The open field test is an experimental method commonly used in behavioral neuroscience to assess anxious behavior, exploratory behavior, and motor activity in mice or rats. This type of experiment involves placing the animal in an open, usually square or circular space, to observe how it behaves for a certain period of time. Open-field experiments are simple in design but provide a wealth of information about animal behavior and are important tools for studying neurobehavior and pharmacology.
In open field experiments, researchers typically observe and record the animal's behavior, including its movement path within the field, the length of time spent in the center and edge of the field, and the behavior of standing up and cleaning itself. Longer periods of time spent in the central region are often interpreted as exhibiting lower levels of anxiety, while longer periods of time in the marginal region (known as "wall-edge behavior") may exhibit higher levels of anxiety. In addition, the total distance and speed of the animal can also be used as indicators to assess its activity level and exploratory behavior.
Open field experiments are widely used in neuroscience research. It can be used to assess the effects of drugs on animal behavior, particularly the effects of anxiolytic and antidepressant medications. In addition, by comparing the performance of different genotypes or populations of animals that have undergone specific treatments in open-field experiments, researchers can ** how specific genes or biological processes affect animal behavior. For example, when studying animal models of Alzheimer's disease, open-field experiments can help scientists understand the impact of the disease on an animal's ability to explore and move.
Experimental setup
Multichannel mouse open field experiment, XR-XZ301-M, Shanghai Xinsoft
The Open Field Experimental Apparatus is a fundamental tool for behavioral neuroscience research, with a simple but powerful design. This device is primarily used to assess anxious behavior, exploratory behavior, and locomotor activity in laboratory animals such as rats or mice. At the heart of the installation is an open, space-confined box, usually square or round.
For rats, the apparatus for open field experiments usually has a larger size, such as 100 cm x 100 cm x 40 cm (L x W x H). This size is large enough to allow the rat to move freely inside and explore the environment without feeling too cramped. For mice, the open field setup is relatively small, with a common size of 50 cm x 50 cm x 40 cm. Despite its small size, this size is still sufficient for mice to move and explore naturally.
The height of the open field experimental apparatus (40 cm) is appropriate for both rats and mice, sufficient to prevent them from jumping out of the box. The box is usually made of a transparent or translucent material, such as acrylic or glass, so that researchers can clearly observe the animal's behavior. The floor of an open-field experiment may be divided into a number of small squares to facilitate the recording and analysis of the animal's movement paths and behavior patterns.
In addition, open-field experimental setups may be equipped with advanced monitoring equipment, such as cameras and motion tracking software, to automatically record and analyze animal behavior. The application of these technologies has greatly improved the efficiency and accuracy of data collection while reducing human error.
Experimental setup: As previously described, the size of the open field device used in rats is typically 100 cm x 100 cm x 40 cm, while that of mice is 50 cm x 50 cm x 40 cm.
Environmental conditions: The laboratory should be kept silent and the light conditions should be controlled at a moderate level to reduce the influence of external factors on animal behavior.
Acclimatization: Before the experiment, animals should acclimatize to a laboratory environment for at least 30 minutes to reduce the stress response to the new environment.
Placement of the animal: At the beginning of the experiment, gently place the animal in the ** or one corner of the open field apparatus.
Behavioral observation: Start recording the behavior of the animal in the open field. The observation time is usually 5 to 10 minutes, which is the standard length in most studies.
Behavioral indicators: Record the animal's behavior, including time spent in the center and edge of the open field, distance moved, cleaning behavior, standing behavior, etc.
Data Recording: Record and analyze animal behavior using cameras and motion tracking software to improve the accuracy and objectivity of data.
Animal recap: At the end of the experiment, the animal is safely returned to its cage.
Cleaning and disinfection: Clean and disinfect open field devices to avoid cross-contamination.
Behavior analysis: Based on the data of video recording and motion tracking software, analyze the behavior patterns of animals, including movement tracks, stay areas, etc.
Statistical Processing: Analyze data using appropriate statistical methods in order to draw scientific conclusions.
Ensure that the open field device is cleaned and disinfected before and after use by each laboratory animal.
Observation and documentation should be done with minimal human intervention so as not to affect the natural behavior of the animal.
Experiments should be performed under the same environmental conditions to ensure comparability of data.
References
hall, c. s. (1934). emotional beh**ior in the rat. i. defecation and urination as measures of individual differences in emotionality. journal of comparative psychology, 18(3), 385.
This article was written by Cs.Hall, an early classic of open field experiments, mainly introduces how to use open field experiments to measure the emotional response of rats.
walsh, r. n., cummins, r. a. (1976). the open-field test: a critical review. psychological bulletin, 83(3), 482.
This review article provides an in-depth analysis and review of the open field experiment, and highlights its application and limitations in behavioral research.
prut, l., belzung, c. (2003). the open field as a paradigm to measure the effects of drugs on anxiety-like beh**iors: a review. european journal of pharmacology, 463(1-3), 3-33.
This review article focuses on the use of open-field experiments in pharmacological research, particularly for measuring the effects of medications on anxious behavior.
seibenhener, m. l., wooten, m. c. (2015). use of the open field maze to measure locomotor and anxiety-like beh**ior in mice. journal of visualized experiments, (96), e52434.
This article provides a detailed approach to using the open field assay to measure locomotor and anxiety-like behavior in mice.
gould, t. d., dao, d. t., kovacsics, c. e. (2009). the open field test. in mood and anxiety related phenotypes in mice (pp. 1-20). humana press.
The chapters of this book detail the application of open-field experiments in the study of mood and anxiety-related phenotypes in mice.