Lecture 22 - Short and Long-Loop reflexes and control of sensory feedback

Question 1

How long do short-latency responses take?

Answer 1

20-50ms

Question 2

How long do long latency responses take?

Answer 2

50-105ms

Question 3

How long do voluntary responses take?

Answer 3

120+ ms

Question 4

Where are SLR’s processed?

Answer 4

Spinal cord

Question 5

Where are LLRs processed?

Answer 5

Brain

Question 6

Where are voluntary VOLs processed?

Answer 6

Brain

Question 7

What type of feedback is involved in SLRs?

Answer 7

spinal proprioceptive

Question 8

What type of feedback is involved in LLRs?

Answer 8

Spinal and cortical propriceptive feeback

Question 9

What type of feedback is involved in VOLs?

Answer 9

spinal, cortical proprioceptive and visual feedback

Question 10

What is an example of a SLR?

Answer 10

knee jerk relfex (monosynaptics stretch reflex)

Question 11

What are 2 properties of SLRs?

Answer 11

1. SLR scale with background muscle activity (Henmans size principle)
2. SLR scale with rate and amount of muscle stretch (more APS fired with larger stretch of muscle spindle)

Question 12

Is LLR polysynaptic or monosynaptic?

Answer 12

polysynaptic

Question 13

What are some other names for LLR?

Answer 13

• long loop
• long latency
• transcortical

Question 14

What type of feedback look do LLRs involve?

Answer 14

transcortical feedback loops

Question 15

Which reflex does goal directed processing?

Answer 15

LLR

Question 16

What do LLRs depend on?

Answer 16

The goal of the task

Question 17

Behavioural task of keeping hand in target

What is the SLR mostly driven by?

With the exception of the largest target

Answer 17

The rate and amout of motion caused by the perturbation

Question 18

Behavioural task of keeping hand in target

LLR annd VOL responses the same mechanical perturbation are inversly proportional to what?

Answer 18

Size of the target

Question 19

Behavioural task of keeping hand in target

Does the larger or smaller target have the smallest stretch response?

Answer 19

largest (lower accuracy demands, don’t need to ‘work as hard’ to keep hand in target

Question 20

Behavioural task of keeping hand in target

What is the desired state in this example?

Answer 20

To keep arm in a fixed target (goal of the task)

Question 21

Behavioural task of keeping hand in target

What is the motor plan in this example?

Answer 21

maintaining arm in target

Question 22

Behavioural task of keeping hand in target

What is the motor command in this example?

Answer 22

Activity in limb motor circuits (cortical or subcortical) to maintain the hand in the target

Question 23

What is expected state?

Answer 23

intened or planned movement

Question 24

What is error?

Answer 24

the difference between the expected state and the actual state

Question 25

What does the error signal do?

Answer 25

Used to adjust ongoing movement

Question 26

What is the feedback control system?

Answer 26

movement control mechanism that uses sensory feedback to detetc errors and correct voluntary motor actions

Question 27

What is a comparator? What is the comparorator in the feedback control system?

Answer 27

Comparator compares the actual and expected state of the body

the brain

Question 28

What is the effector?

Answer 28

the component of the peripheral motor system that generates the desired motor response

Question 28

Summarize SLRs.

Answer 28

They allow rapid stimulus dependent responses to a mechanical perturbation

Question 29

Summarize LLRs.

Answer 29

slower, polysynaptic responses that enable rapid, task-dependent control of sensory feedback to support voluntary motor actions

Question 30

Are SLRs or LLRs faster?

Answer 30

SLRs