Barnes Maze

The Barnes Maze is a behavioral task used primarily to assess spatial learning and memory in rodents. It is considered a dry-land alternative to the Morris Water Maze and is especially suitable for animals that are averse to swimming or for experiments where water-based stress needs to be minimized.

Protocoll

1. Preparation

   • Clean the maze and surrounding area.
   • Ensure the escape box is securely attached under the designated target hole.
   • Place distal visual cues on the walls of the testing room.
   • Adjust lighting to create a mildly aversive environment (bright, uniform light).

2. Habituation (Day 1)

   • Place the animal in the center of the maze.
   • Guide the animal gently to the escape hole.
   • Allow it to enter and remain in the escape box for 1–2 minutes.
   • Repeat 1–2 times if necessary.

3. Training Trials (Days 2–4)

   • Conduct 3–5 trials per day per animal.
   • For each trial:
     • Place the animal in an opaque start cylinder in the center.
     • After 10 seconds, lift the cylinder and start the timer.
     • Allow the animal to explore until it enters the escape hole or until 3 minutes have elapsed.
     • If the animal fails to find the hole, gently guide it to the target.
     • Let the animal stay in the escape box for 30–60 seconds.
     • Clean the maze between trials.

4. Probe Trial (Optional, Day 5)

   • Remove the escape box.
   • Place the animal in the center as usual.
   • Allow it to explore the maze for 90–120 seconds.
   • Record the time spent near the former location of the escape hole and search pattern.

5. Data Collection

   • Measure latency to find the target hole.
   • Count errors (incorrect hole visits).
   • Record path length and movement strategy using video tracking if available.

6. Post-Session

   • Return the animal to its home cage.
   • Clean the maze thoroughly.
   • Back up video and behavioral data.

Overview

Developed by Carol Barnes in 1979, the Barnes Maze consists of a circular platform with evenly spaced holes around the perimeter. One of these holes leads to an escape box (target), while the others are false holes (decoys). The open and brightly lit surface creates a mild aversive stimulus that motivates the subject to find and remember the location of the target hole.

Apparatus

• Circular platform (typically 90–120 cm in diameter)
• 20+ equally spaced holes along the edge (number can vary)
• Escape box placed beneath one of the holes
• Bright lighting to provide aversive motivation
• Visual cues (e.g., shapes, colors) placed around the room to support spatial navigation

Procedure

1. Habituation: The animal is placed on the maze with the escape hole visible and guided toward it to become familiar with the task.
2. Training trials: The subject is placed in the center of the platform and must locate the escape box. Over multiple trials, the animal learns to use distal spatial cues to navigate to the correct hole.
3. Probe trials (optional): The escape box is removed to assess memory recall. Metrics such as time spent near the target hole and number of errors are recorded.

Measurements

• Latency to find the escape hole
• Number of errors (visits to incorrect holes)
• Path length
• Search strategy (random, serial, or spatial)
• Time spent in the target quadrant during probe trials

Advantages

• Non-invasive and less stressful than water-based mazes
• Suitable for repeated trials without inducing hypothermia or fatigue
• Ideal for testing aged or genetically modified animals with altered stress responses
• Easily combined with video tracking for detailed movement analysis

Limitations

• Motivation depends on aversive lighting rather than escape from water
• May be less effective in animals with low anxiety or high exploratory drive
• Visual cues must be carefully controlled to avoid confusion

Applications

• Spatial learning and memory studies
• Neurodegenerative disease models (e.g., Alzheimer’s)
• Pharmacological testing
• Genetic and environmental influence on cognition

References

• Barnes, C. A. (1979). Memory deficits associated with senescence: A neurophysiological and behavioral study in the rat. Journal of Comparative and Physiological Psychology, 93(1), 74–104.
• Harrison, F. E., & Hosseini, A. H. (2009). Behavioral assessment of spatial learning and memory in mice using the Barnes maze. Nature Protocols, 4(1), 31–36.