Module 5 Flashcards
Define coordination.
Mastering the many degrees of freedom involved in a particular movement. Reducing the number of independent variables to be controlled.
Define coordination dynamics.
The characterization of coordinator terms such as temporal, spatial, and functional patterns of organization.
Which experiments prove that we have bimanual control of our limbs, rather than 2 unimanual systems?
Longer/shorter target reaching: when L/R hands are doing different tasks, the movements finish at the same time. The default was to synchronize the timing. If we had full independent control, the shorter reach would finish first.
Hurdle task: L/R hands had the same reach length, but one hand had to reach over a hurdle. The hand path results were that both hands acted as if they were supposed to clear the hurdle, even though it was present for only one hand.
Explain Von Holst’s Maintenance tendency of the labrus fish.
When the pectoral fin was blocked from moving, the dorsal fin started moving at its own, different tempo. The dorsal fin prefers to move at its own rhythm when left on its own.
Explain Von Holst’s Magnet Effect of the labrus fish.
When the pectoral fin was released, the dorsal fin was pulled back into the synchronized rhythm. AKA entrainment dynamics.
What are Von Holst’s 3 rules for coordination?
- Only a few patterns can be easily performed, and these patterns are distinguished by their stability.
- Stable patterns are maintained until a critical limiting condition is reached, then transition to another pattern can occur.
- There is a tendency towards increasingly stable patterns - we never go to more unstable ones.
What is the evidence for being unable to hold unstable patterns (Kelso)?
When manipulating movement speed…
In-phase patterns (i.e. both fingers doing a motion in the same direction) can be maintained easily. Anti-phase patterns (i.e. each finger is moving in a different direction) transition into an in-phase pattern and cannot be maintained.
What is the difference between the egocentric principle and the allocentric principle?
Egocentric: pattern stability is dependent on symmetrical activation of homologous muscles.
Allocentric: pattern stability is dependent on the symmetrical direction of movement.
Explain the evidence for the egocentric principle (Carson et al.)
While probing with TMS to measure cortical excitability and the H-reflex to measure spinal excitability, a stationary right hand was activated while the left hand performed a movement.
Explain the evidence for the allocentric principle (Baldissera et al.)
In non-homologous muscle preparation (i.e. moving the hand and the foot at the same time), moving in the same direction is easier/more in synchronized.
When the arm is stationary and the foot is moving, excitability of the FCR muscle increases depending on which leg muscle is active (soleus or tibialis anterior). For example, a pronated arm’s FCR will be more activated when the soleus muscle is moving, as plantar flexion and wrist flexion move in the same direction.
