2.2.1 Novel Object Recognition Test (NORT)
A modification of NORT protocol was performed (Ennaceur and Delacour,
1988). In brief, mice were placed in a 90° two-arm (25 x 20 x 5 cm)
black maze, with removable walls for easy cleaning and light intensity
in mid-field was 30 lux. Before the memory, trials mice were habituated
to the apparatus for 10 min for 3 days. On day 4, the animals were
submitted to a 10 min acquisition trial, in which they were allowed to
freely explore two identical objects located at the end of each arm
(First trial-Familiarization). After 2h (for short-term memory
evaluation) and 24h (for long-term memory evaluation) from the first
trial, the mice were submitted to a 10 min retention trial, in which one
of the two identical objects had been replaced by a novel one. The
behaviour was recorded, and the time spent that the mice spent exploring
the new object (TN) and the old one (TO) were measured manually.
Exploration was defined as sniffing or touching the objects with nose
and/or forepaws. The discrimination index (DI) was calculated as
(TN-TO)/(TN+TO). To avoid object preference biases, objects were
alternated. 70% EtOH was used to clean the arms and objects after each
trial for the elimination of olfactory cues.