1. ANATOMY AND PHYSIOLOGY OF MOTOR SYSTEMS CHAPTER V

2. Motor pathways

3. Somatotopic organization of the motor cortex

4. Cortical motor areas The central sulcus divides motor and sensory areas SUPPLEMENTARY CORTICAL AREAS PROVIDE INPUT TO MOTOR CORTEX

5. LATERAL DESCENDING SYSTEM CORTICOSPINAL TRACT –CONNECT DIRECTLY TO ALPHA MOTONEURONS, OR THROUGH PROPRIOSPINAL INTERNEURONS RUBROSPINAL TRACT –FROM NUCLEUS RUBER TO PROPRIOSPINAL INTERNEURONS

6. Descending motor pathways Lateral system

7. The medial descending motor pathways

8. Motor pathways from the brainstem

9. Projections from motor cortex (MI) to the spinal cord Projection of dorsal horn to the somatosensory cortex

11. Connections between the basal ganglia and the primary motor cortex (MI)

12. INFORMATION FROM THE MOTOR CORTEX IS PROCESSED IN THE BASAL GANGLIA AND RETURNED TO THE MOTOR CORTEX THE THALAMUS CONDUCT THE INFORMATION BACK TO THE MOTOR CORTEX THE DISTINCTION BETWEEN PYRAMIDAL AND EXTRAPYRAMIDAL SYSTEMS THEREBY BECOMES IRRELEVANT

14. Motor systems are complex

15. Two descending motor tracts The alpha- motoneuron is the final common pathway

16. Anatomical localization of basal ganglia and motor thalamus

17. Connections between the cerebral cortex and the cerebellum

18. The alpha- motoneuron innervates muscles

19. The alpha-motoneurons (common final pathway) receive many inputs Some are facilitating and some are inhibitory

20. The anatomical basis for the stretch reflex

21. Motoneurons receive excitatory input from muscle spindles (length), and inhibitory input from tendon organs (tension)

22. Recording from the exposed spinal cord D and I waves

23. Blood supply to the spinal cord Mainly two sources: –The anterior spinal artery –Posterior spinal artery –Segmental arteries Dorsal and ventral portions of the spinal cord have mostly different blood supplies Large degree of individual variability

24. Blood supply to the spinal cord

25. Anterior spinal artery Number of feeder arteries varies

26. Two posterior spinal arteries Number of feeder arteries varies

27. Activation of motor tracts Transcranial magnetic stimulation of the motor cortex Transcranial electrical stimulation of the motor cortex Electrical stimulation of the spinal cord

28. Magnetic stimulation of the motor cortex Non-invasive Technically difficult to apply Need trains of stimulation, which is difficult to achieve

29. Transcranial electrical stimulation of the motor cortex Non-invasive Can easily produce trains of impulses High voltage may seem a risk

30. Electrical stimulation of the spinal cord Produces effective stimulation of spinal cord Invasive Not clear if only motor pathways are stimulated

31. Recording of responses Electromyographic potentials Compound action potentials from motor nerves

32. Electromyographic potentials Large potentials Cannot be done with muscle relaxation

33. Compound action potentials Can be recorded with muscle relaxation Amplitude is small

34. Recording from the exposed spinal cord D and I waves

35. Recordings from the surface of the spinal cord in a monkey in response to stimulation of the cerebral cortex Transcranial magnetic stimulation Transcranial electrical stimulation Direct electrical stimulation D I1I1

36. Recordings from the surface of the spinal cord in a 14 year old patient Undergoing a scoliosis operation. Transcranial electrical stimulation at different strengths (100%=750V at Cz and 6 cm anterior)

37. Effect of placement of stimulating electrodes Deletis and Shils 2002

38. Comparison between transcranial and direct stimulation of the motor cortex

39. Deletis and Shils 2002 Techniques for recording motor evoked potentials

43. Repeating trains can increase the EMG responses from the right abductor hallucis brevis in response to trains of five electrical impulses to scalp (C3-C4). Deletis and Shils 2002

45. Using BSM, surgeon can get anatomical guidance to enter the brainstem safely. From Morota N, Deletis V, Epstein FJ, et al: Brain stem mapping: neurophysiological localization of motor nuclei on the floor of the fourth ventricle. Neurosurgery 37: 922-930, 1995

46. Corticobulbar MEPs - Recordings in IV Ventricle Mapping - Recordings

47. Modulation of the monosynaptic stretch reflex

48. The Hoffmann reflex Amplitude of Hoffmann (H) Response, and the direct muscle (M) response.

49. DESCENDING MOTOR ACTIVITY IS AFFECTED BY ATTENTION

51. DESCENDING MOTOR ACTIVITY IS AFFECTED BY ANESTHESIA

52. EFFECT OF INCREASING CONCENTRATION OF ISOFLURANE ON COMPOUND MUSCLE ACTION POTENTIAL IN RESPONSE TO TRANSCRANIAL ELECTRICAL MOTOR CORTEX STIMULATION FROM SLOAN 2002

53. EFFECT OF INCREASING CONCENTRATION OF ISOFLURANE ON EPIDURAL RESPONSE (D AND I WAVES) TO TRANSCRANIAL ELECTRICAL MOTOR CORTEX STIMULATION FROM SLOAN 2002

54. EFFECT OF INCREASING CONCENTRATION OF NITROUS OXIDE ON COMPOUND MUSCLE ACTION POTENTIAL IN RESPONSE TO TRANSCRANIAL ELECTRICAL MOTOR CORTEX STIMULATION FROM SLOAN 2002

55. EFFECT OF INCREASING CONCENTRATION OF NITROUS OXIDE ON EPIDURAL RESPONSE TO TRANSCRANIAL ELECTRICAL MOTOR CORTEX STIMULATION FROM SLOAN 2002

56. EFFECT OF INCREASING DOSES OF ETOMIDATE ON COMPOUND MUSCLE ACTION POTENTIAL IN RESPONSE TO TRANSCRANIAL ELECTRICAL MOTOR CORTEX STIMULATION FROM SLOAN 2002

57. EFFECT OF INCREASING DOSE OF ETOMIDATE ON THE EPIDURAL RESPONSE TO TRANSCRANIAL ELECTRICAL MOTOR CORTEX STIMULATION FROM SLOAN 2002

58. EFFECT OF INCREASING DOSES OF PROPOFOL ON COMPOUND MUSCLE ACTION POTENTIAL IN RESPONSE TO TRANSCRANIAL ELECTRICAL MOTOR CORTEX STIMULATION FROM SLOAN 2002

59. EFFECT OF INCREASING DOSES OF PROPOFOL ON EPIDURAL RESPONSE TO TRANSCRANIAL ELECTRICAL MOTOR CORTEX STIMULATION FROM SLOAN 2002

60. RECORDINGS FROM THE EPIDURAL SPACE WITH AND WITHOUT MUSCLE RELATION IN RESPONSE TO TRANSCRANIAL ELECTRICAL STIMULATION FROM SLOAN 2002

61. OPERATIONS FOR SPINAL DEFORMITIES

67. TEST OF LEVEL OF MUSCLE RELAXATION