ABSTRACT

Optogenetic technology uses light to control or modulate neuronal function, providing a means of interacting with neurons that is unchallenged in its temporal resolution, spatial resolution, and cell type specificity. Optogenetic experiments, particularly involving inhibitory optogenetic tools, often require prolonged illumination of neural tissue which may cause temperature changes. Numerous studies ensued, utilizing Channelrhodopsin-2 and other microbial rhodopsins in a variety of neural circuits and animal models. In neural circuits, connectivity and function are thought to be tightly linked. Neurons projecting to defined long-range targets have been shown to possess defined functional properties, and dissecting these roles has been a major application of optogenetic tools. Optogenetics is readily applicable to light-accessible preparations such as cultured neurons, brain slices, transparent organisms such as zebrafish larvae, or to the cortical surface of rodents, allowing for extensive flexibility in light delivery. Light needs to reach the target with sufficient irradiance to induce opsin activation in a sufficient number of neurons.