Zebrafish larvae are transparent, which offers many benefits for neuroscientific research. One is the ease of applying optogenetic stimulation – there is no need for fiber optic implants.
Optogenetics and zebrafish larvae
In the last decade, a method was invented to specifically activate or even inhibit small groups of neurons with light: optogenetics. Today, scientists can insert light-sensitive receptor proteins into neurons in vivo, making these neurons sensitive to activation by light of specific wavelengths. This allows scientists to control the activity of these neurons and study their downstream influence on a variety of biological processes, including behavior. For rodents this requires the implantation of optical fibers, but since zebrafish larvae are transparent, light simply needs to shine in the right direction. This way the role of specific neurons in behavior can be examined and great progress can be made in the deciphering of the brain’s wiring.
DanioVision Optogenetics Add-on
There is an increase in the application of optogenetics in the field of zebrafish neurobiology, which motivated us to develop a specific add-on for DanioVision. Now researchers can easily functionally test the role of certain neurons in zebrafish larvae. The Optogenetics Add-on for DanioVision is an optogenetic LED light source (based on Prizmatix Modular LED system) that can easily be installed in your existing or new DanioVision Observation Chamber.
The standard DanioVision Observation Chamber can include an Optogenetics Add-on with two different wavelength (colors) LEDs. These can be used separately and simultaneously. Optionally, a custom Observation Chamber can include up to three LED colors.
Programming and control
DanioVision is powered by EthoVision XT video tracking software that allows for the control and programming of hardware. This means that you can set user-defined time conditions for the optogenetic stimulation. In comparison to manual control, this offers far better temporal precision and adds efficiency to longitudinal studies.
Optogenetics is used to monitor specific neuronal activity as well as directly manipulate neurons. Two of the most used effectors to stimulate or inhibit neurons are channelrhodopsin-2 (ChR2) and halorhodopsin (NpHR).
For example, NpHR has successfully been used to inhibit swimming behavior in zebrafish larvae (Arrenberg, et al., 2009). Other research showed that ChR2 activation induced backward swimming in a sparse transgene expression line (Zhu et al., 2009).
- Arrenberg, A.B.; Del Bene, F.; Baier, H. (2009) Optical control of zebrafish behavior with halorhodopsin. Proceedings of the National Academy of Sciences of the United States of America, 106, 17968-17973.
- Del Bene, F.; Wyart, C. (2012). Optogenetics: A new enlightenment age for zebrafish neurobiology. Developmental Neurobiology, 72(3), 401-414.
- Portugues, R.; Severi, K.E.; Wyart, C.; Ahrens, M.B. (2013). Optogenetics in a transparent animal: circuit function in the larval zebrafish. Current Opinion in Neurobiology, 23(1), 119-126.
- Simmich, J.; Staykov, E.; Scott, E. (2012). Zebrafish as an appealing model for optogenetic studies. Progress in Brain Research, 196, 145-162.
- Wyart, C.; Del Bene, F. (2011). Let there be light: zebrafish neurobiology and the optogenetic revolution. Reviews in the Neurosciences, 22(1), 121-130.
- Zhu, P.; Narita, Y.; Bundschuh, S.T.; Fajardo, O.; Scharer, Y.P.; Chattopadhyaya, B.; Bouldoires, E.A.; Stepien, A.E.; Desseroth, K.; Arber, S.; Sprengel, R.; Rijli, F.M.; Friedrich, R.W. (2009) Optogenetic dissection of neuronal circuits in zebrafish using viral gene transfer and the Tet system. Frontiers in Neural Circuits, 3, 21.