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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.

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Presentation on theme: "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."— Presentation transcript:

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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 Anne Shumway-CookMarjorie H. Woollacott 6- Motor Control And Learning: A Behavioral Emphasis, Fourth Edition by Richard Schmidt, Tim LeeRichard SchmidtTim Lee 7- Motor Learning and Performance by Richard A. Schmidt, Craig A. WrisbergRichard A. SchmidtCraig 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 speed criteria  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

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14 EMG

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16 THE NEUROBIOLOGICAL VIEW 1 skeletal system & muscles: movements possible 2 spinal cord: a)ctrl skeletal muscles in response to sensory info (reflexes) b) implementation of motor commands 3 brainstem: integration & relay of motor and sensory info from brain & spinal cord and in reverse, respectively 4 primary motor cortex (M1): motor commands initiation

17 THE NEUROBIOLOGICAL VIEW ctnd 5 premotor cortex: programs levels of motor cortical processing 6 basal ganglia & cerebellum: modulate activities of hierarchically organized motor ctrl systems

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

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)-length shortens]

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)


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