Diana, Vincent & Amelia

We investigated whether the behaviour of mice can be shaped such that two mice will nose-poke for a reward in a coordinated manner. To do so, we devised an automated cage setup where two mouse are housed in individual compartments of a divided cage. The training schedule was divided into four phases:

Phase 1. Mice were trained to nose-poke for a water reward. Here, an opaque divider was used to separate the mice.

Phase 2. Mice were trained to nose-poke only after a LED to the left of the poke turned on to initiate the trial. The LED-on time after a successful poke was randomized to prevent habituation to the trial start time (between 1 and 30 seconds). A second LED at the top of the poke was used to reinforce a successful poke.

Phase 3. Bonsai was used to track the movement of the mice in a specific zone. When both mice were in a designated zone around the nose-poke, the LED used to initiate the trail was activated for a random duration (between 1 and 60 seconds). The reinforcer LED followed a rewarded poke. The divider between the two mice was transparent to allow the animals to observe the behaviour of the other.

Phase 4. The duration of the LED-on was incrementally reduced with successful pokes. If animals successful completed greater than 75% of pokes they advanced to the next trial, while a performance of less than 35% accuracy lead to repetition of the previous trial. (Trial 1. 5 seconds, Trial 2. 3 seconds, Trial 3. randomized between 800 milliseconds and 1 second. Trial 4. 500 milliseconds)

All mice successfully learned that the LED demonstrated the availability of reward in Phase 1 and 2. In conditions where reward was restricted to the presence of both animals within a designated zone, mice that were simultaneously active in their poking behaviour appeared to make rewarded pokes around the same time. In the future, the water deprivation schedule of the animals, the apparent lack of salience that the indicator LED showed and an improved design of cages to better contain the animals are factors that should be taken into consideration.