Exam #2 Flashcards
Generalized Motor Program (GMP)
- theory
- movements can be varied along certain dimensions
ex) slow/fast, louder/softer
Motor Program
prestructured set of movement commands that defines and shapes the movement
Open Loop Control
Input, Executive, Effector, Output
- no feedback or comparator
- no modifications while in progress
- inflexible
- most effective in stable environments
Open Loop Example
-traffic light continues to go even if an accident takes place
Motor Program determines
- which muscles to contract
- in what order
- when
- for how long
Practice helps build motor programs that are:
- more stable
- more precise
- longer-operating
- combo of those
Practice stored in
long term memory. must be retrieved and prepared for initiation during response programming
Most tasks are:
a mix of open and closed loop system
Reaction Time is longer with:
- more info to process
- more limbs must be coordinated
- duration of movements becomes longer
Startle Reaction
unexpected event causes a severe reaction
-accompanied by contraction of face/neck and protective movements of upper limbs
Startle Reaction motor program
- executive prepares motor program in advance
- signal released by executive is hastened
- executor may be bypassed altogether
Roles of Open Loop (muscles)
determine:
- forcefulness
- duration
- which ones contract
Roles of Open Loop
- organize degrees of freedom of muscles and joints
- initiate postural adjustments for support of action
- modulate reflexive pathways to ensure movement goal is met
Anticipatory Adjustments
motor system compensates before the movement is made
Generalized Motor Program Theory
- stored pattern
- stored program is adjusted at time of movement execution
- allows action to be changed slightly to meet environmental demands
invariant features of motor program
make a pattern appear the same time after time
surface features of a motor program
aspects that allow change in a movement
GMP Movement Production
- stimulus id phase
- response selection phase
- GMP retrieved from long term memory
- movement programming stage (motor program is prepared)
movement parameters
- speed of movement
- amplitude
- limb used
invariant features of a GMP
- relative timing (rhythm) (timing preserved)
- classes of movements (“throwing”)
GMP Parameters
- movement time
- movement amplitude
- effectors (movement can be modulated by using a different limb to produce same action)
Fitt’s Law
movement time is consistent whenever the ratio of the movement amplitude to target width remains constant
- MT increases as ratio of A to W increases
- long movements+wide targets = short movements + narrow targets
haste makes waste?
accuracy decreases as speed increases
speed accuracy trade off
people tend to give up speed in order to trade speed for accuracy