فصل سوم- فرضيه ها و استراتژيهاي حركات 3-1 ‍ Centeralism 3-2 Prepheralism 3-3 Motor Program

2. فصل سوم- فرضيه ها و استراتژيهاي حركات 3-1 ‍Centeralism 3-2 Prepheralism 3-3 Motor Program 3-4 Equilibim Hypothesis 3-5 Impedance Control فصل چهارم- حركتهاي متناوب و راه رفتن 4-1 ويژه گيهاي راه رفتن 4-2 Cenral Pattern Generator فصل پنجم- ياد گيري حركت و مدلهاي ارائه شده براي حركت 5-1 Motor Learning 5-2 مدلهاي ارائه شده 5-2-1 Internal Model 5-2-2 Smith Predictor 5-2-3 Model Predictive Control فصل ششم- معلوليت و بيماريهاي حركتي 6-1 FES 6-2 Parkinson 6-3 Huntington 6-4 ALS

3. References: • 1-Neurological Control Systems: Studies in Bioengineering ,Stark L, 1968- • 2-Muscle Alive, Basmajian JV • 3- The Neural Basis of Motor Control, Brooks, V. B., (1986).Oxford Univ. Press. • 4-Multiple Muscle Systems, M. Winters and S. L-Y. Woo (ed.),Springer-Verlag(1990) • 5-Motor Control: Theory and Practical Applications by Anne Shumway-Cook, Marjorie H. Woollacott • 6- Motor Control And Learning: A Behavioral Emphasis, Fourth Edition by Richard Schmidt, Tim Lee • 7- Motor Learning and Performance by Richard A. Schmidt, Craig A. Wrisberg • 8- The Computational Neurobiology of Reaching and Pointing By Reza Shadmehr and Stiven P. Wise, MIT Press, 2005

4. HUMAN MOTOR CONTROL SYSTEM Overview

5. MOTOR BEHAVIORS CLASSIFIED ON FUNCTIONAL PROPERTIES Movements: brief,discrete, unitary muscle activities, limited to single parts Acts: complex, sequential behaviors, goal-oriented, different body parts included (action patterns) • more restricted CNS regions that ctrl movements than acts

6. QUESTION OF BASIC UNITS OF MOVEMENTS Reflexes : “simple, highly stereotyped and unlearned responses to external stimuli”. Their magnitude related to stimulus intensity. Spinal cord roots: dorsal contain sensory fibers, ventral contain motor fibers

7. Some reflexes short pathways in spinal cord linking dorsal & ventral roots, others longer loops (spinal cord interconnections or to the brain) Reflexes as basic units of movement (Sherrington, early 20th century) BUT: Speech as ordered stimulus-response units problematic So...

8. MOTOR PLANS/PROGRAMS complex movements & acts produced and controlled by set of commands to muscles, established before onset. Feedback on execution

9. THE CONTROL SYSTEMS VIEW • Machine design vocabulary: accuracy and speedcriteria • Closed-loop and Open-loop ctrl mechanisms to optimize performance

10. CLOSED-LOOP CTRL MECHANISMS • continuous feedback from controlled system to controller (e.g. driving) • slow, sustained movements (ramp/smooth) • accuracy & flexibility at speed expense

11. OPEN-LOOP CTRL MECHANISMS • activity preprogrammed • sensor measured output(no external form of feedback • rapid responses -ballistic movements (e.g. throwing a fastball) • no feedback/ error reduction: anticipation (prior learning)

12. MOTION ANALYSIS & MEASUREMENT • photographic, computer graphic techniques • EMG (electromyography): recording muscle electrical activity fine needle electrodes (skin/muscle) • measure contraction involved in activity

14. EMG

15. EMG

16. THE NEUROBIOLOGICAL VIEW • skeletal system & muscles: movements possible • spinal cord: • a)ctrl skeletal muscles in response to sensory info (reflexes) • b) implementation of motor commands • brainstem: • integration & relay of motor and sensory info from brain & spinal cord and in reverse, respectively • primary motor cortex (M1): • motor commands initiation

17. THE NEUROBIOLOGICAL VIEW ctnd • premotor cortex: • programs levels of motor cortical processing • basal ganglia & cerebellum: • modulate activities of hierarchically organized motor ctrl systems

18. Limbic System Highest Level Need Associative Cortex Plan Middle Level Cerebellum Motor Cortex Basal Ganglia Motor Program Spinal Cord Lowest Level Musculo-Skeletal System Movement

19. VOLUNTARY MOVEMENTS vs REFLEXES • VOLUNTARY • purposeful tasks • open to experience/learning • Internally generated (potentially) • dissociated stimulus aspects : informational content-capacity to trigger movement (in higher motor system’s levels) • REFLEXES • stereotyped stimulus-response relationship • environmentally triggered • stimulus aspects linked • organized in spinal & brain stem circuits in response to somatosensory, vestibular stimuli

20. MUSCULAR CTRL OF ACTION OF SKELETAL SYSTEM • muscles generate force by contraction • springlike properties influence timing & forces generated • Connected to bones by tendons/ attachment indicative of mediated movement • reciprocal arrangements around joints (flexion/extension) (e.g. arm biceps/triceps)- antagonists & synergists (act together) • coordinated action around joint might require set of motoneurons excited the antagonistic set inhibited • Limb locked in position by contraction of opposed muscles • body posture maintenance, movement around joint, other muscles not act on skeleton (abdomen contraction)

21. MUSCLE TYPES • smooth (stomach): contractions regulated by autonomic system • Skeletal: under voluntary control [Muscle fibers overlapping filaments(made of actin & myosin) give the striped appearance M.fibers : single large cells with many nuclei (thousands compose a muscle) Contraction increases overlap(myosin binds to actin, filaments slide past one another)-lengthshortens]

22. MUSCLE FIBERS TYPES 1) fast : for quick, accurate not maintained movement (e.g. extraocular muscles composed of those) 2) slow : resiliency to fatigue (posture maintenance)