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• Final common pathway The lower motor neurons which control all movements by essential signaling conduits between the nervous system and skeletal muscle fibers
• Spinal reflexes Mediated by neural circuits of the vertebrate spinal cord
• The Stretch reflex Oppose a stretch of a muscle like the knee-jerk response to a tap
• Muscle spindles specialized sensory receptor that activates the stretch reflex, a kind of proprioceptor
• Intrafusal fibers 8 to 10 specialized muscle fibers in the muscle spindle, contained within a capsule of connective tissue
• Extrafusal fibers Outside of the capsule, the normal working contractile muscle fibers that generate movements
• Reciprocity When one muscle is commanded to contract the other one in the pair is commanded to relax
• Alfa-Gamma-Coactivation ensures that the ongoing sensitivity of the muscle spindle is maintained during muscle shortening, and it allows the spindle to determine whether the muscle shortens during the intended movement
• Rhythmic behavior Stereotyped, repetitive sequences of movement such as walking, swimming and flying
• Primary motor cortex Motor cortex with upper motor neurons that control movement indirectly via interactions with interneurons and lower motor neurons in the brainstem and spinal cord
• Cerebellum Large part at the dorsal side of the hindbrain present in all vertebrates. Involved in the coordination of movement and can correct errors signals and thereby ongoing movements
• Basal ganglia Are set of nuclei located in the forebrain and midbrain and are important in selecting movements, choosing which movement to preform between competing movements and starting the selected movement
• Loop there the output of the circuit loops back to the site of the circuits input. Important for motor control, emotions and other brain activities

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