Catalepsy Bar Test
Overview
The catalepsy bar test measures the inability to correct an externally imposed abnormal posture, a hallmark of extrapyramidal motor dysfunction. The animal's forepaws are placed on an elevated horizontal bar, and the latency to voluntarily step down or reposition is recorded. Catalepsy is a core feature of dopamine D2 receptor blockade and serves as a primary preclinical screen for antipsychotic-induced extrapyramidal side effects and parkinsonian akinesia.
The principal dependent variable is descent latency (time from placement to first corrective movement). Additional measures include the catalepsy intensity score across graded bar heights, dose-response curves for drug-induced catalepsy, and reversal of catalepsy by anti-parkinsonian agents. Repeated testing across time points after drug administration generates full temporal profiles of cataleptic episodes.
ConductMaze automates the catalepsy bar test through precision-machined bars at standardized heights, force-sensitive contact pads that detect the exact moment paws leave the bar, and automatic trial timing with configurable cutoff durations. The system eliminates scorer subjectivity in determining movement onset, supports multi-height protocols in a single session, and logs time-stamped descent events for pharmacokinetic correlation.
Trial Flow
Bar Selection
Select bar height for current trial from protocol sequence
Paw Placement
Place animal forepaws on the bar; start timing on release of animal
Contact Monitor
Force pads continuously detect paw contact with bar surface
Movement Check
Determine if animal initiates corrective movement or cutoff is reached
Latency Record
Log descent latency, bar height, and trial outcome
Next Trial
Advance to next bar height or time point after inter-trial interval
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
| Bar Heights | array | 3,6,9 | Sequence of bar heights to test in centimeters |
| Cutoff Time | integer | 180 | Maximum observation time per trial in seconds |
| Trials Per Height | integer | 3 | Number of repeated trials at each bar height |
| Inter-Trial Interval | integer | 30 | Rest period between consecutive trials in seconds |
| Contact Threshold | float | 0.5 | Minimum force in grams to register paw contact |
Metrics
| Metric | Unit | Description |
|---|---|---|
| Descent Latency | seconds | Time from placement to voluntary corrective movement |
| Catalepsy Score | score | Composite score across bar heights (sum of latencies) |
| Cutoff Proportion | percent | Percentage of trials reaching the maximum cutoff time |
| Height Effect Slope | s/cm | Rate of latency increase per centimeter of bar height |
| Time Course AUC | sec*min | Area under the latency vs. time curve for temporal profiling |
| First Corrective Movement | type | Classification of first movement: step down, paw lift, or postural shift |
Sample Data
| Subject | Group | Bar Height (cm) | Trial | Descent Latency (s) | Movement Type |
|---|
Representative data for illustration purposes. Actual values will vary by species, strain, and experimental conditions.
Applications
- 1Antipsychotic screening \u2014 predicting extrapyramidal liability of novel neuroleptic compounds
- 2Parkinson's disease \u2014 modeling akinesia and rigidity from dopamine depletion or D2 blockade
- 3Anti-parkinsonian drug development \u2014 evaluating anticholinergics, adenosine A2A antagonists, and other reversal agents
- 4Basal ganglia circuitry \u2014 dissecting contributions of direct and indirect pathway to postural control
Related Protocols
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