Annoucements & Updates
Coming soon:
Video clips demonstrating the performance of animals in our novel tests of learning, memory and anxiety. Our test are strongly validated, sensitivie, reliable and very cost-effective for the screening of behavioral phenotypes and CNS drugs
Differences between Balb/c, c57/BL6J and CD-1 mice exposed to an elevated platform with steep slopes
Open Space Anxiety
(Video Demonstrations)
Effects of Diazepam and Amphetamine on the behavior of Balb/c mice exposed to an elevated platform with steep slopes
Open Space Anxiety
(Video Demonstrations)
Differences between Balb/c, c57/BL6J, CD-1, CBA, DBA and C3H mice in the 3D Maze
Videos coming soon!
Effects of Diazepam and Chlordiazepoxide on the behavior of Balb/c, c57/BL6J and CD-1 mice exposed to a 3D maze
1) The object recognition and object location. These tests are performed in an open-field or on elevated platform. They can be performed in a single session constituted with two phases, the sample phase and the choice phase. Two identical objects are presented in the sample phase and after a delay of retention animals are re-exposed to two objects. In the choice phase of the object recognition task one of the two objects is novel whereas in the choice phase of the object location task, one of the two objects occupies a novel place. Animals spend more time exploring the novel object than the familiar one and they spent more time exploring the object in a novel location than the object in its familiar location (see Ennaceur 2010; Ennaceur et al. 2009).
2) The elevated platform which is the equivalent of the open field except that there are no walls and corners to escape to. This elevated platform is used to assess emotional responses to an unfamiliar open space and it is also used to assess object recognition. In a recent modification, we added steep slopes on two opposite sides of the platform. Animals are released from a marked central area and left to explore for 12 min. Animals with low anxiety cross onto the slopes while animals with high anxiety do not cross onto the slopes (see Michalikova et al. 2010; Ennaceur et al. 2010; Ennaceur et al. 2010).
3) The 3 D maze is a modification of the 8-arm radial maze. It consists of 8 arms radiating from a central platform. Each arm is made of two segments, a bridge and an end arm. These arms can be presented raised, lowered or flat. This maze can be used in mice and rats for assessing emotional responses to novelty and open spaces following first sessions of exposure to the apparatus and it can be used for assessing spatial navigation and working memory in subsequent sessions (see Ennaceur et al. 2008; Ennaceur et al. 2006; Ennaceur et al. 2008).
4) In spatial mazes animals are introduced to a a learning and memory test with the implicit assumption that pre-training habituation sessions are sufficient to equalize the level of emotionality between groups. However, the number of these sessions is defined a-priori and varies widely between laboratories. There are no measures in place to assess whether and when such emotional responses did indeed subside before the start of the behavioral training, whether an experimental manipulation (genetic, drugs or lesions) would have not interfered with the habituation process and, that the natural tendency of animals to alternate between arms have not already set into place a cognitive map of the maze and initiated a working memory process during these successive pre-training sessions. Hence, it is worthwhile to introduce animals to spatial mazes without prior habituation. Depending on the strains of mice and the treatment application, one can assess whether the duration of the anxiety state is either shortened or prolonged, and whether this would account for learning and memory performance (see Ennaceur 2011; Ennaceur et al. 2011).
We are currently investigating the underlying physiological, neuroanatomical and molecular bases of fear and anxiety in the above models. We are also using these models to examine differences between strains of rats and mice in cognition and emotion.
We use numerous techniques including brain stimulation and lesions, anatomical tracing, administration of drugs, and detection of proteins and messenger RNA using in situ hybridization, immunohistochemistry, Northern and Western blotting.
Recent publications:
