Topic overview

Start with the big picture

The lesson begins with the motor cortex: area 4 executes voluntary, skilled movement, while area 6 helps plan and prepare complex actions. It then follows descending control through the corticospinal and extrapyramidal pathways, and explains how motor units are recruited to grade force. Muscle spindles and Golgi tendon organs provide sensory input for reflex regulation, with gamma motor neurons adjusting spindle sensitivity. The basal ganglia modulate movement initiation and scaling; the cerebellum compares intended with actual movement to support error correction. The topic also introduces feedforward and feedback control, spinal central pattern generators, and clinical distinctions associated with upper and lower motor neuron lesions. Together, these concepts show how movement depends on coordinated planning, execution, and ongoing regulation.