Alternative motor control theories

Question 1

Describe a mechanically stable system

Answer 1

• Can it look like complex control is being used when it is not?
  
  • Control distributed to responses of mechanics of the system
  • The most organised state is the lowest energy state - redistribution of energy makes all the metronomes become in sink(organises itself)

Question 2

What are some implications of a mechanically stable system?

Answer 2

• Output should be exact same thing - but isn’t because of errors
  
  • Noise in MP so need to cope and find different ways to function with it
  • Nerves fire when there is a membrane potential imbalance - slightly dependable of the thermo-variances in cells
  • Most things that look like noise are not, just complex and difficult to spot differences

Question 3

How do motor programs work in a complex world?

Answer 3

• Not all complex motion may be due to neural control
• Not all complex motion even if neural may be brains
• We need to cope with movement and noise but is it all complex and clever control?
• Dynamical Systems(changing), area of maths
• Time dependence of points in space

Question 4

Name some underlying rules of dynamical systems

Answer 4

Nonlinear
Fractals
Chaos
Emergence
Constraints
Self-organising

Question 5

Define an attractor

Answer 5

Attractor - a set of states toward which a system tends to evolve
Can be simple to very complex

Question 6

Describe the limit cycle:

Answer 6

• Pendulum example with constant energy input per unit time to offset losses in the system also can stabilise it
• Lets say losses proportional to amplitude squared
• Constant energy in of 16 and stable with amplitude 4
• Slow the pendulum by grabbing it briefly amp ↓ 3
• Now energy loss is 9 but energy in 16 so amp ↑
• Speed it and amp ↑ 5 energy loss 25 and only 16 in, amp↓
  
  • Increase/decrease energy units, the pendulum will still return to is stable rate(restabilise)