What does the light-dark box test measure?

Answer: The light-dark box test is an animal behavioral test that measures anxiety.

In behavioral neuroscience, modeling human diseases and disorders is important. If we can develop an animal model for anxiety, for example, then we can test pharmacological compounds that change the behavior.

Anxiety is a remarkably common disorder among humans at approximately 15-20 percent depending on the estimate. It is characterized by an unpleasant internal state, which may be expressed in fearful responses to ordinary non-threatening stimuli.

In the light-dark box test (LDB), a rodent is placed into a box with two chambers connected by a narrow entranceway. One box is brightly lit and much larger. The other box is dark, and much smaller. The idea is that the rodent behavior is conflicted: The evolutionary protective ‘defensive’ brain wants to stay in the dark room, since they feel more protected from predators. The other part of the brain is curious, and wants to explore their novel environment, even the brightly lit area. The rodents do not any training to perform this task.

In a mouse or rat with anxiety like symptoms, they tend to avoid the brightly lit area. When given an anti anxiety drug (anxiolytic), they will move into the brightly lit area and spend more time exploring the area.

Criticisms of the light dark behavior box

The light dark box faces a few critiques. For example, the only anxiolytic drug that reliable produces results are the class of drugs called benzodiazepines, such as diazepam (Valium). Other drugs that decrease anxiety in humans may not have a significant impact on mice or rats in the light box test.

Another confounding variable arises from the way exploration is scored. Raising up on the hind legs is considered an exploratory behavior. Confusingly, drugs that increase locomotion also sometimes produce an increase in exploratory behavior, even if it has no effect on anxiety. This may result in a false positive.