Stress and anxiety

As fish research increases in popularity, several paradigms used for rodents are translated into zebrafish studies, such as open field tests and light/dark boxes. One of the challenges in these studies though, is keeping track of these fast and sometimes erratically moving animals. EthoVision® XT is able to accurately detect and track fish of any species and provides you with the dependent variables you need in your research, such as distance moved, velocity, and time spend in the different parts of the tank. Combined with the Multiple Arenas Module, you can even track in multiple set-ups simultaneously, saving time and effort.  

 

Image Danio rerio courtesy of  Prof. Robert Gerlai, University of Toronto at Mississauga, Mississauga, Canada.

 

 

Examples of research

During a novel tank diving tests, behaviors such as bottom dwelling and latency to swim into the upper levels of the tank are important indicators of stress and anxiety, or the effect of anxiolytic or anxiogenic substances. Another example is the open field test, in which, similar to rodent studies, thigmotaxis can be investigated. Other paradigms include the light/dark box test and the predator avoidance test.

 

Examples of dependent variables:

  • Total distance travelled in bottom segment of novel tank.
  • Latency to enter upper segment.
  • Time spent in dark vs light chamber.
  • Time spent immobile
  • Mean turn angle

 

A few examples from publications that might interest you:

  • Ahmed, O.; Seguin, D.; Gerlai, R. (2011). An automated predator avoidance task in zebrafish. Behavioural Brain Research, 216, 166-171.
  • Bencan, Z.; Sledge, D.; Levin, E.D. (2009). Buspirone, chlordiazepoxide and diazepam effects in zebrafish model of anxiety. Pharmacology, Biochemistry and behavior, 94, 75-80.
  • Champagne, D.L.; Hoefnagels, C.C.M.; de Kloet, R.E.; Richardson, M.K. (2010). Translating rodent behavioral repertoire to zebrafish (Danio rerio): Relevance for stress research. Behavioural Brain Research, 214, 332-342.
  • Gerlai, R.; Fernandes, Y.; Pereira, T. (2009). Zebrafish (Danio rerio) responds to the animated image of a predator: Towards the development of an automated aversive task. Behavioural Brain Research, 201, 318-324.
  • Levin, E.D. (2011). Zebrafish assessment of cognitive improvement and anxiolysis: filling the gap between in vitro and rodent models for drug development. Reviews in the Neurosciences, 22(1), 75-84.

 

Behavioral indicators of stress and anxiety

Many researchers argue that anxiety and stress in fish are indicated by inhibited exploration, reduced speed, and more escape-like, erratic movements. All of these can be automatically detected and analyzed with EthoVision XT. 

 

Horizontal and vertical patterns of behavior

Zebrafish tend to show “bottom dwelling” in a novel environment, meaning that they dive to the bottom segment of a tank and dwell there in the first couple of minutes of a test. Then they gradually begin to explore the higher sections of the tank. Vertical swimming behaviors, as well as latency to enter the middle and upper segments of the tank are key variables in this research. EthoVision XT allows you to easily define the different tank segments, allowing for automatic comparison in swimming behavior (distance traveled, velocity, freezing bouts, angular velocity, etc.) between the different segments.

 

Other set-ups, such as the open field and light/dark boxes, monitor swimming behavior from above, inspecting horizontal swimming behavior by visually dividing the tank in inner and outer zones, and possibly in light and dark zones. Like rodents, zebrafish show thigmotaxis, staying close the walls when just entering a novel environment. However, in the light/dark box, zebrafish show a natural preference for lighter environments (which can be explained by the fact that they are diurnal), in contrast to rodents. Again, the position of the animal and the behaviors shown in different sections of the tank are easily investigated with EthoVision XT.

 

Compare manual observations
EthoVision XT has a built-in Manual Event Recorder. This equips you with an easy-to-use tool to score behaviors in addition to automatically recorded tracking data, or to validate and fine-tune automatically scored behaviors such as freezing or zigzagging. All your results are visualized and analyzed synchronously.