EXS 313 Exam 2

Question 1

open-loop control

Answer 1

desired state (feedforward)
executive system (brain, information processing, decision-making)
effector system (spinal cord, limbs, nerves, movement, implementation)
actual state

a way to control fast movements that are produced without the use of movement produced feedback for adjustment during movement

Question 2

closed-loop control

Answer 2

desired state (feedforward)
executive system (brain, information processing, decision-making)
expected state (goes to the comparator)
effector system (spinal cord, limbs, nerves, movement, implementation)
actual state (goes to the comparator)
comparator (evaluate/compare if our actual action matched our desired action)
error (if there is an error score of 0, you continue without changing commands)

this model relies on feedback
a process of movement control that usually pertains to slow, continuous movements or automatic movement adjustments (reflexes)

Question 3

point-of-no-return

Answer 3

the point in a skill where you can no longer make adjustments or corrections due to time constraints

Question 4

deafferentation research findings

Answer 4

the surgical procedure to severe a bundle of nerves to prevent nerve impulses from reaching the spinal cord (no sensory feedback)
- fast actions and locomotion were fine
- tasks requiring closed-loop control were not possible (no fine motor tasks)

finding: certain motions are pre-programmed, so we don’t need sensory feedback (similar to open-loop control)

Question 5

reflexes

Answer 5

rapid movements
example) knee-jerk response when the patella tendon is stimulated (M1 reflex)

M1 reflexes: is low level and does not involve voluntary control
30-50 ms (very fast)

M2 reflexes: slightly more voluntary and longer
50-80 ms

Question 6

reflexes in a closed loop model

Answer 6

a process of movement control that usually pertains to slow, continuous movements or automatic movement adjustments

Question 7

inherent feedback

Answer 7

the feedback that comes naturally
example) visually seeing the error

Question 8

augmented feedback

Answer 8

the feedback that is given by an outside source
example) coach, newspaper article, PT clinic device, stopwatch, video replay

Question 9

optical array

Answer 9

the ray of light reflected by the objects in your vision, hit the eyes at certain angles
- light is bouncing off of all objects in your visual field (environment), making them visible to you

Question 10

optical flow

Answer 10

change in light information (change in array) as you move through the environment, “flow of light” across the retina
important information: time until contact, trajectory

Question 11

dorsal vision system

Answer 11

entire visual field, control of movement, nonconscious, good in low light, track motion, fast
processed at motor intent level

Question 12

ventral vision system

Answer 12

focal system
central field only, ID objected, conscious, degraded by low light, slow
processed as exteroceptive feedback

Question 13

quiet eye movements

Answer 13

duration is often related to skill/performance
longer quiet eye = more skillful

Question 14

saccadic eye movements

Answer 14

discrete, fast, quick, information received during fixations, quiet eye; jumping tracking
example) a car drives by really fast, but you were able to read the license plate during a saccade/fixation

Question 15

smooth pursuit eye movement

Answer 15

slow, precise; pick up details on slow-moving or still objects
smooth tracking

Question 16

generalized motor program theory

Answer 16

a program that governs a class of similar movements (a basic structure)
pulls parameters and adjusts the time of movement to meet environmental demands

Question 17

invariant features

Answer 17

make the movement appear the same, time after time
- order of movement components
- relative timing
- temporal structure/rhythm

Question 18

parameters

Answer 18

the way a movement is executed (variations)
example) writing slow or fast, large or small

Question 19

novelty problem

Answer 19

we never repeat the same movement twice

Question 20

storage problem

Answer 20

too many things to remember

Question 21

temporal accuracy

Answer 21

timing

Question 22

spatial accuracy

Answer 22

location (space)

Question 23

index of difficulty

Answer 23

defines the difficulty of targets based on a combination of amplitude and width

Question 24

single motor program view

Answer 24

one motor program used, flow through the bottleneck quickly

Question 25

Why do we see the speed-accuracy tradeoff?

Answer 25

SATO
the faster a movement or skill is produced, the less accurate

Question 26

What are some exceptions to the speed-accuracy tradeoff?

Answer 26

very rapid or forcefull movements (near max) and skills where timing is critical (temporal accuracy)

Question 27

roles of afferent nerves

Answer 27

nerves that carry signals toward the central nervous system from the periphery

Question 28

roles of efferent nerves

Answer 28

nerves that carry signals away from the central nervous system to the periphery to initiate an action

Question 29

exteroception

Answer 29

sensory information about the state of the environment or objects in the environment
example) vision, steepness of stairs, closeness of jet (based on sound)

Question 30

proprioception

Answer 30

information about the state of the body
example) how our muscles feel while climbing the stairs

Question 31

vestibular apparatus

Answer 31

located in the inner ear; provides information about balance and the body’s orientation

proprioception

Question 32

joint receptors

Answer 32

located in joint capsules; provide information about extreme joint positions

proprioception

Question 33

muscle spindles

Answer 33

located inside the muscle belly; provide information about extreme muscular stretch

proprioception

Question 34

cutaneous receptors

Answer 34

located in the skin; provide information about pressure, heat, texture, etc.

proprioception

Question 35

feedforward

Answer 35

represents anticipated sensory consequences which help us plan actions
- View this as an internal picture of what an action will look like

Question 36

closed-loop control notes

Answer 36

feedback is required and is generated by movement and used during movement
movement must last long enough for the performer to use feedback during exertion (must be long enough to have a reaction time, movement time, and together as a response time)
examples) balancing activities, the game Operation

Question 37

closed-loop control limitations

Answer 37

time for information processing and correction from error score
tracking tasks: 3 corrections/second —- ~333 ms for IP

Question 38

open-loop control examples

Answer 38

swing a golf club, power clean lift, breaking a board in karate, a chiropractic adjustment

Question 39

dorsal vision system

Answer 39

entire visual field, control of movement, nonconscious, good in low light, track motion, fast
processed at the motor intent level

Question 40

motor program

Answer 40

the blueprint, pre-planned recipe for learned movements
roles:
- to define and issue commands to muscles (when, force, how long, which muscles)
- to organize degrees of freedom into a single unit
to specify and initiate preliminary postural adjustments
to modulate reflex pathways to ensure movement is achieved

Question 41

reflex reversal phenomenon

Answer 41

stimulus of top of foot
same stimulus bit the reflex is reversed to maintain balance

Question 42

closed-loop control examples

Answer 42

walking on a treadmill, riding a bicycle, stitching up a wound, sprinting, active release (manual massage technique)

Question 43

closed-loop control examples

Answer 43

walking on a treadmill, riding a bicycle, stitching up a wound, sprinting, active release (manual massage technique)

Question 44

centralized pattern generator

Answer 44

genetically defined actions such as chewing, locomotion, and breathing
we are born with these natural movement skills for survival
left/right triggered signals such as walking pattern