Overview
This lecture examines the definition and scope of motor control, explaining how humans control body movements and the fundamental challenges that make movement control difficult.
Motor Control: Definition and Field
- Motor control is an ongoing field of scientific study focused on understanding how we control body movements
- Emphasizes principles and mechanisms over memorizing facts, enabling application across diverse contexts
- Movement preparation (planning) occurs in the central nervous system and brain before physical motion begins
- Requires coordinated activity between the central nervous system and musculoskeletal system
- Field extends to motor learning, skill acquisition, early development, and neuromotor dysfunction consequences (e.g., stroke, spinal cord injury)
- Course focuses primarily on motor learning and skill acquisition for professional practice applications
Core Challenges of Motor Control
| Challenge | Description |
|---|
| Noise | Sensory information, signal processing, and muscle commands contain errors/variability; small mistakes occur constantly but are usually corrected automatically |
| Uncertainty | Information needed for movement may be hidden or not yet occurred; predictions made based on past experience (e.g., aiming in changing wind) |
| Redundancy | Multiple movement patterns can achieve the same goal; selecting the appropriate pattern remains debated (e.g., underarm vs. overhead throw) |
| Delays | Nervous system operates slower than electronics; muscles are slow to produce force and relax; reflexes help manage this timing problem |
| Non-stationarity | Constantly changing conditions require flexible commands; subtle differences in posture, fatigue affect needed muscle commands even in repetitive tasks |
| Complexity | Over 80 billion neurons in the central nervous system; calculating muscle force and timing is computationally difficult despite appearing effortless |
Key Principles
- Movement errors (tripping, missing shots, spilling) result from these inherent control challenges
- Humans manage complexity remarkably well and remain unaware of the sophisticated processes underlying daily movements
- Understanding these principles provides a framework for analyzing motor control difficulties and enhancing professional practice
- Comparing human performance to humanoid robots demonstrates how difficult motor control truly is