Passive Avoidance (Step-Through)
Overview
The passive avoidance (step-through) test measures inhibitory learning — the ability of an animal to suppress a natural behavior (entering a dark compartment) after that behavior has been paired with an aversive outcome. The apparatus consists of a brightly lit compartment connected to a dark compartment through a guillotine door. Rodents naturally prefer dark enclosed spaces, so naive animals rapidly step through to the dark side. During training, entry into the dark compartment triggers a brief foot shock.
Retention is tested 24–72 hours later by placing the animal back in the light compartment and measuring the latency to enter the dark side. Animals that have formed a strong aversive memory will show dramatically increased step-through latency, often remaining in the light compartment for the entire test duration (typically 300 s cutoff). The simplicity of the single-trial training protocol makes passive avoidance one of the most efficient learning and memory assays available.
ConductMaze automates guillotine door control, detects compartment entry via IR beam break, delivers calibrated shock, and records step-through latency with millisecond precision. The software supports configurable training–test intervals, multiple retention tests, and group-level analysis of memory consolidation and extinction.
Trial Flow
Habituation
Place animal in light compartment, door closed, 30 s exploration
Door Opens
Guillotine door opens, latency timer starts
Step-Through
Animal crosses to dark compartment (IR beam break)
Shock Delivery
Brief foot shock (0.3–0.5 mA, 1–2 s) upon entry
Retention Test
24–72 h later: repeat without shock, measure step-through latency
Record Latency
Log step-through latency (max 300 s cutoff)
End
Remove animal, clean apparatus
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
| Shock intensity | mA | 0.4 | Foot shock amplitude during training |
| Shock duration | seconds | 2 | Duration of foot shock |
| Cutoff latency | seconds | 300 | Maximum time allowed in retention test |
| Retention interval | hours | 24 | Time between training and retention test |
| Habituation duration | seconds | 30 | Time in light compartment before door opens |
| Door open delay | seconds | 5 | Delay from placement to door opening (after habituation) |
Metrics
| Metric | Unit | Description |
|---|---|---|
| Step-through latency (training) | seconds | Time to enter dark compartment on training day |
| Step-through latency (test) | seconds | Time to enter dark compartment on retention test |
| Latency ratio | ratio | Test latency / training latency — index of memory strength |
| Avoidance success | boolean | Whether animal reached cutoff without entering dark side |
| Number of entries | count | Total dark compartment entries during test (if door stays open) |
| Time in light compartment | seconds | Total time spent in light compartment during test |
Sample Data
| Subject | Group | Training Latency (s) | Test Latency (s) | Latency Ratio | Avoidance |
|---|
Representative data for illustration purposes. Actual values will vary by species, strain, and experimental conditions.
Applications
- 1Memory consolidation — single-trial design isolates consolidation from acquisition
- 2Cholinergic drug screening — highly sensitive to muscarinic antagonists (scopolamine) and acetylcholinesterase inhibitors
- 3Alzheimer disease models — detects hippocampal-dependent memory deficits in transgenic mice
- 4Amnestic agent testing — post-training drug administration probes consolidation mechanisms
- 5Nootropic evaluation — dose-response curves for cognitive enhancers
Related Protocols
Compatible Products
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