Burrowing Test
Overview
The burrowing test measures the innate species-typical behavior of rodents to displace material from a tube placed in their cage, providing one of the most sensitive assays for detecting sickness behavior, hippocampal dysfunction, and prion-related neurodegeneration. A cylindrical tube (approximately 20 cm long, 6.8 cm diameter for mice) filled with 200 g of food pellets or gravel is placed in the home cage, and the weight of material remaining in the tube is measured at 2 hours and again the following morning to calculate total displacement. Healthy mice typically displace over 90% of the substrate within the first two hours, making reductions in burrowing a rapidly detectable phenotype that precedes motor deficits and weight loss in many disease models.
Burrowing is exquisitely sensitive to hippocampal damage, with bilateral hippocampal lesions reducing displacement by 50-80% without affecting general locomotor activity or feeding behavior. The assay has been extensively validated in prion disease models, where burrowing deficits emerge weeks before clinical signs, and in models of peripheral and central inflammation where lipopolysaccharide, interleukin-1-beta, or tumor necrosis factor-alpha dose-dependently suppress displacement. The two-timepoint design (2 hours and overnight) dissociates acute motivational deficits from sustained impairments, as some manipulations selectively impair early rapid burrowing while leaving overnight displacement intact.
ConductMaze integrates the burrowing test with automated weight logging via a cage-mounted precision balance that records substrate weight at user-defined intervals, enabling continuous displacement kinetics rather than just two-timepoint snapshots. The software computes displacement rate curves, identifies the onset and plateau of burrowing bouts, and flags animals whose displacement falls below a configurable threshold indicative of welfare concerns. Data are automatically linked to subject metadata, treatment groups, and concurrent home-cage monitoring streams for multimodal behavioral phenotyping.
Trial Flow
Tube Preparation
Fill burrowing tube with exactly 200 g of food pellets or gravel; seal the closed end and position open end elevated 3 cm
Animal Acclimation
Habituate mice to the burrowing tube for 2 consecutive nights before the test day to establish baseline performance
Test Tube Placement
Place the pre-weighed, filled tube in the home cage at the onset of the dark cycle
2-Hour Weigh
Remove the tube after 2 hours and weigh remaining substrate to calculate acute displacement
Tube Return
Return tube to cage for overnight burrowing; record exact time of replacement
Overnight Weigh
Remove tube the following morning and weigh remaining substrate for total overnight displacement
Displacement Calculation
Compute grams displaced at 2 h and overnight: starting weight minus remaining weight at each timepoint
Session End
Clean tube and cage; record environmental conditions and any visible health observations
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
| Substrate Type | enum | food_pellets | Material filling the burrowing tube: food_pellets, gravel, or sand |
| Substrate Weight | float | 200 | Starting weight of substrate loaded into the tube in grams |
| Tube Length | float | 20.0 | Length of the burrowing tube in centimeters |
| Tube Diameter | float | 6.8 | Internal diameter of the burrowing tube in centimeters |
| Elevation Angle | float | 3.0 | Height of the open end above cage floor in centimeters to prevent passive spillage |
| Acute Timepoint | duration | 7200 | Time of first weighing after tube placement in seconds (default 2 hours) |
| Overnight Duration | duration | 43200 | Total assessment duration from placement to final weighing in seconds (default 12 hours) |
| Habituation Nights | integer | 2 | Number of nights the tube is available before the scored test session |
| Housing Condition | enum | single | Single-housed or group-housed during test (single recommended for individual scoring) |
Metrics
| Metric | Unit | Description |
|---|---|---|
| 2-Hour Displacement | g | Grams of substrate displaced from the tube within the first 2 hours |
| Overnight Displacement | g | Total grams displaced from tube placement to next-morning weighing |
| 2-Hour Displacement Percent | % | Percentage of starting substrate displaced at the 2-hour timepoint |
| Overnight Displacement Percent | % | Percentage of starting substrate displaced by overnight assessment |
| Displacement Rate | g/h | Rate of substrate displacement calculated from continuous weight monitoring |
| Burrowing Latency | min | Time from tube placement to first detectable displacement event |
| Habituation Baseline | g | Average displacement across habituation nights used as within-subject baseline |
Sample Data
| Subject | Treatment | 2h Displacement (g) | Overnight Displacement (g) | 2h Percent (%) | Overnight Percent (%) | Latency (min) |
|---|
Representative data for illustration purposes. Actual values will vary by species, strain, and experimental conditions.
Applications
- 1Sickness behavior detection — identifying subclinical illness or inflammatory states days before overt clinical signs appear in infection and neurodegeneration models
- 2Prion disease staging — using burrowing deficits as an early, quantitative biomarker of prion pathology that precedes motor symptoms by weeks
- 3Hippocampal lesion validation — confirming the extent and functional impact of hippocampal damage from surgical, excitotoxic, or genetic manipulations
- 4Anti-inflammatory drug efficacy — measuring dose-dependent rescue of burrowing after LPS or cytokine challenge as a functional recovery endpoint
Related Protocols
Compatible Products
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