For analysis, data was averaged per day. After the probe trial, mice were given visible platform training to ensure that no gross sensorimotor or visual deficits were present. During the visible platform training, the platform was marked with a black-and-white ping-pong ball attached to a 10-cm wooden stick. No mice were excluded based on our standard

exclusion criteria in this task: Inhibitors,research,lifescience,medical excessive thigmotaxis, obvious visual impairment, excessive corkscrew swimming pattern, and obvious sensorimotor dysfunction. The water was frequently changed and the tank disinfected. Twelve control mice and 11 Thy1-hAPPLond/Swe+ mice were used. DMP dry maze The DMP water maze was originally designed to assess spatial working/episodic-like learning and memory in rats by Steele and Morris Inhibitors,research,lifescience,medical (Steele and Morris 1999). We designed a DMP dry maze test based on this DMP protocol, but excluding the water and swimming factors. The DMP dry maze is thought to measure similar learning abilities as the DMP water maze.

It was conducted using a novel, modified Barnes maze (dry maze) apparatus (Barnes 1979). The apparatus consists of a 122-cm diameter circular platform with 40 escape holes, Inhibitors,research,lifescience,medical each with a diameter of 5 cm placed along three rings of varying distances from the center of the platform. The outer ring has 16 holes and 50 cm from the center, middle ring has 16 holes and 35 cm from the center, and the inner ring has eight holes and 20 cm from the center. An escape box was attached to one of these holes and all holes were left uncovered.

High overhead lighting (1200 lux) and noise (2 KHz, 85 dB) were used Inhibitors,research,lifescience,medical to create aversive conditions that would encourage the mice to seek out the target hole to escape the light and noise. Visual cues Inhibitors,research,lifescience,medical were placed on all four sides of the maze. Mice were given a series of four trials with ITIs of 10 min; the maximum duration of each trial was 90 sec. For each trial, mice were placed in different locations at the edge of the maze and held under a dark cover to prevent a directional bias. After 10 sec, the cover was removed and the trial started. The distance from the releasing point and the escape box was generally the same within a day. The trial ended if a mouse found and entered the escape box before the end of the 90 sec. Mice that could not find the escape MTMR9 box were led to it by the experimenter and allowed to enter. As soon as the mouse entered the escape hole, the noise was turned off. After entering the box, the mouse was given 10 sec to see more remain in it before being returned to its home cage. The experiment was run for four consecutive days for the scopolamine experiment, and five consecutive days for the mutant mice experiment. On days 2–5, the location of the target escape hole was moved while all other parameters remained unchanged. All data was recorded using Ethovision. Parameters measured were escape latency, distance moved, and velocity.