Information Processing in Motor Learning

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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
Cell Body
Dendrites receive message
Myelin sheath
Conductive Segment
Axon transmits message to terminal ending
Nodes of Ranvier
Terminal ending on muscle
sends off message to adjacent neuron
Transmissive Segment
Motor end plate
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Myelin sheath fatty covering or insulator
Skipping of the impulse allowing faster conduction
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Types of Neurons
Afferent neurons Sensory Carry signals to the
brain
Interneurons Originate and terminate in
CNS Connect afferents and efferents in CNS
CNS tissue cross-section
Efferent neurons Motor Carry signals from the
brain
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Types of Neurons cont.
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The Neurons Function
Receptive

• 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

Conductive
Transmissive
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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
Rest polarization
Membrane potential -70 mV
(mV) 50 0 -50 -100
Action Potential
40 mV
Resting Potential
Stimulus
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The Synapse and Synaptic Transmission
SYNAPSE
O
O
O
O
O
O
. .. . .. . ... . .
SYNAPTIC TRANSMISSION
O
O
O
O

• Differ in terms of
• Neurotransmitter used (e.g., acetylcholine or
  Ach)
• General function (e.g., inhibitory vs.excitatory)

NEUROTRANSMITTER
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The Synapse and Synaptic Transmission

• 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

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Indication of Strength of stimulus
STIMULUS
Refractory Period
Absolute
Relative
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Information Processing and Making Decisions
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Input
The Human
Output
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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

PERCEPTION
SENSATION
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Response-Selection Stage

• Translation from perception to a response in the
  form of a motor program

MP 13498
MP 00333
MP 04567
MP 09564
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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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• Central Processing System Functions
• Perception
• Decision making
• Data storage and coding
• Transition to motor program

• Sensory Receptors
• Ears
• Eyes
• Proprioceptors
• Vestibular system
• Etc.

• Effector System
• Biceps
• Quadriceps
• Abdominals
• Latissimus dorsi

• Output
• Pivot
• Dribble
• Jump
• Shot
• Pass

• Coaching Instructions
• Watch the opponent
• Feel the ball
• Keep balanced
• Listen to teammates

• 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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Error
Input
Senses
Correction
Perception Stimulus Identification
Comparator (Reference system)
CNS Executive The stages of information processing
Response Selection and Programming
Response Execution
PNS Effector The motor program and motor system
Motor Program
Proprioceptive Feedback
Muscles
Output Environment
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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STIMULUS
EXECUTIVE
EFFECTOR

• Chooses motor program
• Relays instruction

• Carries out specific instructions automatically

No Feedback
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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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Sensory Receptors Relay
Sensory Input Quality
Information Processing
Arousal and Psychological Readiness
Reaction Time
Ability to Anticipate
Capacity to Concentrate