Foot Fault Score
Per-step categorical score from 0 (total miss) to 6 (correct placement)
ConductVision · Behavioral Analysis
Horizontal Ladder Test
AI-powered limb tracking for fine motor coordination on irregular rungs.
RodentMotor CoordinationAuto Export
ConductVision / Horizontal Ladder Test
Recording / Trial 3subject tracked
Fault Score5.2
Slips3
Accuracy87%
Key Parameters
Metrics automatically extracted by ConductVision.
Slip Count
Total paw slips from rungs across a single crossing
Fall Count
Limb drops through the rungs or complete misses
Crossing Latency
Total time to traverse the full ladder length
Paw Placement Accuracy
Percentage of steps with correct rung contact (score 5–6)
Interlimb Coordination
Forelimb-hindlimb stepping pattern regularity
+ 8 more parameters trackedShow allHide
Forelimb Fault Rate
Proportion of forepaw placements scoring below 5 on the fault scale
Hindlimb Fault Rate
Proportion of hindpaw placements scoring below 5 on the fault scale
Replacement Steps
Limb initially misses then repositions on the rung (score 3)
Correction Steps
Limb adjusts position on the rung after initial contact (score 4)
Compensatory Movements
Adaptive postural adjustments following a slip or miss
Forepaw Digit Flexion
Digit grasp angle on rungs — 90°, 45°, or fully flexed
Left-Right Asymmetry
Difference in fault rate between ipsilateral and contralateral limbs
Session-to-Session Recovery
Change in fault rate across longitudinal test sessions
What is the Horizontal Ladder Test?
The Horizontal Ladder test assesses fine motor control by requiring rodents to traverse a ladder with irregularly spaced rungs. Variable spacing prevents habitual stepping and forces continuous sensorimotor adaptation, making the assay sensitive to subtle deficits that rotarod and beam walk may miss. The apparatus uses transparent acrylic walls for unobstructed multi-angle video recording.
ConductVision automates limb tracking at high frame rates (≥120 fps), classifying each paw placement on a standardized 7-category fault scale — from total miss (0) to correct placement (6). Left-right asymmetry scoring enables lateralized injury assessment in stroke and unilateral spinal cord injury models.
Protocol Parameters
| Parameter | Description | Default |
|---|---|---|
| Ladder Length (Mouse) | Traversable distance between start and goal | 60 cm |
| Ladder Length (Rat) | Traversable distance between start and goal | 100 cm |
| Wall Height (Mouse) | Transparent acrylic side-wall height | 15 cm |
| Wall Height (Rat) | Transparent acrylic side-wall height | 20 cm |
| Rung Diameter | Metal rung cross-section | 3 mm |
| Minimum Rung Spacing | Closest drilled-hole interval for rung placement | 1 cm |
| Elevation | Height above ground to discourage jumping off | 30 cm |
| Habituation Sessions | Familiarization crossings with regular rung spacing | 3–5 sessions |
| Trials per Session | Recorded crossings per test session | 3–5 trials |
| Rung Pattern | Spacing configuration during testing | Variable (irregular) |
| Video Frame Rate | Minimum capture rate for limb-level scoring | ≥ 120 fps |
Interpreting Results
↑
Elevated Foot Fault Rate
Motor coordination deficit — increased proportion of scores 0–4 indicates impaired skilled locomotion after spinal cord or cortical injury.
↑
Increased Left-Right Asymmetry
Lateralized motor impairment — large asymmetry in fault rate between sides indicates unilateral lesion (stroke, hemisection).
↑
More Replacement & Correction Steps
Compensatory motor strategy — the animal detects errors and self-corrects, suggesting partial sensorimotor function remains.
↑
Increased Crossing Latency
Slowed skilled locomotion — longer traverse time reflects cautious movement or difficulty planning limb placement.
↓
Reduced Paw Placement Accuracy
Loss of proprioceptive precision — fewer correct placements (score 5–6) seen in peripheral nerve injury and cerebellar ataxia.
↓
Reduced Digit Flexion Angle
Impaired grip — loss of forepaw digit grasp on rungs indicates fine motor or peripheral nerve dysfunction.
Research Applications
Spinal Cord & Nerve Injury
- Spinal cord injury — gold-standard for graded recovery of skilled locomotion after contusion or hemisection
- Peripheral nerve injury — longitudinal tracking of reinnervation and motor recovery
- Nerve graft and conduit studies — functional endpoint for regeneration research
Stroke & Brain Injury
- Stroke recovery — lateralized limb scoring reveals ipsilateral vs. contralateral deficits
- Traumatic brain injury — fine motor assessment complementing open-field and beam walk
- Cortical lesion mapping — correlating fault patterns with lesion location and size
Neurodegeneration & Pharmacology
- ALS and motor neuron disease — progressive decline in placement accuracy over weeks
- Cerebellar ataxia — interlimb coordination deficits on irregular rung patterns
- Drug screening — neuroprotective and neuroregenerative compound evaluation with quantitative endpoints
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