The vertebrate brain comprises a plethora of cell types connected by intertwined pathways. Optogenetics enriches the neuroscientific tool set for disentangling these neuronal circuits in a manner which exceeds the spatio-temporal precision of previously existing techniques. Technically, optogenetics can be divided in three types of optical and genetic combinations: (1) it is primarily understood as the manipulation of the activity of genetically modified cells (typically neurons) with light, i.e. optical actuators. (2) A second combination refers to visualizing the activity of genetically modified cells (again typically neurons), i.e. optical sensors. (3) A completely different interpretation of optogenetics refers to the light activated expression of a genetically induced construct. Here, we focus on the first two types of optogenetics, i.e. the optical actuators and sensors in an attempt to give an overview into the topic. We first cover methods to express opsins into neurons and introduce strategies of targeting specific neuronal populations in different animal species. We then summarize combinations of optogenetics with behavioral read out and neuronal imaging. Finally, we give an overview of the current state-of-the-art and an outlook on future perspectives.

脊椎动物的大脑包含通过交织的途径连接的大量细胞类型。光遗传学丰富了神经科学工具集，用于以超过现有技术的时空精度的方式解开这些神经元回路。从技术上讲，光遗传学可分为三种类型的光学和遗传组合：（1）主要理解为通过光即光学致动器来操纵基因修饰的细胞（通常是神经元）的活性。（2）第二种组合是指可视化转基因细胞（通常也是神经元）的活动，即光学传感器。（3）对光遗传学的完全不同的解释是指基因诱导的构建体的光激活表达。在这里，我们关注前两种类型的光遗传学，即 光学致动器和传感器，以试图对该主题进行概述。我们首先介绍将视蛋白表达为神经元的方法，并介绍针对不同动物物种中特定神经元种群的策略。然后，我们总结了光遗传学与行为读取和神经元成像的组合。最后，我们概述了当前的最新技术以及对未来观点的展望。