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Sport Books Publisher 1
Information Processing in Motor Learning
Chapter 17
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Outline
Structure and function of the nervous system
Information processing and making decisions
Feedback in movement control
Factors affecting information processing
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Structure and Function of the Nervous System
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CNS
Control center
PNS
Connects CNS with the rest of
the body
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The Neuron and Its Function
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Neuron
Nerve cell
The fundamental functional and structural unit of the nervous system
Allows information to travel throughout the body to various destinations
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Receptive Segment
Transmissive Segment
Conductive Segment
Cell Body
Nodes of Ranvier
Myelin sheath
Motor end plate
Dendrites: receive message
Terminal ending on muscle: sends off message to adjacent neuron
Axon: transmits
message to terminal ending
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Myelin sheath: fatty covering or
insulator
Skipping of the impulse allowing faster
conduction
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Types of NeuronsAfferent neurons
Sensory
Carry signals to the brain
Efferent neurons
Motor
Carry signals from the brain
CNS tissue cross-section
Interneurons
Originate and terminate in CNS
Connect afferents and efferents in CNS
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Types of Neurons cont.
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The Neuron’s Function
Receptive segment (dendrites)– Receives continuous synaptic input
(chemical) from other neurons
Conductive segment (axon)– Conduction of neural information in the
form of nerve impulse (electrical)
Transmissive segment (axon terminals)– Converts electrical nerve impulse to
chemical form (neurotransmitter) and sends it off to synapse
Receptive
Transmissive
Conductive
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Neural Impulses Transport the information necessary for all activities
we carry out The language of the nervous system Relay of impulse within neuron:
Rest: polarization
Stimulus: depolarization
Membrane potential = -70 mV
Rest: polarization
Action Potential
Resting Potential
Stimulus
(mV)
+50
0
-50
-100
+40 mV
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The Synapse and Synaptic Transmission
OO OOO O
OO
OO
SYNAPSE
SYNAPTIC TRANSMISSION
•Differ in terms of :
•Neurotransmitter used (e.g., acetylcholine or Ach)
•General function (e.g., inhibitory vs.excitatory)
. : :.. …. …… …..:: : .
: .:.;. . .
NEUROTRANSMITTER
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“All-or-none” law– Synaptic transmission causes action potential when
its strength is above a minimum threshold level
– Below threshold level = NO action potential
– Action potential is always the same intensity regardless of the strength of synaptic transmission above the threshold level
– Action potential intensity remains constant along the nerve fibre
The Synapse and Synaptic Transmission
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Indication of Strength of stimulus
Refractory Period
ST
IMU
LU
S
Absolute Relative
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Information Processing and Making Decisions
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Input
Output
The Human
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Information-Processing Stages
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Stimulus-Identification Stage
•Sensing environmental information
•Exteroceptors
•Proprioceptors
•Representation of stimulus and its nature
SENSATION PERCEPTIO
N
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Response-Selection Stage •Translation from perception to a response in the form of a motor program
MP 09564
MP 00333
MP 04567
MP 13498
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Response-Programming Stage
•Organizing the selected movement
•Retrieve motor program
•Command correct muscles
•Choose appropriate force
•Choose appropriate timing, etc.Efferent nerves
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Feedback in Movement Control
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As we execute movements, the receptors in our bodies continually update the CNS about the nature of our actions
The efficiency of motor control by the information-processing system depends on feedback
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Coaching Instructions
•Watch the opponent
•Feel the ball
•Keep balanced
•Listen to teammates
Sensory Receptors
•Ears
•Eyes
•Proprioceptors
•Vestibular system
•Etc.
Central Processing
System Functions
•Perception
•Decision making
•Data storage and coding
•Transition to motor program
Effector System
•Biceps
•Quadriceps
•Abdominals
•Latissimus dorsi
Output
•Pivot
•Dribble
•Jump
•Shot
•Pass
Exteroceptive Feedback
•Error information
•Motivate
•Reinforce
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Closed-Loop Control
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Follows the idea that movements may be planned and adjusted by feedback even during a movement
This general closed-loop control process is self-regulating and will continue to maintain the desired movement of the performer
Key elements:– Feedback– Error detection– Error correction
Analogy: thermostat
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Input
Perception Stimulus
Identification
Senses
Response Selection and Programming
Response Execution
Motor Program
Muscles
Output Environment
Comparator (Reference
system)CNS
Executive
The stages of information processing
PNS Effector
The motor program and motor system
Error
Proprioceptive Feedback
Correction
Exteroceptive Feedback
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Advantages of the Closed-Loop System
New skills Activities requiring
precision and accuracy Allows adjustment
according to the situation Adds versatility to
movements
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Disadvantages of the Closed-Loop System
Rapid, discrete actions do not properly fall under closed-loop control
Demands attention and time– Feedback must pass through the
processing stage
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Open-Loop Control
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Describes control of automatic actions
Motor program defines the details of skilled action before the movement begins and without the influence of peripheral feedback
Movements may be structured in advance, enabling them to run off automatically when initiated
Two main components:– The executive– The effector
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•Chooses motor program
•Relays instruction
•Carries out specific instructions automatically
EXECUTIVE EFFECTOR
No Feedback
STIMULUS
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Advantages of the Open-Loop System
Fast and forceful movements can be produced without extensive conscious control
Attention can de diverted to other responses
Does not demand as much time because there is no feedback
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Disadvantages of the Open-Loop System
Not as effective in unstable and less predictable situations– Movements may not be determined
effectively in advance
Not effective in precise and complex actions
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Factors Affecting Information Processing
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Information Processing
Sensory Input Quality
Sensory Receptors
Relay
Reaction Time
Ability to Anticipate
Capacity to Concentrate
Arousal and Psychological
Readiness