Yoo Minsu, Kim Hyung-Sun, Nam Sung-Ki, Kim Hyoung-Ihl, Lee Sun-Kyu, Kim Sohee, Kwon Hyuk-Sang
Department of Biomedical Science and Engineering, and Gwangju Institute of Science and Technology (GIST), 123 Cheomdan-Gwagiro, Buk-Gu, Gwangju 61005, South Korea.
Graduate Program in Computational Neuroscience, University of Chicago, Chicago, Illinois 60637, USA.
Biomed Opt Express. 2016 Oct 6;7(11):4450-4471. doi: 10.1364/BOE.7.004450. eCollection 2016 Nov 1.
Understanding light intensity and temperature increase is of considerable importance in designing or performing optogenetic experiments. Our study describes the optimal light power at target depth in the rodent brain that would maximize activation of light-gated ion channels while minimizing temperature increase. Monte Carlo (MC) simulations of light delivery were used to provide a guideline for suitable light power at a target depth. In addition, MC simulations with the Pennes bio-heat model using data obtained from measurements with a temperature-measuring cannula having 12.3 mV/°C of thermoelectric sensitivity enabled us to predict tissue heating of 0.116 °C/mW on average at target depth of 563 μm and specifically, a maximum mean plateau temperature increase of 0.25 °C/mW at 100 μm depth for 473 nm light. Our study will help to improve the design and performance of optogenetic experiments while avoiding potential over- and under-illumination.
在设计或进行光遗传学实验时，了解光强度和温度升高具有相当重要的意义。我们的研究描述了啮齿动物大脑目标深度处的最佳光功率，该功率可在使温度升高最小化的同时，最大程度地激活光门控离子通道。利用光传输的蒙特卡洛（MC）模拟为目标深度处的合适光功率提供指导。此外，使用具有12.3 mV/°C热电灵敏度的温度测量套管测量获得的数据，通过Pennes生物热模型进行的MC模拟使我们能够预测在563μm目标深度处平均组织加热为0.116°C/mW，具体而言，对于473nm光，在100μm深度处最大平均平台温度升高为0.25°C/mW。我们的研究将有助于改进光遗传学实验的设计和性能，同时避免潜在的过度照明和照明不足。
