970 likes | 1.35k Vues
Chapter 5. Motor Control Theories. Information flow and action control. Feedback guided control or closed-loop control. Information flow and action control. Planned control or open-loop control . Identify the flow of information controlling the action. The give and take of information flow.
E N D
Chapter 5 Motor Control Theories
Information flow and action control • Feedback guided control or closed-loop control
Information flow and action control • Planned control or open-loop control
The give and take of information flow • Is one type of control better than the other? • Is one type of control better for discrete, serial, or continuous skills? • Is one type of control better for an open or closed environment or skill? • What is an advantage of closed-loop control? • What is an advantage of open-loop control?
Why are theories important? • Theories provide a framework for understanding phenomena • Theories provide a framework for understanding outcomes • Theories provide a framework for developing applications
Theories of Action or Motor Control • At the most general level: What do motor control/learning theories need to explain? • Coordination • Degrees of freedom and DF problem • Constraints
Theories of Action or Motor Control • At the specific level of events or actions: how have motor control/learning theories attempted to explain things? • Coordination: What are the controlled variables? • How is the action controlled? • How are DF organized or constrained to reduce the problem of control and/or coordination?
Motor program theories • Central representation • Selection rules • How is a program assembled?
Schmidt’s Schema theory: GMP • Generalized motor program (GMP) • What type of actions was the theory designed to explain?
Schmidt’s Schema Theory:MRS • Motor response schema (MRS) • Examples of GMPs and parameters
Writing your name • Serial action
Writing your name • What DF can be used to write your name?
Locomotion: stride analysis Stance Swing
1500 60 50 1200 Step cycle duration (ms) 40 Percent of step cycle 30 900 20 walking running 600 10 3 4 5 6 8 9 10 11 12 Speed of locomotion (km/hr) walking running 0 3 4 5 6 8 9 10 11 12 Speed of locomotion (km/hr) Rhythmic actions and GMPs
Dynamic pattern theory: Key concepts • Self-organization • Attractor • Order parameter • Coordinative structure
o 0 o 1 8 0 A B D A B D L e f t L e f t F i n g e r F i n g e r A D D A D D A B D A B D R i g h t R i g h t F i n g e r F i n g e r A D D A D D Dynamic patterns: self-organization in human motor skills
Right finger Left finger Dynamic patterns: phase transition between behavioral patterns A B D A D D 1.5 Hz 1.75 Hz 2.0 Hz 2.5 Hz Ab RH Ad transition Ab LH Ad Ab LH Ad
1 8 0 6 0 1 6 0 ) ) g g 5 0 1 4 0 e e d d ( ( e D 1 2 0 s S 4 0 a h e s P 1 0 0 a e h v 3 0 P i 8 0 t a e l v e i t R 6 0 a 2 0 l n e a R e 4 0 M 1 0 2 0 0 0 1 . 5 2 . 0 3 . 0 2 . 5 D r i v i n g f r e q u e n c y ( H z ) Dynamic patterns: compare in-phase and anti-phase
Left-H. Right-H. Bimanual coordination: from cortex to limbs • Is there a transition in the brain? • Where does the instability (loss of stability) come from?
1 . 5 H z 1 . 7 5 H z 2 . 0 H z 2 . 2 5 H z A B D A D D P o s i t i o n o f R i g h t i n d e x f i n g e r P o s i t i o n o f L e f t i n d e x f i n g e r 5 0 0 m s Neural crosstalk: from muscle to limbs
Interpersonal coordination skills • Schmidt et al. (1990)
180 45 Standard deviation (VE) Mean relative phase 150 35 25 90 15 30 5 Increasing speed Tr Increasing speed Increasing speed Tr Increasing speed Interpersonal dynamics • What happened when movement frequency was increased?
Perceptual threshold • Smooth pursuit eye movements
More emergent phenomenon: walking and objects • Perception-action coupling
Chapter 6 Touch, Proprioception and Vision
Perception-action • All actions require a transfer of perceptual information into motor commands • Closed-loop control • Open-loop control
Tactile sensations • Mechanoreceptors • Role in action control (closer look pg. 111)
Proprioception: limb and body position and movement • Muscle spindles • Golgi-tendon organs (GTO) • Joint receptors
Deafferentation: • Surgical • Temporary • Neuropathy • Tendon vibration
Error (cm) Sensory neuropathy: loss of proprioception • Blouin et al. (1993) • Independent variables • Dependent variable
Sensory neuropathy: loss of tactile and proprioception • Bimanual coordination (Spencer et al. 2005) • Draw two circles
X-displacement Sensory neuropathy: loss of proprioception • Patients Vision of:
Rubber hand Illusion • See papers by • M. Botvinick and J. Cohen (1998) • Ehrsson et al. (2004) Figure 3.49
Vestibular system: head and body position and movement • semi-circular canals • otolith organs • balance
Vestibular and visual systems: feedback control and balance • Task: Maintain balance on a moving support surface - 12 cm • Kinematics: video cameras • Platform speed (Hz): • Feedback conditions
forward backward Eyes open: Frequency 0.1 Hz anterior 10 A/P Disp (cm) 0 posterior 10 secs -10 time trunk platform forward backward 10 A/P Disp. (cm) 0 -10 Vestibular loss: postural responses • Buchanan and Horak (1999); Buchanan and Horak (2002)
anterior 10 secs 2 secs posterior trunk platform Platform speed: postural responses • Postural behavior
Questions: • 1) How did the loss of vestibular information influence balance and posture? • 2) How did platform velocity affect balance and posture? • 3) What did visual information contribute to balance control?
Vision and motor control • Central vision • Peripheral vision • Visual field
Vision and motor control • Vision-for-action (dorsal stream) • Vision-for-perception (ventral stream) • Two distinct neural pathways
Vision and motor control • Reaching and grasping • Describe a cup • Reach for a cup
Vision and motor control • Optical field • Optical flow
Contact with objects:stationary and non-stationary • Estimate contact • Braking a car • Time to contact with an object (tau) STOP