Simplifying behavioural protocols for zebrafish

The Brain and Behaviour lab at University of Portsmouth, led by Dr Matt Parker, uses Zantiks units in its research into basic neural and behavioural biology of impulsive / compulsive disorders and the effects of drugs during early brain development on behaviour and cognition.

Part of the lab's approach involves establishing simplified behavioural protocols for zebrafish, many of which are based on established protocols used on other model organisms, such as mice.

Parker discusses in an interview with Neuroscience News and Research, how the Zantiks units have proven invaluable to his work, as they can be applied across species from zebrafish larvae and adult zebrafish to mice. With fully integrated stimuli, all members of his team are able to use the Zantiks units for a wide array of behavioural assays.

Parker explains:

One of the problems facing zebrafish researchers is finding equipment that allows you to do a variety of behavioural tests, whether they be conditioned or unconditioned. For example, if you want to do a 2-choice discrimination task where you are using food as a reinforcer, or if you wanted to do a shock avoidance task where you are delivering a brief mild electric shock contingent on a particular conditioned stimulus, those kinds of protocols were very difficult with the equipment that was available. The Zantiks equipment has been a real godsend because they have developed a fully integrated testing environment that allows us to test pretty much every aspect of zebrafish behaviour. The equipment also allows us to study zebrafish behaviour in a very controlled environment. It is also transferable between animals, so you could use the same equipment to test mice.”

Much of the current work involving conditioning protocols with zebrafish requires single housing of the animals for long periods of time. Keen to reduce the need to house fish singly, Parker sought out protocols, using the Zantiks kit, that provide data quickly. For example, the lab is conducting Pavlovian fear conditioning and has recently developed a zebrafish Y-maze protocol. Y-maze spontaneous alternation procedures have long been used with rodents. In the basic procedure, an animal is placed in a ‘Y’ shaped environment and every time they enter one of the arms, they have two choices: they can either go to the left or they can go to the right.

Developing this protocol for use with zebrafish, Parker has collected data, over varying time frames, building up to a point of recording 100 choices per fish. Being able to quickly run the procedure such a large number of times in the Zantiks units, across various pharmacological treatments and ages of fish, facilitated reliable and replicable results.

It was found that the performance of the fish could be reliably categorised into overlapping series of four choices (e.g., RRRR RRRL RRLL through to LLLL), which created 16 potentials sets of choices. Therefore, the fish do not randomly search, but tend to show more alternation (e.g., LRLR RLRL) throughout the procedure. Parker used this finding as a behavioural outcome to test a number of different drugs. Differences in choices in the Y-maze were also found to be dependent on the drug treatment, the age of fish and early life stress. Dr Parker clarified,

There seem to be some pharmacological conditions that seem to increase their repetitions. At the moment we are exploring Y-maze as a potential lens into a variety of different cognitive problems that we might want to address.”

Matt Parker summarised the practical impact the Zantiks systems has had on his research:

In previous situations, for example with Pavlovian studies, I would have had to run one fish at a time over a relatively long period, and might, if lucky, get thorough 10 fish a day. Now I’m in a position where I can run four fish at a time per tank, so with 4 tanks I can run 16 fish at a time with 4 units, and 100 fish in a day. In a lab like mine that is busy, a lot of people working on different projects, the Zantiks kit is fantastic as it allows us to increase our throughput beyond any previous level we were ever even able to dream of."

For the full video interview conducted by Technology Networks science writer, Adam Tozer, on Neuroscience News and Research, click here.