Describe how a) the equilibrium point hypothesis and b) internal models of the motor system aid understanding of human movement control. Discuss the limitations of each approach.

Question 1

What is the Equilibrium Point Hypothesis (EPH)?

Answer 1

It suggests that movements are governed by the shift of muscles’ length and tension, or equilibrium points, rather than intricate neural signals specifying the details of each movement

Question 2

How the does CNS factor into EPH?

Answer 2

The CNS sets a control parameter associated with an equilibrium point and the movement occurs as a result of the physical characteristics of the muscles as they strive to reach this new equilibrium

Question 3

Why is EPH considered a simpler model for understanding motor control?

Answer 3

EPH reduces the need for the CNS to control each aspect of movement

Question 4

What is the main limitation of the EPH

Answer 4

It focuses mainly on single-joint movement, making it less applicable to more complex, multi-joint and coordinated movements that are characteristic of human activities

Question 5

What is the 2nd limitation to the EPH approach?

Answer 5

The EPH does not account for the influence of external factors, like gravity and inertia on movement. These can impact the biomechanics of movement and their omission represents a considerable limitation of this approach

Question 6

What is the Internal Models Approach?

Answer 6

It proposes that the brain maintains a model of the body’s dynamics and uses it to predict and control movement.

Question 7

What are Forward Models?

Answer 7

They predict the outcome of motor commands

Question 8

What are inverse models?

Answer 8

Which determine the necessary motor commands to obtain a desired outcome

Question 9

What is the benefit of the internal Models?

Answer 9

This approach enables the prediction and compensation of delays in the sensorimotor system and facilitates the fine-tuning of movements to accomplish tasks with precision

Question 10

What is the main limitation of the internal models ?

Answer 10

Maintaining and updating these models is complex, given the non-linear and time-varying nature of the body’s dynamics; this presents a significant computational challenge and can limit the applicability of this approach

Question 11

What is the 2nd limitation of the internal model?

Answer 11

It remains unclear how these models are acquired and updated thorugh learning and experience and how they are represented in the brain