فصل سوم- فرضيه ها و استراتژيهاي حركات 3-1 centeralism 3-2 prepheralism...
TRANSCRIPT
Ê¿Ô� � -Ê^ ÉZƼf Ì {\ ·Z�»� ÂW�� � � � � � � � �
cZ̸ -µÁY¶ §�1-1½M Y¿YÁd¯ u� �
Êf u Y»Ác Z uÉ Â·ÂȨ̈� � � � � � -¹Á{¶ §�2-1cÔ� �2-2Zz¿�2-3¤» {Êf u Y»� � � � �
2-3-1Ärz»
2-3-2Êf u «� � �2-3-3É ZÌaÉZÅÄ°^� �
2-4Êf uÉZÅ Â À� � � �2-4-1Ê¿Ô Á{� �2-4-2Ê¿Ô ½Á| ¿Ze� �2-4-3¶ »ÉZÅÃ| ¿ ̳� �2-4-4º q�
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 رفتنگيهاي راه رفتن ويژه 4-1 4-2 Cenral Pattern Generator
فصل پنجم- ياد گيري حركت و مدلهاي ارائه شده براي حركت 5-1 Motor Learning مدلهاي ارائه شده5-2
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
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
HUMAN MOTOR CONTROL SYSTEM
Overview
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
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
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...
MOTOR PLANS/PROGRAMS
complex movements & acts produced and controlled by set of commands to muscles, established before onset. Feedback on execution
THE CONTROL SYSTEMS VIEW
Machine design vocabulary: accuracy and speed criteria
Closed-loop and Open-loop ctrl mechanisms to optimize performance
CLOSED-LOOP CTRL MECHANISMS
continuous feedback from controlled system to controller (e.g. driving)
slow, sustained movements (ramp/smooth)
accuracy & flexibility at speed expense
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)
MOTION ANALYSIS & MEASUREMENT
photographic, computer graphic techniques
EMG (electromyography):
recording muscle electrical activity
fine needle electrodes (skin/muscle)
measure contraction involved in activity
EMG
EMG
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
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
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
MiddleLevel
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
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)
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]
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)