1. Making Things Happen Simple Motor Control How Your Brain Works - Week 6 Dr. Jan Schnupp jan.schnupp@dpag.ox.ac.uk HowYourBrainWorks.net

2. “Efferents and Effectors” “Efferent” nerves carry impulses “away” from the central nervous system. Eventually they have to end either in muscles or in glands. Physiologists distinguish 3 types of muscle: “smooth”, “cardiac” and “striate” (or skeletal”)

3. Skeletal Muscle There are ca 640 skeletal muscles in a human body

4. Nervous Control of Skeletal Muscle Motor Cortex Basal Ganglia Cerebellum Spinal Cord Muscle

5. Muscle Fibre Structure axons muscle fibres muscle

6. Organisation of Muscle Fibres (actin) (myosin)

7. Ca ++ exposes Myosin Binding Sites

8. The Myosin Cycle 1 1 2 2 3 3 4 4 1.Myosin binds to actin. 2.Myosin head bends backward, releasing ADP and pulling itself forward. 3.ATP binds to myosin, causing release from actin. 4.Myosin uses energy from ATP hydrolysis to stretch itself, ready to undergo new binding and pulling cycle.

9. Motor Units

10. Muscle Spindles

11. The Stretch Reflex

12. Muscles tend to be arranged in pairs Muscles can only contract. If one muscle bends a limb (the “flexor”) then there must be another muscle to stretch it (the “extensor”). Muscles are therefore typically arranged in agonist-antagonist pairs.

13. Spinal Cord Antagonist Circuits Matthews “Neurobiology” Figure 8-3

14. Postural support through spinal reflexes

15. Spinal Pattern Generators

16. Spinal cord pattern generators

17. Headless Chicken Warning: some viewers may find the content of this video clip distressing.

18. Break

19. Motor Related Areas of Cortex Somatosensory Cortex Somatosensory Cortex Somatosensory Cortex Premotor Area Frontal Eye FieldsPrimary Motor Cortex Supplementary Motor Area Broca’s Area

20. Penfield’s Homunculi

21. The Cortico- spinal Tract

22. Motion Direction Sensitivity in Monkey Primary Motor Cortex Georgopoulos et al, Science 1986

23. Silicon Array Electrodes

24. Primate moving robot arm

25. Human Primate Matthew Nagel

26. What about “Higher Order” Motor Cortex? Somatosensory Cortex Somatosensory Cortex Somatosensory Cortex Premotor Area Frontal Eye FieldsPrimary Motor Cortex Supplementary Motor Area Broca’s Area

27. Mirror Neurons

28. Broca’s Area Broca’s aphasia is usually associated with lesion to the left frontal cortex. See here the brain of Broca’s Patient, Mr Leborgne (“TanTan”) features a large lesion in Broca’s area.

29. Motor Aphasia

30. Motor Aphasia 2

31. Wernicke’s Area Wernicke’s aphasias are often associated with lesions at the boundary of the superior temporal and parietal lobes on the left hemisphere.

32. A Patient with Wernicke’s Aphasia From the archives of the University of Wisconsin

33. The Arcuate Fasciculus Big fibre bundle connecting Broca’s and Wernicke’s Areas http://www.biocfarm.unibo.it/aunsnc/pictef14.html