Developed by Calvin S. Hall to test emotionality of rodents, the open field test (OFT) is a commonly used qualitative and quantitative measure of general locomotor activity and willingness to explore in rodents. However, the extent to which behavior in the open field correlates with general locomotor activity in other situations (e.g., in a home cage or on an activity wheel) is controversial.
The open field is an arena with walls to prevent escape used for testing. Commonly, the field is marked with a grid and square crossings. Rearing and time spent moving are used to assess the activity of the rodent. In the modern open field apparatus, infrared beams or video cameras with associated software can be used to automate the assessment process. The OFT is also often used to assess anxiety by including additional measures of defecation, time spent in the center of the field, and the first few minutes of activity. The relation between the OFT and other tests of exploratory activity (elevated plus maze and emergence) have been analyzed in two mouse strains. Changes in these measures are often used to assess the sedative or stimulant effects of pharmacological agents.
Newer attempts have been made to analyse the OFT by quantifying the animal's moment-by-moment developmental dynamics. A recent study was able to show that mouse exploratory behavior consists of sequences of repeated motion: iterative processes that increase in extent and complexity, whose presumed function is a systematic active management of input acquired during the exploration of a novel environment.
^Denenberg, Victor H. (July 1969). "Open-field Behavior in the Rat: What Does it Mean?". Annals of the New York Academy of Sciences159 (Experimental Approaches to the Study of Emotional Behavior): 852–859. doi:10.1111/j.1749-6632.1969.tb12983.x.
^Prut, L; Belzung C (2003). "The open field as a paradigm to measure the effects of drugs on anxiety-like behaviors: a review.". European Journal of Pharmacology463 (1-3): 3–33. doi:10.1016/S0014-2999(03)01272-X. PMID12600700.
^Lalonde, R; Strazielle C (2008). "Relations between open-field, elevated plus-maze, and emergence tests as displayed by C57/BL6J and BALB/c mice.". Journal of Neuroscience Methods171 (1): 48–52. doi:10.1016/j.jneumeth.2008.02.003. PMID18358538.