Week 7 - Info Processing in Motor Learning and Control

Question 1

What is the premise of the information processing model?

Answer 1

Human information processing works like a computer.

1. Sensory systems take in info from external source.
2. Perceptual processes lead to some form of symbolic representation of environmental and task information.
3. Info is stored with existing memory stores and processed for meaning.
4. Speed of processing determines output.
5. Information output results in various kinds and qualities of movement.

Question 2

What are the 3 stages of movement planning?

Answer 2

1. stimulus identification (perception)
2. response selection (decision making)
3. response execution

Ex. 1. icy sidewalk 2. take smaller steps 3. decrease push-off in gait

Question 3

What occurs during stimulus identification?

Answer 3

• Receptors transform stimuli into coding impulses (frequency/temporal/population coding)
• Perception –> meaning is assigned to stimuli (pattern recognition, stimulus features, or predictive capabilities)

Question 4

What happens during response selection?

Answer 4

compare choices from existing motor memory stores

Question 5

What happens during response execution?

Answer 5

• CNS may organize muscles to perform the task, temporal onset of muscle action, and/or muscle contraction force & duration
• Output is organized movement response

Question 6

What is the most common measure of cognitive performance/information processing with movement?

Answer 6

reaction time

Question 7

Why do we use reaction time?

Answer 7

Can be used to infer multiple characteristics of movement, such as mental processing and situation recognition

Question 8

What are the main types of reaction time?

Answer 8

1. Simple RT
2. Choice RT
3. Discrimination RT

Question 9

Simple RT (def)

Answer 9

one signal, one response

Question 10

Choice RT (def)

Answer 10

1+ signal with different response for each signal

Question 11

Discrimination RT (def)

Answer 11

1+ signal, one response

Question 12

Which type of reaction time is fastest?

Answer 12

Simple RT

Question 13

Which type of reaction time is most difficult?

Answer 13

Discrimination RT

Question 14

Where can the system break down in our patients’ reaction time?

Answer 14

• Perceiving sensation
• -> lack of peripheral sensation (diabetic neuropathy)
• -> perception of sensation (lesions in brain)
• Response selection
• -> brain injury, vertibular lesions
• Response execution
• -> slowed movement (Parkinson’s disease)
• -> musculoskeletal pain

Question 15

What are some task/environmental factors that influence the stimulus identification step of movement preparation?

Answer 15

• stimulus intensity
• stimulus type (auditory faster than visual)
• stimulus predictability (RT improves with predictability and with the addition of a warning “foreperiod”)

Question 16

What are some task/environmental factors that influence the response selection step of movement preparation?

Answer 16

• stimulus-response compatibility (high compatibility = decreased prep time)
• number of choices (Hick’s Law: more choices = longer RT)

Question 17

What are some task/environmental factors that influence the response execution step of movement preparation?

Answer 17

• movement complexity (biggest influence on movement time)

- accuracy demands (greater accuracy demands increased preparation time)

Question 18

What is the logarithmic speed/accuracy tradeoff?

Answer 18

Three interacting factors

1. how far you have to move
2. how fast you move
3. how accurate you need to be

Question 19

What is Fitts’ Law?

Answer 19

MT= a + b log2 (2D/W)
Basically, average movement time (MT) increases as movement amplitude (D) increases and target width (W) decreases. As targets get smaller or further apart, the MT gets longer. Applies to aiming tasks, reaching/grasping, piano playing, pegs into holes, etc.

Question 20

What is the influence of instruction type in the speed accuracy tradeoff?

Answer 20

• If emphasizing speed, movement latency will decrease at cost of accuracy.
• If emphasizing accuracy, movement speed will increase, but accuracy will improve.

Question 21

What are some performer characteristics that influence movement preparation?

Answer 21

• age
• sleep: are they well rested? deprivation causes longer RT
• physical fitness: more fit = faster RT
• task experience
• attention focus: signal (sensory set) and movement (motor set). signal is faster
• distraction: background noise = slower RT

Question 22

Signal (sensory set) attention focus (def)

Answer 22

focus on the sound of the signal (gun/buzzer)

Question 23

Movement (motor set) attention focus (def)

Answer 23

focus on moving as quickly as possible (movement required)

Question 24

Multi-tasking is an effective way to increase productivity. true/false

Answer 24

false; most motor vehicle accidents occur due to drive inattention with no significant difference between handheld and hands free devices. Texting is even worse.

Question 25

What are some clinical strategies for improving RT?

Answer 25

• increase size, contrast, and/or intensity of stimuli
• practice under a variety of stimulus conditions
• simplify the movement if possible
• pre-cue patients on what to expect
• teach patient to anticipate cue