The elevated plus maze is one of the most used behavioral tests for anxiety. The maze consists of two open arms and two closed arms. The test relies upon the animal’s natural tendency to stay in enclosed spaces and fear of open spaces and heights. In general, animals spend more time in the closed arms and less time on the open arms. Anti-anxiety medications increase time spent on the open arms. The UH ABC offers Elevated Plus Maze for both mice and rats. Digital videos of the animal’s behavior is analyzed using EthoVision XT 12.0.
The open field test is to assess locomotor activity, anxiety-related and exploratory behavior of rodents. The open field consists of a square test arena, in which the animal’s activity is recorded with high-end digital cameras. The amount of time spent close to the wall, time spent and number of entries into the center zone are key measurements. Anxious animals spend more time around the perimeter (thigmotaxis) whereas animals that are not anxious spend more time in the center zone of the test arena. Anxiolytics increase time spent in the center zone. Other behaviors taken into consideration include distance traveled, velocity, freezing, and stretch-attend postures. Digital videos of the animal’s behavior is analyzed using EthoVision XT 12.0 Body Recognition module.
The (Porsolt) forced swim test, also known as the behavioral despair test, is used to test for depression-like behavior in both mice and rats. The test includes placing an animal inside a cylinder filled with water. The mobility and immobility of the animal is measured. Traditionally, “floating behavior” (the animal remains almost immobile and with its head above water) is used as a parameter to analyze “hopelessness” and thus depression-like behavior. Behavior can be measured manually or digital videos of the animal’s behavior can be analyzed using EthoVision XT 12.0.
Locomotor sensitization is a commonly used behavioral model of addictive disorders in rodents whereby drug is administered over consecutive days or alternating days and locomotor activity and other behavioral measures recorded. Stimulants increase locomotor activity over consecutive days when administered the same drug dose which is called sensitization, a rudimentary animal model of addiction in humans. Unpurposeful, repeated movements called stereotypy may also be associated with drug sensitization. All substances linked to addictive disorders in humans affect locomotor activity at appropriate doses. Other behaviors taken into consideration include distance traveled, velocity, freezing, and stretch-attend postures. Digital videos of the animals behavior is analyzed using EthoVision XT 12.0 Body Recognition module.
Learning and Memory
The Morris Water Maze (MWM) is a popular behavioral assay for assessing spatial learning and memory. The water maze consists of a pool, with a hidden platform submerged just below the surface of the water. Animals undergo training sessions over days whereby they are given the opportunity to locate the platform using cues. Some genetically engineered mouse strains that model cognitive impairment in humans show impaired special learning. Medications that increase central acetylcholine levels improve performance in the MWM whereas those that block cholinergic receptors decrease performance. In general, this behavioral assay is broadly hippocampal-dependent. The UH ABC offers MWM for both mice and rats. Data is generated by analyzing digital videos of the animal’s behavior using EthoVision XT 12.0.
The radial arm maze is a paradigm that is used to assess spatial, working and reference memory in rats and mice. When investigating working memory, all arms are usually provided with a (food) reward and the animal should visit each arm only once. When used for assessing reference memory, only some of the arms contain a reward and the animal should only visit those baited arms. Visits to an arm more than once or visits to non-baited arms count as working memory errors or reference memory errors, respectively. Similar to the Morris Water Maze, special learning and memory in the radial arm maze is broadly hippocampal-dependent. The UH ABC offers radial arm mazes for both mice and rats. Data is generated by analyzing digital videos of the animal’s behavior using EthoVision XT 12.0.
Pavlovian or classical fear conditioning is produced when an innocuous conditioned stimulus (CS) is paired with an aversive unconditioned stimulus (US) that then elicits an unconditioned fear response. By way of CS-US pairings the CS eventually generates a conditioned response (CR) that resembles an innate fear reaction. In rodents, freezing is the innate fear response and is the primary measure assessed in fear conditioning although others have been used (e.g. ultrasonic vocalizations, changes in the autonomic nervous system).
Fear conditioning is typically done by using a tone, light or context as the CS and a mild electric foot shock as the US. Fear learning and memory is quickly established and is robust. This type of conditioning is heavily dependent upon the amygdala. The UH ABC offers 4 state of the art fear conditioning chambers for both mice and rats. Data is generated by analyzing digital videos of the animal’s behavior using EthoVision XT 12.0.
Novel object recognition is a highly validated test for recognition memory. This behavioral assay can be used in a number of ways for example, to test compounds that affect memory, the contribution of genes in genetically modified mice or the impact of age on memory. There are numerous variations of this test however it is typically carried out using one habituation session and a familiarization session and test session divided by an intersessional interval. The animals are first habituated to the test arena without objects. The animal is then allowed to explore the arena containing two identical objects (familiarization session). For the test session, one of the objects is replaced by a novel object. The advantage of this test is that it relies on the ethologically innate tendency of a rodent to explore an unfamiliar object. Time spent exploring the novel object is an important measure of this test. The UH ABC offers 8 arenas for both mice and rats that can be used to conduct novel object recognition tests. Digital videos of the animal’s behavior is analyzed using EthoVision XT 12.0.
The study of social interaction can be done in a variety of set-ups, all having one thing in common: the study of behaviors between two or more animals. Behaviors of interest could be sexual and mating behavior, agonistic behavior, maternal behavior, etc. Often differences between treatment groups or genetic strains are investigated. Most tests are straightforward and conducted in an open field or home cage environment.
The rotarod test is a standard test to assess motor coordination and balance in rodents. The test measures an animal's ability to maintain itself on a rod that turns at a set speed or accelerating speeds. Latency to fall off the rotarod is the primary measure of this behavioral assay. The UH ABC offers a rotarod apparatus for both mice and rats.
The tail flick test is used to measure pain (nociception) thresholds to an infrared heat source on a rodent’s tail. The animal’s tail is placed over an infra-red heat source controlled by the experimenter, a timer automatically begins. When the animal feels pain it immediately flicks its tail away. A sensor detects this movement and stops the timer and switches off the infra-red heat source. Reaction time or latency to withdrawal the tail is the primary measure of this reflexive assay. The UH ABC offers equipment to conduct the tail flick assay for both rats and mice.
The hot plate test examines nociception in mice and rats and complements the tail flick test. The rodent is placed onto a hotplate that delivers a controlled amount of heat stimulus. The latency to lick the hind paw is the primary measure of this reflexive assay. The UH ABC offers equipment to conduct the hotplate assay for both rats and mice.