Motor Loops_PL

Question 1

List the 2 ways movements are broke down

Answer 1

1. Open loop control (bottom up)
2. Closed loop control (top down)

Question 2

Describe the “loop”

Answer 2

The loop is a cycle or circuit of action and evaluation. If the loop is closed feedback becomes a critical part of the loop. If the loop is open feedback can only be applied to future action.

Question 3

Type of Loop: The instructions are structured in advance and are executed without regard to the effects that they may have on the environment

Answer 3

Open loop

Ex. like using a fire to try and keep a consistent temp in your house

Question 4

List the Key Features of Open Loop Control (3)

Answer 4

• RAPID, less than 150 ms
• CANNOT use sensory feedback to alter current movement
• PROGRAMMED movement

Question 5

Describe central pattern generators (CPGs) (2)

Answer 5

CPGs are a network of neurons in the SC that produce rhytmical movements in the limbs even when the brain is not receiving sensory feedback from the periphery

Flex/ext mm groups are alternately activated when the SC is stimulated

Question 6

List the important concepts about CPGs (6)

Answer 6

1. Prewired in SC
2. Turned on in various ways and continue until shut off
3. Patterns can me modified based on sensory input
4. Basic relfexes are still active and can influence CPG output
5. Reflexes are not stereotyped (reflex-reversal phenomenon)
6. The GOAL of movement is MAINTAINED

Question 7

Term: restructured set of central commands and capable of carrying out movement

Answer 7

Motor program

Question 8

List the evidence for the exists of motor programs (3)

Answer 8

• Some movements are performed faster than feedback can be processed
• Reaction time is longer for complex movements compared to simple movements
• Individuals who can’t receive sensory input can still perform some skilled movement

Question 9

List the 2 types of errors seen in motor programs

Answer 9

1. Program selection
2. Program execution

These errors occur b/c we can’t/don’t have a motor program for every possible situation

Question 10

Type of error: from a misperception of the environment

Answer 10

Program selection

Question 11

Type of error: from an unexpected difference or alteration in environment

Answer 11

Program execution

Question 12

Type of Loop: the system can recieve and process feedback information

Answer 12

Closed Loop Control

ex. Modern thermostat

Question 13

List the Key features of closed loop control (3)

Answer 13

• SLOW, 120-180, up to 250 ms
• FEEDBACK allows for online adjustment
• CONTINUOUS or longer movements

Question 14

Describe hierarchical levels of control

Answer 14

This concept of control adapts open loop control to allow for the know influence of sensory feedback

Question 15

List the 2 concerns with the concept of a motor program and what idea have they led to?

Answer 15

1. How does the brain store all these programs?
2. How do we produce the movemes that we have never done before?

Generalized motor programs (GMP)

Question 16

Describe how the GMP solves the concerns with motor progams

Answer 16

• They would have invariant features i.e. fixed features and actions that are identified as coming from that motor program
• They can be parameterized i.e. certain features of the template can be adjusted to meet the demand

Question 17

List the invariant features of the GMP (3)

Answer 17

1. order of events
2. relative timing of components of movement (duration can change but percentage by component is the same)
3. relative force of components

Question 18

List the parameters of GMP that can be altered (3)

Answer 18

• Duration of movement
• Overall force that will be required
• Selection of mm to complete the movement

Question 19

List the 3 groups of sensory information

Answer 19

1. interoceptors (i.e. hunger)
2. Exteroceptors (i.e. vision, audition, smell)
3. Proprioceptors (i.e. vision, audition, vesitbular system, mm/joint/cutaneous receptors)

Question 20

List the key features of reflexive corrections (4)

Answer 20

• VERY rapid, as little as 30 ms
• May NOT require conscious attention
• Mediated at spinal level
• 2 kinds: myotatic and long loop