The DanioVision Toplight Unit is an add-on for DanioVision that provides a ceiling light - lighting above the well-plate or arena that does not obscure the view of the camera. For multifunctional purpose, both sides of the Toplight Unit are covered with LED lights; one side consists of white LEDs, while the other contains red, green and blue LEDs.
Light from above
The DanioVision Observation Chamber already includes a light source from beneath, which provides IR-light for optimal tracking of larvae, and a white light to use as a stimulus (at over 30,000lux this light is perfectly suited to elicit a startle response). However, some studies (e.g. on photobiology*) require the more ‘natural position’ of light: from above. Also, certain affected fish may experience conflict from their innate orientation systems (photoreceptors, lateral line, vestibular system) when exposed to light from beneath. Other species such as aquatic worms, have ventral photoreceptors and can flip and swim upside down when presented with light from below, further indicating the need for a top-down light system.
Different colors in DanioVision
With the Toplight Unit, you can easily incorporate color stimulation into your experiments. You can pick the colors that fit the aim of your study, and the behavior and zebrafish strain of interest. The Max. F. Perutz Laboratories/University of Vienna (Austria) use different wavelengths to stimulate groups of photoreceptors that have response peaks specific to certain wavelengths. Using light of a particular color helps narrow down the number of receptors that respond, in order to focus on the relevant ones.
Zebrafish see color
Recent studies have shown that zebrafish are able to discriminate between different wavelengths of light; in other words, they see color. For example, chapter 6 of Farooq’s dissertation proved this using zebrafish larvae in a color-enriched open field assay. His larvae showed a preference for orange and green, and avoided yellow, blue, red, and black.
Zebrafish are influenced by color
A range of studies indicate that light conditions also influence the development, growth, and survival of zebrafish; the degree of effect depends on the wavelength (color) of the light. Villamizar et al. found that hatching rate was higher under blue and violet light, and the total length of the zebrafish at 30 days after hatching was greatest when raised under blue, violet, and white light. Contrary, red light exposure led to less feeding and poor survival rates.
Using colors in experiments
So zebrafish see colors and are influenced differently by different wavelengths. This opens up opportunities to test learning, memory, anxiety, and more. Research in this area has already begun; Li et al. that showed that zebrafish (repeatedly exposed to alcohol) display distinct learning and memory abilities in color-enhanced conditional place preference tests.
Combine different stimuli
Several add-on stimuli are available for DanioVision, including the Tapping Device. Located at the bottom of the chamber, this instrument allows you to induce vibrations in the water to elicit a startle response. You can combine this with light stimuli in your testing protocol. All are easily programmed and controlled based on timing or animal behavior with EthoVision XT.
*Information kindly provided by Kristin Tessmar-Raible from the Max. F. Perutz Laboratories/ University of Vienna, Research Platform Rhythms of Life, Vienna Biocenter, Austria.
- Ahmad, F. (2014) Zebrafish embryos and larvae as a complementary model for behavioural research. Integrative Zoology, Institute of Biology (IBL), Faculty of Science, Leiden University
- Villamizar, N.; Vera, L.M.; Foulkes, N.S.; Sánchez-Vázquez, F.J. (2014) Effect of Lighting Conditions on Zebrafish Growth and Development. Zebrafish, 11(2), 173–181.
- Li, X.; Li, X, Li, Y.-X.; Zhang, Y.; Chen, D.; Sun, M.-Z.; Zhao, X.; Chen, D.-Y.; Feng, X.-Z. (2015) The Difference between Anxiolytic and Anxiogenic Effects Induced by Acute and Chronic Alcohol Exposure and Changes in Associative Learning and Memory Based on Color Preference and the Cause of Parkinson-Like Behaviors in Zebrafish. PLOS ONE, e0141134
If you are interested in incorporating the Toplight Unit with white and colored LED lights into your DanioVision experiment, or if you are interested in a complete DanioVision set-up, please do not hesitate to contact your local sales representative!
Are you interested in using optogenetics in your DanioVision study? We also have a specific add-on for that!