Lecture 5

Question 1

what is open loop control in motor control

Answer 1

movement executive sends a command to the effectors, no use of sensory information to guide movement

Question 2

what is closed loop control in motor control

Answer 2

sensory information from the effectors is fed back to the executive to inform the control centre about the movement

the executive uses sensory information as a comparison tool to amend motor commands (if needed)

Question 3

what are the reflex theories of motor control

Answer 3

reflexes form the basis of all movements

complex movements > response chaining / reflex chaining

Question 4

who proposed that reflexes form the basis of all movements

Answer 4

Sherrington

Question 5

what are the limitations of reflex theories

Answer 5

• don’t allow for proactive action
• poor account for open loop control
• some movements dont require afferent input

Question 6

what do hierarchical theories of motor control assume

Answer 6

assumes all aspects of voluntary movement planning and execution are the sole responsibility of higher cortical centres

Question 7

what do hierarchical theories of motor control assume about lower CNS

Answer 7

more automatic actions

Question 8

what do hierarchical theories of motor control assume about higher CNS

Answer 8

voluntary actions

Question 9

what do hierarchical theories of motor control assume is the controller

Answer 9

cerebral cortex

Question 10

what are the limitations of hierarchical theories

Answer 10

Can not explain how direct perception works:

Cannot explain self organizing systems

Question 11

what is meant by can not explain how direct perception works ( limitations of hierarchical theories )

Answer 11

• Optical flow
• Affordances
• “time to contact”

Question 12

who are the two contributors to the dynamical / ecological theories of motor control

Answer 12

Gibson (1966) and Bernstein (1967)

Question 13

what are the three assumptions of the dynamical / ecological theories of motor control

Answer 13

• human movement control is complex and dynamic
• human perceptual motor system is capable of self organising via interacting constraints
• perception of affordances is direct via energy flows from environment

Question 14

what is perceptual motor landscape

Answer 14

a manifold of all the possible movement possibilities available to an individual

Question 15

what is self organisation

Answer 15

the natural tendency for the human perceptual motor system to settle into attractors

Question 16

what does order parameters mean

Answer 16

collective behaviour of the system’s many components e.g relative phase between body segments

Question 17

what are control parameters

Answer 17

a parameter of internal or external origin that when manipulated controls the system in a non specific fashion e.g frequency, velocity

Question 18

what is stability / instability

Answer 18

a qualitative state describing the tendency of a system to remain in a particular pattern of organisation or not

Question 19

what is hysteresis

Answer 19

the tendency to remain in the current basin of attraction as the control parameter (e.g velocity) is increased (or decreased)