Mice housed in a cage with a maze learn the maze without explicit training.
Mice were housed in a cage with a maze. A water tap was placed at the entrance of the maze. The exit of the maze connected with another cage (home cage). Food was placed in the home cage. Three different multiple mazes (types 1-3) were placed. 1) Mice were housed for 10 h a day in the apparatus and then removed to a normal cage for fasting. One trial per day was carried out after fasting for 13 h. In each trial, a mouse was put at the entrance of the maze and then the number of errors and the time till it reached the home cage was counted. Mice reached a learning criterion at Trial 2. 2) Administering scopolamine (0.125-0.5 mg/kg) 30 min before Trial four disturbed the maze work dose dependently in a type 3 maze, the most complex maze among the three, but did not in type 1 and 2 mazes. 3) Administering scopolamine (0.25-1.0 mg/kg) 30 min before Trial 11 to the mouse of the type 3 maze did not disturb the maze work. These results show that a mouse housed in a cage with a maze learns the maze without explicit training and scopolamine can differentially effect performance based upon the degree of training.