Elevated Plus Maze
Overview
The elevated plus maze (EPM) is the most widely used test for anxiety-like behavior in rodents, exploiting the natural conflict between the drive to explore novel environments and the aversion to open, elevated spaces. The apparatus consists of four arms arranged in a plus shape, elevated 50–70 cm above the floor: two enclosed arms (with 30–40 cm walls) and two open arms (no walls or low ledges). Animals are placed at the center junction and allowed to freely explore for 5 minutes.
Anxious animals spend more time in the enclosed arms and make fewer entries into the open arms. The ratio of open arm time to total arm time and the ratio of open arm entries to total entries are the primary anxiety indices. The test is sensitive to both anxiolytic drugs (benzodiazepines increase open arm exploration) and anxiogenic manipulations (stress, CRF administration decrease it). A single 5-minute test is typically used because prior exposure reduces the anxiolytic sensitivity of the maze (one-trial tolerance).
ConductMaze uses overhead video tracking to automatically score arm entries, time in each zone (open arms, closed arms, center), distance traveled, and risk assessment behaviors (head dips over open arm edges, stretched-attend postures). The software defines arm boundaries, detects entries based on center-point or four-paw criteria, and generates heat maps, transition matrices, and ethological behavioral profiles.
Trial Flow
Preparation
Verify lighting (40–60 lux on open arms); clean maze with 70% ethanol
Place Animal
Place animal at center junction facing open arm; start recording
Free Exploration
5 min uninterrupted exploration with video tracking
Zone Scoring
Track time and entries in open arms, closed arms, center
Ethological Scoring
Count head dips, SAPs, rearing, grooming events
End
Remove animal; clean maze between subjects
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
| Test duration | minutes | 5 | Total exploration time (standard is 5 min) |
| Open arm light level | lux | 50 | Illumination on open arms (anxiogenic factor) |
| Maze height | cm | 50 | Elevation above floor |
| Entry criterion | enum | center-point | Arm entry detection: center-point or four-paw criterion |
| Species | enum | mouse | Mouse (5 cm arm width) or rat (10 cm arm width) dimensions |
| Starting position | enum | center-facing-open | Placement position and orientation |
Metrics
| Metric | Unit | Description |
|---|---|---|
| Open arm time | seconds | Total time spent on open arms |
| Open arm entries | count | Number of entries into open arms |
| Open arm time % | % | Open arm time / (open + closed arm time) × 100 |
| Open arm entry % | % | Open arm entries / total arm entries × 100 |
| Closed arm entries | count | Number of entries into closed arms (locomotor activity index) |
| Head dips | count | Exploratory head dips over edge of open arms (risk assessment) |
| Stretched-attend postures | count | Body stretch toward open arm without full entry (risk assessment) |
| Total distance | cm | Total distance traveled during test (locomotor control) |
Sample Data
| Subject | Group | Open Arm Time % | Open Arm Entries | Closed Entries | Head Dips | Distance (cm) |
|---|
Representative data for illustration purposes. Actual values will vary by species, strain, and experimental conditions.
Applications
- 1Anxiolytic drug screening — gold standard for benzodiazepine, SSRI, and novel anxiolytic efficacy
- 2Anxiety phenotyping — baseline anxiety profiles across strains, sexes, and genetic models
- 3Stress models — chronic mild stress, social defeat, and early life stress anxiety phenotyping
- 4GABAergic pharmacology — GABA-A receptor subtype-selective compound testing
- 5Translational anxiety research — face validity for approach-avoidance conflict in human anxiety
Related Protocols
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