Morris Water Maze

This is a test of spatial learning and memory. Animals are placed into a pool of water in which a platform is hidden beneath the surface. The animal must learn to use spatial cues located in the testing room to navigate to the platform. Longer latencies indicate poorer performance. Variants in the experimental protocol allow the experimenter to determine whether observed impairments are the result of working or reference memory systems.

Radial Arm Maze

This is another test of spatial memory. The maze consists of a central hub from which extend 8 different arms. Food is placed at the end of all (or some) arms, and the animal must learn to enter each arm a single time; errors are defined as repeat entries into already-visited arms. Although the simplest strategy to solve this task would be to enter adjacent arms, rodents do not typically adopt this tactic. As such, the analysis of arm entries can yield insight into such processes as planning and decision making and impulsivity in the rodent. The test can also be adapted to provide sensitive measures of working and reference memory. An additional advantage of the radial arm maze is that it avoids the stress of swimming imposed by the Water Maze. The disadvantage of the test is it requires food restriction, and entails considerably more training time to reach asymptotic levels of performance.

Object Recognition

This is a fast and quite efficient test to assess non-spatial working memory. The animal is first placed into an arena containing two identical, novel objects. After a predetermined period of exploration, the animal is removed, and a delay is imposed. Following the delay, the animal is placed back into the arena, where one of the objects is replaced by a novel object. Rodents typically avoid familiar objects and explore novel objects, so the amount of time investigating the novel object is taken as the measure of working memory (lower exploration of the novel object is interpreted as poorer working memory performance).

Olfactory Discrimination and Memory Test

The olfactory discrimination paradigm is a non-spatial learning and memory test specifically developed and validated for use in mice. In this test, one odour (e.g. lemon) is established as a CS+ for sugar delivery, whereas a second odor (e.g. rose) serves as a CS- for this reinforcer. Following training, preference for the sugar-paired odour (i.e., CS+) is assessed.

Barnes Maze

The Barnes maze is a rapid and efficient test that can be used to assess spatial reference memory in rats and mice. The Barnes maze consists of a bright, circular, exposed platform with small holes distributed throughout the circumference. A small, recessed chamber is located under one of the holes, into which the animal can escape. The animal uses spatial cues located in the room to identify the target hole. The primary dependent measures are the number of holes visited prior to finding the target hole, as well as the latency to escape. Although it is best suited to assessing reference memory, the test can be modified to assess working memory as well. The advantage of this test is that, unlike the Morris water maze and the radial arm maze tests of spatial memory function, it is presumed to be less stressful, and does not require food deprivation.

Fear Conditioning (Contextual and Cued)

Fear conditioning assesses the ability of an animal to associate a Conditioned Stimulus (neutral) with delivery of an Unconditioned Stimulus (aversive), usually foot-shock. Several dependent measures can be employed, although the most simple is to assess the degree of freezing that the CS elicits. The CS can be either contextual (the arena in which shock is administered), or it can be discrete (a light or tone cue that precedes the shock). Variations in the type of CS recruit neuroanatomically distinct systems; the hippocampus has been found to be crucial to supporting cued fear conditioning with a discrete CS, whereas the amygdale is essential to the acquisition and expression of contextual fear conditioning.

Spontaneous Alternation

This task exploits the innate tendency of rodents to avoid places already visited that are devoid of biologically significant stimuli (e.g. food, sexual partners). The benefits of such a foraging strategy are obvious. In this task, an animal is placed in the start arm of a T-maze, and is allowed to explore one of the two goal arms. Following a delay, the animal is returned to the maze and has free access to both of the goal arms. Alternation is recorded if the animal first chooses the alternate goal arm. This is considered to be a “spontaneous” choice as it is not reinforced. Increasing the delay between trials taxes the spatial working memory system.

Place Recognition (labyrinthe en T ou en Y)

Place recognition serves the same function as does the object recognition test, although in this paradigm the stimulus is a location, rather then an object. The test apparatus consists of a maze (either a T- or, more frequently, a Y-maze) in which each of the three arms is distinctively different. Animals are first confined to one or two arms of the maze, then, following a predetermined delay, are given free access to all three arms. The amount of time spent in the "novel" arm serves as the dependent measure.