Motor system i spinal motor system: major components of motor system. Parietal cortex: visual and proprioceptive processing gives positional info. Motor cortex: compute forces needed to cause desired motor action. Brainstem: tells spinal cord how to maintain balance during movement. Spinal cord: effects movement, reflex stability, and relays sensory info. Basal ganglia: learning and stability of movements, emotional aspects of movement. Motor system diseases: how spinal cord injury results in paralysis. Initial injury in small region growth of damaged area hemorrage of blood vessels. Glu release neuron excitotoxicity and glia apoptosis. Paralysis can be partially overcome with direct electrical stimulation from neural prosthetic: other diseases/conditions. Polio: virus kills motoneurons directly, post-polio syndrome includes motor unit enlargement followed by muscle breakdown. Als: slow degeneration of motorneurons and motor cortex. Motor stroke: spinal motoneurons not affected, but central control is weak. Rigor mortis: stiff muscles after death, no atp available for myosin detachment.