Central Pattern Generators (CPGs):
- Responsible for generating basic rhythmic movements without constant conscious input.
- Examples of CPG-controlled movements include:
- Chewing
- Swallowing
- Walking
- Hiccups
- Yawning
- Vomiting
- Coughing
- Breathing
- Locomotion (partially - gait)
How CPGs Work:
- Composed of interconnected neurons in the brainstem.
- Generate a baseline movement pattern (e.g., jaw closure-opening in chewing).
- Can be reconfigured to produce variations of the baseline pattern (e.g., chewing gum vs. regular chewing).
- Can respond to sensory feedback and adjust the movement pattern accordingly (e.g., walking faster on a treadmill).
CPGs and Locomotion:
- Locomotion in humans involves gait (leg movements) and postural control (balance).
- The gait CPG is shared between cats and humans.
- Cats with spinal cord lesions can still walk on a treadmill because their gait CPG is located in the spinal cord.
- Humans with spinal cord lesions often lose the ability to walk because the balance component (not solely gait) is disrupted. The human gait CPG also relies more on brainstem neurons in addition to spinal cord neurons.
CPGs and Neurological Disorders:
- Damage to the brainstem-spinal cord connection can disrupt CPG function and lead to walking impairments.
- Currently, there is no effective treatment to restore walking ability after a spinal cord injury due to CPG dysfunction.
- Researchers are exploring therapeutic options to potentially improve CPG function in the future.