Motor Control Theories Lecture 7 PDF

Review from last class Fun fact: It takes less time for an orbiting satellite to send a signal to earth than for an elephant’s spinal cord to send a signal to its lower leg This nervous system delay is a major limiting factor for use of sensory feedback to guide movement Think...

Review from last class Fun fact: It takes less time for an orbiting satellite to send a signal to earth than for an elephant’s spinal cord to send a signal to its lower leg This nervous system delay is a major limiting factor for use of sensory feedback to guide movement Thinking about motor control systems and theories from last class, how do elephants move so well? Prediction! 1 https://www.sfu.ca/sfunews/stories/2018/08/not-so-fas  KIN 280 – Motor control and Learning Motor Control Theories Faculty of Kinesiology and Health Studies University of Regina, Regina, SK January 20, 2025 2 Motor Control Theories 3 Motor Control Theories Learning Outcomes: Describe a primary difference between Motor Program Theory and a Dynamical Systems Theory of motor control Define the following terms associated with Dynamical Systems Theory Stability, attractors, phase transition, order and control parameters, self-organization Discuss how both Motor Program and Dynamical Systems Theory explain relative time characteristics of human walking and running 4  Motor Control Theories 1. Identify task and “_____ __ _______”. Rank Responses 1 2 3 4 5 6 5  Motor Control Theories 2. Retrieve the appropriate “___________ _____ _______” from memory. Rank Responses 1 2 3 4 5 6 6  Motor Control Theories 3. Add the “________-________ _________” to the GMP depending on performance characteristics (based on schema). Rank Responses 1 2 3 4 5 6 7 Motor Control Theories Dynamical Systems Theory: An approach to describing and explaining the control of coordinated movement that emphasizes the role of information in the environment and the dynamic properties of the body and limbs De-emphasizes memory Multidisciplinary perspective combining physics, biology, chemistry and mathematics 8 Motor Control Theories Dynamical Systems Theory: Non-linear dynamics – behavioural changes over www.ibtimes.com time do not follow a continuous, linear progression Examples of complex, non- linear dynamic systems – weather, animal populations, stock markets www.businessinsider.com 9 Motor Control Theories Dynamical Systems Theory: Non-linear systems exhibit “chaos”; predictable linear behaviour can become chaotic (unpredictable) in certain circumstances Example: Determinist, periodic system (linear) 1__2__3__4__5__... Non-linear system is determinist and aperiodic There are rules at each step, but the relationship between any two steps is different than any other There are no repeated patterns Non-determinist, aperiodic system has NO rules, it is random 10 Motor Control Theories Dynamical Systems Theory: Non-linear systems exhibit “chaos”; predictable linear behaviour can become chaotic (unpredictable) in certain circumstances Water wheel example – https://www.youtube.com/results?search_ query=Robert+Sapolsky+water+wheel Other examples: At high speeds the airflow over a jet’s wings can change from laminar (smooth) to turbulent, thereby affecting lift and drag At high temperature (100 C) water boils 11 Motor Control Theories Dynamical Systems Theory: Activity - Put your hands in front of you on the table in a fist (pinky down on table), then stick your index fingers out Very slowly, move your index fingers back and forth together in the pattern of windshield wipers (left-extend, right flex then left-flex, right- extend) – anti-phase pattern Position Position 1 2 Extende Flexed Flexed Extende Go faster d and faster while looking straight ahead, not atdyour fingers After 20 s, look down at your finger movements. What do you see? 12 Motor Control Theories Dynamical Systems Theory: Typically, the finger movement pattern transitions from “anti-phase” to “in-phase” Spontaneous change in coordination is a non-linear Position change in Position movement1 behaviour 2 Extende Extende Flexed Flexed d d 13 Motor Control Theories Dynamical Systems Theory: Stability – a behavioural steady state of a system (e.g., anti-phase or in- phase finger movements) Attractors – stable behavioural states (e.g., at 3 mi/hr people adopt a walking coordination gait, at 10 mi/hr people adopt a running coordination gait), attractor states in human movement tend to be energy efficient Phase transition – point at which instability characterizes the system Self-organization – given a certain set of conditions, stable patterns of behaviour emerge (e.g., crowd behaviour, school of fish, flock of birds, group of muscles) Order parameters – functionally specific variables that define the overall behaviour of a system Control parameters – the variable that when increased or decreased influences the stability of the system 14  Motor Control Theories Position Position 1 2 At low frequency, Finger joint angle anti-phase pattern relationship is an order is stable parameter The anti-phase Movement frequency is pattern is an a control parameter attractor state Extende Flexed Flexed Extende d d The chaotic period of no Position Position coordination pattern is 1 2 the phase transition At high frequency, in-phase pattern is stable Settling on a new pattern is self- The in-phase organization pattern is another Flexed Flexed attractor state Extende Extende 15 d d Motor Control Theories Dynamical Systems Theory: Stable patterns of limb movement (coordination) self-organize given certain structural, environmental and task conditions This theory de-emphasizes the role of the CNS, memory Instead of solving a substantial number of control problems, the CNS just adapts and works with self-organizing patterns Research is needed to extract the “rules” of self-organization from the patterns observed in human movement 16  Motor Control Theories Walking and running: There is a certain speed at which you can no longer walk, you must run The relative timing of limb movements is different E1 – Knee extension to heel strike Relative time E2 – Heel strike to max percentage of knee-angle flexion total step cycle E3 – max knee-angle time for each step flexion to toe-off cycle phase F – toe-off to knee extension How can this be explained by Motor Program Theory and Dynamical Systems Theory? 17  Motor Control Theories How can this be explained by Motor Program Theory and Dynamical Systems Theory? E1 – Knee extension to heel strike Relative time E2 – Heel strike to max percentage of knee-angle flexion total step cycle E3 – max knee-angle time for each step flexion to toe-off cycle phase F – toe-off to knee extension Motor Program Theory – 1) Relative timing of step cycle is invariant feature 2) Total duration of step cycle is movement-specific parameter 3) Running uses a different GMP (it is within a different “class of actions”) 18  Motor Control Theories How can this be explained by Motor Program Theory and Dynamical Systems Theory? E1 – Knee extension to heel strike Relative time E2 – Heel strike to max percentage of knee-angle flexion total step cycle E3 – max knee-angle time for each step flexion to toe-off cycle phase F – toe-off to knee extension Dynamical Systems Theory – 1) Relative timing is an order parameter 2) Gait speed is a control parameter 3) Transition from walking to running is a phase transition 4) System “self-organizes” into new relative timing pattern (stable, attractor state) 19  Motor Control Theories Can knowing about motor control theories really inform practical work? 20 Motor Control Theories Summary of Learning Outcomes: Describe a primary difference between Motor Program Theory and a Dynamical Systems Theory of motor control Motor Program Theory is highly dependent on memory-based representations, Dynamical Systems Theory de-emphasizes the role of the CNS Define the following terms associated with Dynamical Systems Theory Stability, attractors, phase transition, order and control parameters, self-organization Discuss how both Motor Program and Dynamical Systems Theory explain relative time characteristics of human walking and running Different GMPs vs phase transitions between attractor states KEY POINT: Multiple theories explain many characteristics of movement, but no single theory explains everything 21 Motor Control Theories Wednesday January 22 – Lab 1/2 work class 22