Elevated Plus Maze Model

Elevated plus maze model (EPM)
EPM is extensively used to study cognitive behavior of rodents. The Plus-maze apparatus consisting of two open and two covered (enclosed) arms, is based on the apparent natural aversion of rodents to open and high space (Ittoh et al., 1990). The apparatus had a central platform of 5 cm2 connected to two open arms (16 cm × 5 cm) and two closed arms (16 cm × 5 cm × 12 cm) in such a way that both open and closed arms are opposite to each other. The maze was elevated to a height of 25 cm from the ground. On day 7, 30 min after scopolamine administration, each mouse was gently placed at the distal end of an open arm, facing away from central platform. The time taken by the mouse to enter either of the closed arms with all four paws from open arm was recorded and designated as transfer latency time (TLT). If the mouse did not enter either of the closed arms within 90 s, it was gently pushed into one
The apparatus (Rolex, Ambala, India) consisted of a Plexiglas box (27 cm × 27 cm × 27 cm), a grid floor and a shock free zone (SFZ). The SFZ (wooden platform 10 cm × 7 cm × 1.7 cm) was at the centre of the grid floor. Electric shock (20 V AC) was delivered to the grid floor. Each mouse was trained to stay on the SFZ for at least 120 s on the 7th day of the treatment period. Each mouse was gently placed at SFZ and when the mouse stepped down with all the paws on grid floor, shocks were delivered for 15 s. The process was repeated several times until the animal learned to stay on the SFZ for at least 90 s. The retention was tested on the 8th day of the treatment period by placing again the animal on SFZ and then step down latency (SDL, time taken by mouse to step down with all four paws on the grid floor) was noted with an upper cuttoff time of 120 s. Increase in SDL indicates memory enhancing effect of drug (Singh and Goel,