Stujenske Joseph M, Spellman Timothy, Gordon Joshua A
Graduate Program in Neurobiology and Behavior, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA.
Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10021, USA.
Cell Rep. 2015 Jul 21;12(3):525-34. doi: 10.1016/j.celrep.2015.06.036. Epub 2015 Jul 9.
Despite the increasing use of optogenetics in vivo, the effects of direct light exposure to brain tissue are understudied. Of particular concern is the potential for heat induced by prolonged optical stimulation. We demonstrate that high-intensity light, delivered through an optical fiber, is capable of elevating firing rate locally, even in the absence of opsin expression. Predicting the severity and spatial extent of any temperature increase during optogenetic stimulation is therefore of considerable importance. Here, we describe a realistic model that simulates light and heat propagation during optogenetic experiments. We validated the model by comparing predicted and measured temperature changes in vivo. We further demonstrate the utility of this model by comparing predictions for various wavelengths of light and fiber sizes, as well as testing methods for reducing heat effects on neural targets in vivo.
尽管光遗传学在体内的应用越来越广泛，但直接光照对脑组织的影响仍未得到充分研究。特别值得关注的是长时间光刺激引起的热效应。我们证明，通过光纤传输的高强度光能够局部提高放电率，即使在没有视蛋白表达的情况下也是如此。因此，预测光遗传学刺激期间任何温度升高的严重程度和空间范围具有相当重要的意义。在这里，我们描述了一个逼真的模型，该模型模拟光遗传学实验期间的光和热传播。我们通过比较体内预测和测量的温度变化来验证该模型。我们还通过比较不同波长的光和光纤尺寸的预测结果，以及测试减少体内热效应影响神经靶点的方法，进一步证明了该模型的实用性。
