This lecture segment focuses on volitional movements, the first category of self-generated movements initiated by the forebrain.
Key Points
- Volitional movements are also called deliberate, intentional, or praxis movements.
- Examples include:
- Fine motor skills like writing and turning a page.
- Playing musical instruments (hands, legs, lips).
- Facial expressions, speech, and manipulating objects in the mouth.
- Volitional movements rely on descending information from the neocortex, particularly the primary motor cortex.
- Signals travel down:
- Corticospinal tract (to motor neurons in the spinal cord) for limb and appendage movements.
- Corticobulbar tract (to motor neurons in the brainstem) for facial expressions, upper airway, and tongue movements.
- Damage to these tracts (e.g., from strokes or ALS) disrupts these fine motor skills, especially in the distal limbs (hands, wrists, fingers). Axial movements (trunk) are less affected.
Additional Notes
- The lecture mentions the corticospinal and corticobulbar tracts as pathways for volitional movements.
- The next section will discuss how volitional movements differ from emotional movements.