Evolution of a Field of Study

1
Evolution of a Field of Study

• Understanding Movement
• Origins of the Field

2
Forms of Movement

• Genetically defined
• Self-differentiated throughout the species
• Reflexes
• Learned skills
• Not inherited
• Acquired through practice

3
Motor Control

• Study of postures and movements and the
  mechanisms that underlie them, regardless of the
  quality of the movement.
• Need to understand
• What is being controlled
• How the processes governing movement are
  organized
• CNS, PNS, Muscles, Joints, Sensory systems

4
Origins of the Field of Control

• Physiological Neurological Background
• Sherrington (1906-)
• Reflexes
• Reciprocal innervation Final common pathway
• Proprioception
• Bernstein (1930s and 40s)
• Originally published in Russian translated to
  English in 1967.
• Proved to be a catalyst for North American
  research
• Postwar Research
• Ergonomics, Human Factors

5
Resurrection of the Field

• Henry (1960s 70s)
• Trained many Ph.D.s and is considered the
  father of motor behavior
• Adams (1971)
• First Theory of motor learning
• Closed-Loop Theory
• Schmidt (1975)
• Schema Theory (Learning Theory)
• Generalized Motor Program Theory (Control Theory)
• Turvey, Kelso, Kugler, Reed (1970s - )
• Dynamic Systems, (Control Theory)
• Perception and Action

6
Motor Control

• What is it that has to be controlled?
• 206 Bones
• 650 Muscles
• 100 Joints
• Some Muscles are multi-articular
• Each structure has different elastic properties
• To move successfully the CNS must understand the
  properties of each of these structures.

7
Motor Learning

• A set of internal processes that lead to a
  relatively permanent change in behavior
• It is not something that is readily observable
• It occurs as a function of practice and
  experience, not maturation, motivation, or
  training.

8
Behavioral Level of Analysis

• Typically we cannot see how the system functions
  internally.
• Goal of Control research
• Understand variables that determine motor
  performance and are important for learning and
  control.
• How these variables can be used to develop
  equipment, teach motor skills, and design rehab
  programs.

9
Important Interaction Impacting Control, Learning
Development
10
Next Week Ch. 2

• Classification of Behavior
• Based on the movements made
• Discrete, continuous, serial
• Based on the Attributes of the task
• Open, closed
• Measurement considerations
• Objectivity, Reliability, Validity
• Assessing error in movement
• CE, VE, E (RMSE), AE
• Reaction Time, Movement Time
• Kinematics relative absolute phasing

11
Methodology for Studying Motor Performance

• Classification of Motor Behavior
• Measuring Motor Behavior

12
Classification of Behavior

• Based on the movements that are made
• Discrete
• Recognized beginning and end point
• Continuous
• No recognized beginning or end point
• Serial
• A number of discrete tasks strung together with
  an inherent order parameter

13
Classification of Behavior

• Based on the perceptual attributes of the task.
• Open Skills
• Changing environment
• Movement planning affected?
• Closed Skills
• Stable environment
• Performance variability?
• Why should we approach these skills differently?

14
Measuring Motor Behavior

• Outcomes of the Movement
• Error
• Constant
• Variable
• Total Variability
• Absolute
• Speed
• Reaction time
• Movement time
• Movement magnitude

15
Measurement of Time and Speed

• Reaction Time
• Time between the onset of the stimulus and the
  beginning of the response.

16
Characteristics of Movements

• Kinematics
• Location
• Velocity
• Acceleration
• Coordination Kinematics
• Plotting two segments or joints against each
  other
• Control Kinematics
• Plotting two kinematic variables of interest

17
Measurement Devices

• Direct Method
• Goniometer, Potentiometer
• Indirect Method
• Video analysis, optoelectric
• EMG
• Patterns of activation
• Activation times
• Co-contraction?
• EEG
• Brain regions responsible for movement
• Mapping the brain

18
Next Class (Aug 27)

• Reading for next couple classes
• Latash Chapters 2 and 3
• pp. 219-226 Synaptic Integration (Kandel et al)
• Coming via email tonight

19
Lestienne Reading

• Will discuss the complexity of human movement
  that we discussed in class.
• Also discuss the techniques used to measure
  movement and its control
• Asks the question How is it that the CNS
  selects a set of muscles and joints to perform a
  movement
• Motor Equivalence

20
Lestienne Reading cont

• Mentions multiple theories briefly (not all by
  name)
• Force Control Model
• Motor Program
• Dynamic Systems
• Lamda Model
• States that any theory needs to be able to
  address the posture-movement problem
• Why when we move away from an initial posture do
  we not have resistance from posture stabilization
  mechanisms
• CNS Organizes using Frames of Reference (FR) or
  systems of coordinates
• Changes in one FR impacts all others involved
• CNS can manipulate the parameters of the FR and
  thereby guide motor actions (affordances)
• Movement laws
• Acceleration/deceleration Reciprocal and
  Coactivation Feedforward control
• Reflexes and Central Pattern Generators

21
Kandel et al., reading

• Synaptic Integration
• Excitatory and Inhibitory Signals
• Integrated into a single response
• At CNS impulses are grouped as a function of
  where they activate the neuron
• Understanding of how the neurons act and become
  activated

22
Latash Chapters

• Basic information on the structure and function
  of the nervous system
• Action Potentials
• Synaptic Transmission
• Summation of Signals
• Interaction of excitatory and Inhibitory
  Impulses.

23
Final Note

• What is it that goes on over the 49th parallel

24
Orthopedic Patient and EMG

• Patient using cane to walk
• Same patient with 15 body weight support

25
Phase Plane Trajectory - Control
26
Angle-Angle Diagrams - Coordination