This document summarizes the organization and function of the motor system, including the spinal motor neuron, motor unit, neuromuscular junction, muscle spindles, stretch reflex, Golgi tendon organ, and feedback inhibition. It describes the role of alpha and gamma motor neurons in voluntary movements and locomotion. It discusses the primary motor cortex, premotor cortex, basal ganglia, cerebellum, and their involvement in motor planning, control, execution, learning, and adaptation. Key structures and pathways that converge on the anterior horn neuron to regulate precise movement are outlined.

1. Organization of Motor System

2. Spinal Motor Neuron

3. Motor Unit

4. Neuromuscular Junction

7. Types of Muscle Contraction

8. Muscle Spindle

9. Stretch Reflex

11. Golgi Tendon Organ

12. Feedback Inhibition: Golgi Tendon Organ

13. Withdrawal Reflex

14. Withdrawal and Crossed Extensor Reflex

15. Alpha and gamma motor neurons are coactivated during voluntary movements

16. Spinal Animal

17. Cat hind limb activity during stepping

18. Locomotor Center in Cat

19. Motor Cortex in precise stepping

20. Locomation

21. Motor cortical center

22. Functional Organization of the Primary Motor Cortex

23. Corticospinal Pathway

24. CorticoRubrospinal Pathway

25. Convergence of Motor Control on the Anterior Motor Neuron

26. Corticomotoneuronal (CM) cell is active depends on the motor task

27. Activity in Individual Neurons of the Primary Motor Cortex Is Related to Muscle Force and Direction of Movement

28. A set-related neuron in the dorsal premotor area becomes active while the monkey prepares to make a movement to the left

29. Motor Cortical Cell Firing with Force Generated

30. Different areas of cortex are activated during simple, complex, and imagined sequences of finger movements (Xenon PET)

31. Cell activity in the motor cortex depends on whether a sequence of movements is guided by visual cues or by prior training

32. The visuomotor transformations required for reaching and grasping involve two different pathways

33. Individual neurons in the ventral premotor area fire during specific hand actions only

34. Motor planning

35. Mirror NeuronsA. Activity in the neuron as the monkey observes another monkey make a precision group.B. Activity in the same neuron as the monkey observes the human experimenter make the precision grip.C. Activity in the same neuron as the monkey itself performs a precision grip. (From Rizzolottiet al 1996.)

36. SummaryPrimary Motor Cortex:Codes force and direction of movementSpinal motor neuron are directly under control for precise movement.Dorsal Premotor CortexMovement related neuron encodes sensorimotor transformation for visual and sensory cueFire before movementVentral Premotor CortexEncodes learned motor act fire before movementAll cortical neurons are adaptable and plastic

37. Basal Ganglia

38. Functional organization of BG

39. Motor Component of Basal Ganglia

40. Basal Ganglia in Executing Patterns of Motor Activity— The Putamen Circuit

41. Cognitive Control of Sequences of Motor Patterns—The Caudate Circuit

42. Neurotransmitters of BG

43. Function of BGVoluntary movementInitiation of movementControl of ramp movementChange from one pattern to otherProgramming and correcting movement while in progress (thalamocortical circuts)Postural controlRighting reflexAutomatic associated movement (walking)Control of muscle toneReticulospinal Vestibulospinal

44. Cerebellum

45. Functional organization of cerebellum

46. Afferent Pathway of Brain

47. Spinocerebellar pathway

48. Output Signals from the Cerebellum

49. Neocerebellum

50. Vestibulocerebellum

51. The spinocerebellum contains two somatotopic neural maps of the body

52. Neuronal Circuit of the Functional Unit

54. Control of voluntary movementExecutionPlanningBasal GangliaAssociation cortexPremotor + Motor cortexMovementIdeaLateral cerebellumIntermediate Cerebellum