open field test

Product Info

Open Field test is a popular protocol used to assess exploratory behavior and anxiety. Thigmotaxis in the open field is used to evaluate anxiolytic, anxiogenic and even non-pharmacological treatments. Ambulation is the most common behavior studied with this maze, but others such as latency or rearing can also be measured. In addition, objects can be added for a modification similar to the novel object recognition field.

  • Walls can be both opaque or clear. We recommend that clear walls are used for measurements of anxiety, while opaque walls are used if assessments include novel object recognition.
  • Walls are easily detachable for easy cleaning.
  • Grid floor insert available for video tracking

Request an Open Field

  1. Product Description
  2. Prices and Sizes
  3. Modifications Available
  4. Documentation
    4.1 Introduction
    4.2 Apparatus and Equipment
    4.3 Training Protocol
    4.4 Modifications
    4.5 Sample Data
    4.6 Strengths and Limitations
    4.7 Summary and Key Points
    4.8 References
  5. Product Blueprints
    5.1 Product Sizes
    5.2 Product Images

Prices and Sizes

Mouse

$ 490

+ Shipping and Handling (approx $100)

  • Removable base for easy clean
  • Acrylic
  • Easy clean with 70% Ethanol
  • Matte Finish for non shine
  • No odors

Rat

$ 590

+ Shipping and Handling (approx $150)

  • Removable base for easy clean
  • Acrylic
  • Easy clean with 70% Ethanol
  • Matte Finish for non shine
  • No odors

XS (Stroke)

$ 440

+ Shipping and Handling (approx $80)

  • Removable base for easy clean
  • Large singular box can serve as large Open Field
  • Separator included to divide into 4 individual mouse/rat boxes
  • Acrylic
  • Easy clean with 70% Ethanol
  • Matte Finish for non shine
  • No odors

Mouse (Set of 4)

$ 1790

+ Shipping and Handling (approx $300)

  • With wall insert

Rat (Set of 4)

$ 1890

+ Shipping and Handling (approx $400)

  • With wall insert

XS (Stroke - Set of 4)

$ 1590

+ Shipping and Handling (approx $150)

  • With wall insert

 Modifications Available

Grid Flooring w/ Cover

Used for Mouse, Rat or XS (Stroke)

Dimensions:
Mouse – 40x40cm to fit
Rat – 60x60cm to fit
XS (Stroke) – 25x25cm to fit

Cost $150

Floor Insert

Used for Mouse

Dimensions: 40x40cm

Cost $60

Floor Insert

 Used for Rat

Dimensions: 60x60cm

Cost $80

Documentation

Introduction

The Open Field test is based on the conflict between a rodent’s natural aversion to open areas and its willingness to explore new areas. It is used to measure anxiety states, as well as locomotor and exploration activity, in rodents. The Open Field test is commonly used alongside other mazes that measure anxiety, such as the Elevated Plus Maze, especially following treatment with anxiolytic and anxiogenic drugs (Schmitt & Hiemke 1997). The apparatus is very simple in design, and provides the animal with a novel area to explore. During a set time of exploration, the animal’s movement and behaviors are tracked. From these behaviors, information regarding the animal’s anxiety state can be deduced.

The task was originally designed in the 1930s by Calvin Hall, who used it to measure timidity in animals (Hall & Ballechey 1932). Since that time, it has been refined to measure more specific aspects of exploration, movement, and anxiety.

Apparatus and Equipment

A similar apparatus is utilized for both the Open Field and Novel Object Recognition tests. This consists of a square area surrounded by high walls. The size of the area can range from small (27×27 cm) to large (50×50 cm) and will depend on the species of animal to be tested. The walls are typically black, white, or clear, and are available in matte to prevent reflections. The apparatus may be placed on a table and does not require its own stand.

Floor inserts for the apparatus are available with or without gridlines. These gridlines divide the area into equal smaller squares and can be helpful for both manual scoring, as well as video recording and scoring with tracking software. A square area in the very center of the area may also be outlined.

The testing area should be sufficiently but dimly lit to allow animals to see and explore their surroundings while avoiding stress from bright lights.

A mounted video camera is used to record the experiments from above the open field. Tracking software can be used to follow the moments of the animals within the maze. Live scoring can also be performed.

Training Protocol

The purpose of the Open Field test is to measure exploration, locomotion, and anxiety. This test can be used to compare animals in a sham control group to animals in a treatment or disease model group by observing their behaviors and tracking their movements in the open field. The animals are exposed to a novel open area and given a certain amount of time to explore it. Animals with minimal anxiety are likely to move about the area and perform other behaviors such as grooming and rearing, while animals with increased anxiety may freeze or exhibit stretch attend postures. Different behaviors may be of interest and can be tracked depending on the treatment of the subject animals.

Evaluation of Locomotion, Exploration, and Anxiety Using the Open Field Test

Since this test measures exploration of the animal, there is no pre-training or pre-exposure necessary. To begin the trial, turn on the camera, and place the animal in the center of the open field apparatus. The animal is then allowed to freely move and explore for five minutes. After five minutes, the animal is returned to its home cage. Exposing animals to the apparatus for five minutes on two or more consecutive days will provide a measure of habituation to the novelty of the apparatus and area.

Behaviors of the animal exhibits during the test period can be tallied manually or by using tracking software. The number of times the animal crosses from one grid square to another with all four paws provides information about the animal’s locomotion activity. The number of times the animal enters the center square and how much time is spent there is also tallied. Other behaviors such as rearing, stretch attend postures, grooming, freezing, and urinating/defecating are also recorded and will provide information about the animal’s anxiety state and inclination to explore.

Modifications

The apparatus used for the Open Field test can easily be modified to work for the Novel Object Recognition test.

Simple modifications can be made to the time the animal is allowed to explore in the testing area or to the number of times the animal is repeatedly exposed to the testing area over several days. Different behaviors may also be measured and scored if necessary.

Sample Data

The data obtained from the Open Field test generally consists of times spent in different grid squares and a tally of behaviors of interest, such as crossing grid lines, rearing, grooming, etc. These measures can easily be displayed in a table, like the example shown below.

In addition to counting entries, a memory score can be calculated using the following formula:

Statistics such as averages and standard deviation can be easily calculated for these tallies. These measures can then be compared between a sham control group and a treated or mutant group. This will allow for easy visualization of effects on locomotor, exploratory, and anxiety behaviors. The specific treatment or mutation being tested will determine the differences in behavior between the control and subject groups. Generally, animal cohorts of approximately 30 animals are sufficient to obtain p-values of <0.05 using two-way factorial ANOVA and MANOVA followed by post hoc t-tests. (Schmitt & Hiemke 1998, Carola et al. 2002).

Strengths and Limitations

The Open Field test places minimal stress on the animals tested. The animals are simply asked to explore a new area; this does not require exposure to aversive stimuli, extensive pre-training, or food and water restriction. Prior handling, home cage isolation, and specific animal strain may affect observed behaviors and should be carefully considered when designing experiments (Schmitt & Hiemke 1998).

While the Open Field test provides a measure of locomotor activity, exploration activity, and anxiety-state all in one test, it is important to note that this test provides only an initial measure of anxiety. More specific mazes, such as the Barnes Maze, Elevated Plus Maze, and Zero Maze, should be used to gain additional information regarding the anxiety-state of animals.

Summary and Key Points

• The Open Field test is a commonly used task to measure locomotion, exploration activity, and anxiety
• This task exposes animals to a open field for a set time and records their movement and behaviors
• Animals in control groups show a willingness to explore, while animals treated with anxiogenic drugs, for example, show increased anxiety-related behaviors

References

Mouse

Open Field - Mouse (1)
Open Field - Mouse (2)

Mouse Open Field Size (CM)

  • Length: 40
  • Width: 40
  • Height: 30

Rat

Open Field - Rat (1)
Open Field - Rat (2)

Rat Open Field Size (CM)

  • Length: 60
  • Width: 60
  • Height: 40

XS (Stroke)

Open Field - XS Stroke (1)
Open Field - XS Stroke (2)

XS (Stroke) Open Field Size (CM)

  • Length: 25
  • Width: 25
  • Height: 25

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