Object recognition test in mice paper 2013

2014-12-08

Marianne Leger1,3, Anne Quiedeville1,3, Valentine Bouet1, Benoît Haelewyn2, Michel Boulouard1,  Pascale Schumann-Bard1 & Thomas Freret
France Nature protocols 2013 paper

The objects in their paper are about 8-cm high and 3.2-cm wide and 9.5 cm high, 2.5 cm deep, and 3.2 cm wide
They used legos and a tissue culture flask filled with sand.
-Note: 
--a orange 200 uL pipette tip box is 12.5 cm wide, 6.7 cm tall, and 9.9 cm deep
--tissue culture flask is 9 cm wide X 15.9 cm tall X 3.5 cm deep
--round container is 11.2 cm high and 9.3 cm diameter

--q
 a mouse is presented with two  
similar objects during the first session, and then one of the two objects is replaced by a new object during a second session.  
the amount of time taken to explore the new object provides an index of recognition memory.
--q
 with a short intersession interval  
(e.g., 6 h), this procedure can be performed in 4, 2 or 1 d, respectively, according to the duration of the habituation phase.
--q
the measure of the absolute time 
spent exploring each object during each session (a fixed duration 
of classically 3 or 5 min) 
--q
Access to novelty (e.g., an object or an environment) can elicit 
approach behaviors in rats.
--q
Thus, a rodent that remembers the familiar object will spend 
more time exploring the novel object.
--q
However, mice are not little rats and 
thus may neither behave in a similar way nor use similar strate-
gies
--q
 An additional variation is whether or not a habitu-
ation phase is performed. Some protocols preface the test phase 
with a habituation phase to the apparatus and to the procedure 
to reduce stress and to avoid a potential neophobic response
--q
the use of a 3-d habituation phase 
has been the most commonly used in mice
--q
It consists of expo-
sure to an open-field apparatus twice a day for 3 d before the test 
(3 min for each session). A shorter habituation phase, consisting 
of a single exposure to the apparatus, has also been proposed16,22 
but its usefulness remains a matter of debate. 
--q
For example, the maximal ISI duration for observ-
ing significant performances between different strains of mice 
was limited to 4 h in the protocol of Sik et al.20, whereas it was  
24 h for Frick and Gresack
--q
 the habit-
uation phase consists of two 5-min exposures to the apparatus per 
day separated by 6 h, during 3 d before the test phase 
--q
As rodents have difficulty in discriminating colors, the experi-menter should focus on the brightness and texture of the objects
--q
In the experiments reported here, we used common objects that 
differ in shape and texture; both of these objects can be climbed 
onto by mice, and both stand out against the background: towers 
of Lego bricks (8-cm high and 3.2-cm wide, built in white, blue, 
yellow, red and green bricks) and Falcon tissue culture flasks filled 
with sand (9.5 cm high, 2.5 cm deep and 5.5 cm wide, transparent 
plastic with a blue bottle cap)
--timing of the test
--q
mice were housed in a reversed light-dark cycle and were 
always tested in the dark phase (active phase between 08:00 and 
20:00). The familiarization session was always carried out during 
the morning (from 09:00).
--q
Here we chose to 
score object exploration whenever the mouse sniffed the object 
or touched the object while looking at it (i.e., when the distance 
between the nose and the object was less than 2 cm)
--q
Climbing 
onto the object (unless the mouse sniffs the object it has climbed 
on) or chewing the object does not qualify as exploration.
--q
 acknowledging that 
rodents explore primarily by sniffing, video-tracking systems based 
on nose-point detection are more reliable than packages based on 
the center point of the animal
--objects should be cleaned with ethanol
--they used reversed light-dark cycles for some reason
--q
 Adjust the luminosity of the room to obtain 15 lux in the center 
of the open field
--q
video camera placed above the arena.
--q
 The experi-
menter should be at least 1 m from the open field so that the mouse cannot 
see him or her directly
-- two identical objects in the open field, 5 cm away from the walls
--Start a stopwatch to measure the time 
necessary to reach the 20-s criterion of total exploration
-- Stop the experiment when there has been a 20-s exploration of both objects or when a 10-min period is over (i.e., the 
maximum session time).
--After the familiarization session, clean the objects and 
the open field with 70% (vol/vol) ethanol to minimize  
olfactory cues.

azim58wiki: