Section 3

Question 1

Conscious action relies on

Answer 1

cognitive processes and constant sensory feedback

Question 2

What are the different components required for generating complex movements?

Answer 2

Volition
Coordination of many muscle groups
Postural adjustments
Proprioception
Sensory signal processing
Adaptability

Question 3

Categories of movement

Answer 3

Voluntary (under volition control)
Reflexes (involuntary)
Rhymic motor patterns

Question 4

Three basic concepts of motor control

Answer 4

1. Fine motor control requires proprioception and efference copy - used for adjusting ongoing movements
2. Multiple levels of control and parallel circuits
3. Motor learning and motor programs - the process that motor programs are create and modified through practice

Question 5

Which of the following is incorrect?
A. fine control of movement relies on sensory feedback and a copy of the motor command
B. more cortical areas are active when performing learned vs new skills
C. Motor commands descend from the brain to the spinal cord to control motor activity
D. learning shifts the level of brain control.

Answer 5

B

Question 6

Which of the following is an important phenomenon about motor programs?
A. they are involuntary
B. they do not rely on sensory feedback
C. they are a variable sequence of movements
D. they can be completed with any muscle groups

Answer 6

D

Question 7

Types of muscles

Answer 7

Skeletal (flexors vs. extenders)
Smooth
Cardiac

Question 8

What happens at the neuromuscular junction of a motor unit?

Answer 8

Motor neuron fires, acetylcholine is released into the synapse and the muscle fibers within the motor unit contract

Question 9

Movement precision is based on the ____ ratio

Answer 9

innervation ratio - fine control is associated with less muscle fibers

Question 10

The regulation of muscle contraction requires

Answer 10

proprioceptors - without proprioception you can do very little with your movements

Question 11

What happens if someone loses proprioception?

Answer 11

the case of G.O. - no control of distance, direction, or velocity of movements

Question 12

Two main types of proprioception

Answer 12

Golgi tendon organs - respond to changes in muscle tension
muscle spindles - respond to changes in muscle length

Question 13

Firing of the Golgi tendon organs leads to

Answer 13

muscle relaxation

Question 14

Firing of the muscle spindles leads to

Answer 14

muscle contraction

Question 15

The role of the intrafusal muscle of the muscle spindles is to

Answer 15

maintain muscle spindle sensitivity so that it remains responsive to even slight changes in the length of extrafusal muscle

Question 16

Stretch reflex occurs when

Answer 16

the length of a muscle is suddenly extended (Detected by stretch receptors aka muscle spindles) leading to contraction
[ example - keeps you from falling when you are pushed ]

Question 17

The stretch reflex is the [simlest/most complex] spinal circuit

Answer 17

simplest

Question 18

The withdrawal reflex occurs when

Answer 18

you touch something painful

Question 19

How is the withdrawal reflex different from the stretch reflex?

Answer 19

the stretch reflex is monosynaptic; the withdrawal reflex is not - it involves interneurons

Question 20

Two main spinal circuit principles

Answer 20

Recipricol innervation - for coordinating antagonistic muscles
Recurrent collateral inhibition - distribute work between different units of a muscle’s motor pool

Question 21

Why do we need recurrent collateral inhibition?

Answer 21

if the muscle keeps firing and contracting there would be a build-up of acid and risk for injury, so there needs to be an inhibitor forcing the muscle to relax after enough work is done

Question 22

Walking and the spinal cord

Answer 22

walking is a complex sensorimotor program in which the CNS generates coordinated patterns of motor outputs

Question 23

At the bare minimum, walking is a series of

Answer 23

controlled stretch reflexes

Question 24

What is the organization of the primary motor cortex (M1)?

Answer 24

somatotopically organized (disproportionate representation)

Question 25

The M1 receives input from

Answer 25

secondary motor areas prefrontal cortex primary somatosensory cortex

Question 26

The effects of damage to the M1 include

Answer 26

mostly contralateral deficits astereognosis response weakness difficulty in moving body parts independently (not long-term paralysis)

Question 27

The primary motor cortex receives direct inputs from all the following areas except A. Primary somatosensory cortex B. SMA and Premotor cortex C. Secondary motor areas D. Basal ganglia

Answer 27

D

Question 28

In what ways is the primary motor cortex M1 similar to the primary somatosensory cortex S1? A. both are somatotopically organized B. both located in the frontal lobe C. both receive direct inputs from neurons in the spinal cord D. all of the above

Answer 28

A

Question 29

The two secondary motor areas are

Answer 29

the premotor cortex - movement preparation the supplementary motor areas - preparation for a rapid sequence of movements

Question 30

In what ways are the two M2 areas similar

Answer 30

anatomically similar - connected to the M1 and each other and have direct output to the brain stem functionally similar - electrical stimulation elicits complex movements in body parts and neurons fire prior to and during voluntary movements

Question 31

Effects of damage to the secondary motor areas (SMA) include

Answer 31

complex movement disorders difficulty in developing (planning/coordinating) movement strategies lack of coordination between hands

Question 32

Sensorimotor Association Areas regulate

Answer 32

higher levels of cognition - controlling, adapting, and being flexible with behavior

Question 33

Sensorimotor Association Areas include

Answer 33

PFC Posterior Parietal Cortex

Question 34

Prefrontal Cortex

Answer 34

highest in sensorimotor hierarchy mediates planning and decision making mental representation of motor plan (i.e. working memory)

Question 35

Damage to the PFC leads to

Answer 35

inability to organize thoughts in order to successfully plan

Question 36

Posterior Parietal Cortex

Answer 36

mediates multimodal integration action intention body and object position references

Question 37

Damage to the posterior parietal cortex results in

Answer 37

apraxia - inability to do what is asked contralateral neglect (usually damage to right parietal and affects abilities on left side)

Question 38

The two Descending motor pathways are

Answer 38

Dorsolateral corticospinal tracts - fingers, wrist, toes Ventromedial corticospinal tracts - shoulders, trunks, hips, legs

Question 39

The purpose of the descending motor pathways

Answer 39

the M1 sends signals to motor neurons in the spinal cord through these corticospinal tracts

Question 40

Motor cortex on one side of the cerebral hemisphere primarily controls the contralateral side of the body via the ________

Answer 40

dorsolateral corticospinal tracts

Question 41

Some muscle groups get projections from both hemispheres via these _________

Answer 41

ventromedial corticospinal tracts

Question 42

Two subcortical Motor Areas

Answer 42

The Cerebellum and the Basal Ganglia Inputs - cortical motor areas, brainstem, sensory Output - interact with different levels of cortical motor circuit (through thalamus to cortex OR directly to brainstem and spinal cord)

Question 43

All except the ____ and _____ have some direct connection to the spinal cord

Answer 43

prefrontal; parietal