The hole-board test (HBT) is an experimental method used in scientific research to measure

anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...

stress Stress may refer to: Science and medicine * Stress (biology), an organism's response to a stressor such as an environmental condition * Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...

neophilia Neophile or Neophiliac, a term popularised by cult writer Robert Anton Wilson, is a personality type characterized by a strong affinity for novelty. The term was used earlier by Christopher Booker in his book The Neophiliacs (1969), and by J. D. ...

and emotionality in animals. Because of its ability to measure multiple behaviors it is a popular test in behavioral pharmacology, but the results are controversial.

Concept

The HBT was designed in the 1970s to mitigate the flaws of the open field test (OFT), another animal model that measures anxiety and exploratory behavior. Exploratory behavior requires a choice to be made to explore, but since the OFT is just simply a brightly lit area, the animal doesn’t have a choice. The OFT also doesn’t differentiate between locomotion and exploration. The HBT apparatus is an area with walls around it to prevent escape. The floor of the area is covered with holes. Over the years the HBT apparatus has become more complex. Modern devices are now monitored by computer and have infrared beams. The three common activities are head dipping, rearing, and

locomotion Locomotion means the act or ability of something to transport or move itself from place to place. Locomotion may refer to: Motion * Motion (physics) * Robot locomotion, of man-made devices By environment * Aquatic locomotion * Flight * Locomo ...

. Head dipping is commonly defined as when the animal puts his head into the hole until its ears are level with the floor or in modern devices when it breaks the infrared beam. Rearing is when the animal stands on its hind legs. Locomotion is the animal moving to a different area with all four paws. If the animal moves into the central area it is as separate observation because the central area is the most threatening to animals. These three behaviors are exploratory and the more they occur, the less anxious the animal is. On the other hand, if the animal doesn’t show these behaviors, then it is more anxious.

Scientific procedure

The procedure of this experiment can be modified depending on the behavior being measured. To examine anxiety a single animal is placed in the apparatus for five minutes where it is observed and then removed. Another animal that has been injected with an anxiolytic agent is then placed in the apparatus and then observed. Increased dose of anxiolytics leads to

sedation Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure. Examples of drugs which can be used for sedation include isoflurane, diethyl ether, ...

. To observe

and learning behavior, the test is typically done multiple times. As the tests go on, the number of head dipping decreases because the animal has now gotten used to the arena. These tests can also have objects in the area to promote exploratory behaviors. Animals in areas with objects showed increased locomotion compared to animals in arenas without objects.

Controversy

Since the root cause of anxiety is

idiopathic An idiopathic disease is any disease with an unknown cause or mechanism of apparent wikt:spontaneous, spontaneous origin. From Ancient Greek, Greek ἴδιος ''idios'' "one's own" and πάθος ''pathos'' "suffering", ''idiopathy'' means approxi ...

, animal models are difficult to create and therefore flawed. But because changes are seen through administration of anxiolytic agents, they are pharmacologically proven. In the HBT studies show inconsistent results when administrating known anti-anxiety medication such as

benzodiazepine Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, ...

s. The HBT showing neophilia is also controversial. Since animals show decreased head dipping, scientists conclude that it is a result of the animal becoming less fearful. However other studies have shown that after the amount of time with decreased head dipping, head dipping actually starts to increase, meaning that animals might have gotten bored with the area and are now exploring the holes.

References

{{Reflist Behavioral neuroscience Animal testing techniques

Concept

Scientific procedure

Controversy

See also

References