Can Automated Analysis Improve the Marble Burying Test for Mouse Behavior?

What you need to know

• The researchers developed a new automated method to analyze mouse behavior in the marble burying test, which is often used to study anxiety and repetitive behaviors.
• The automated method provides more detailed information about burying behavior than traditional manual scoring methods.
• Results showed that burying behavior is distinct from general activity levels and repetitive behaviors seen in some mouse models of neurological disorders.

Background on the marble burying test

The marble burying test is a common behavioral experiment used with mice to study anxiety-like behaviors and repetitive tendencies. In this test, researchers place a mouse in a cage with marbles partially buried in bedding material. They then observe how many marbles the mouse buries over a set period of time.

Traditionally, experimenters manually count the number of buried marbles at the end of the test. However, this method has some limitations:

1. It only provides information about the end result, not the mouse’s behavior throughout the test.
2. There can be inconsistencies between different experimenters in how they count buried marbles.
3. It doesn’t capture details about the mouse’s movements or specific burying actions.

A new automated approach

To address these limitations, the researchers developed an automated method to analyze mouse behavior during the marble burying test. This method uses video recordings and computer software to track the mouse’s movements and identify burying behaviors.

The key components of this new approach are:

1. Video recording of the entire test session
2. Computer tracking of the mouse’s position and movements
3. A machine learning algorithm trained to detect burying behaviors
4. Analysis of various behavioral characteristics like number of burying bouts, duration of burying, and movement patterns

This automated method provides much more detailed information than simply counting buried marbles at the end of the test.

Testing the new method

The researchers tested their automated analysis method using several different types of mice:

1. Normal “wild-type” mice
2. Mice with a genetic mutation that causes Angelman syndrome (a neurodevelopmental disorder)
3. Mice with a mutation linked to autism spectrum disorders
4. Mice with a mutation associated with obsessive-compulsive disorder (OCD)

They compared the results from their automated method to traditional manual scoring. They also looked at how the different mouse types behaved in the marble burying test.

Key findings

The automated analysis method revealed several important insights:

1. It accurately detected differences in burying behavior between normal mice and those with the Angelman syndrome mutation, consistent with previous research.

2. Mice with the autism-related mutation showed decreased burying behavior, even though they were more active overall. This suggests burying is not directly linked to general activity levels.

3. Mice with the OCD-related mutation did not show any differences in burying behavior compared to normal mice. This was somewhat surprising, as these mice typically show increased repetitive behaviors in other tests.

4. When the researchers gave a calming drug to the hyperactive autism-model mice, it reduced their activity but did not change their burying behavior. This further supports that burying is separate from overall activity.

5. The automated method provided information about where in the testing area mice preferred to bury marbles, revealing differences between mouse types that weren’t apparent from manual scoring.

Conclusions

• The new automated analysis method provides a more detailed and consistent way to measure mouse behavior in the marble burying test compared to traditional manual scoring.

• Burying behavior appears to be distinct from general activity levels and other types of repetitive behaviors seen in mouse models of neurological disorders.

• The marble burying test may be measuring a unique aspect of mouse behavior that is not fully captured by other common behavioral tests for anxiety or repetitive tendencies.

• Further research is needed to understand exactly what types of mouse behaviors the marble burying test is measuring and how they relate to human conditions.

This automated approach opens up new possibilities for using the marble burying test to study mouse behavior and test potential treatments for neurological disorders. By providing more detailed behavioral information, it may help researchers better understand the complex relationships between genes, brain function, and behavior.