Figure 1. Formalin test apparatus.

( a) Perspex acrylic glass arenas (36 x 40 x 13 cm), consisting of three mirrored and one transparent wall, were used for the formalin test. The recording camera was placed facing the arena, at an approximate 30° angle to the arena surface and 50 cm away from the transparent wall, so all mouse behaviour could be easily recorded for later analysis. ( b) Video still of an experiment, showing that the behaviour of the animal could be meticulously monitored and accessed.