Deck 11: Motor Control and Plasticity

Question 1

Electromyography studies have revealed that a voluntary movement of the arm is immediately preceded by

A) a brief cessation of breathing.
B) rapid eye movements.
C) recruitment of muscle fibers according to the "size principle."
D) a postural response.

Answer 1

D

Question 2

A complex set of commands to muscles that is established before a behavior starts is called a

A) closed-loop program.
B) temporary paralysis.
C) motor plan.
D) ballistic event.

Answer 2

C

Question 3

What is the relationship between feedback from movement and a motor program?

A) Feedback does little to change a motor program.
B) Feedback may inform a motor program about how the execution of a movement is unfolding.
C) Feedback affects only intrinsically organized motor programs.
D) Feedback provides only coarse modulation of a motor program.

Answer 3

B

Question 4

Refer to the figure.
The experiment in the figure demonstrated that

A) our behavior is the sum of reflexive responses to our environment.
B) impulses travel faster through the motor neurons that innervate our calf muscles.
C) a motor plan to stabilize our body precedes the pull of a lever.
D) the reflex for pulling a lever is slower than the reflex for stabilizing the body.

Question 5

In designing machines that will be operated by humans, engineers must balance conflicting objectives in relation to human movement controls. Specifically, there is always a trade-off between _______ and _______.

A) theory; practice
B) efficiency; safety
C) speed; accuracy
D) functionality; cost

Question 6

In open-loop control mechanisms, activity is

A) preprogrammed.
B) error-free.
C) very slow.
D) subject to feedback.

Question 7

Which statement about open-loop control systems is false?

A) They are not modulated by sensory feedback.
B) Activity is preprogrammed.
C) They are needed in systems that must respond very rapidly.
D) The control signal occurs after error is detected.

Question 8

The striped appearance of muscle fibers is due to the regular arrangement of thick _______ filaments and thin _______ filaments.

A) extrafusal; intrafusal
B) intrafusal; extrafusal
C) myosin; actin
D) afferent; efferent

Question 9

Muscles are connected to bone by

A) ligaments.
B) tendons.
C) myosin.
D) fascia.

Question 10

A high innervation ratio characterizes

A) control of coarse movements.
B) control of fine movements.
C) a state of near paralysis.
D) slow fibers.

Question 11

Deafferentation of the limb of humans or other primates results in

A) return of the Babinski reflex.
B) sustained withdrawal of all reflexes.
C) hyperkinetic movements.
D) disuse.

Question 12

Which of the following has been described as a "universal" joint?

A) Elbow
B) Knee
C) Hip
D) Any finger joint

Question 13

Which of the following is a property of fast-twitch muscle fibers?

A) Rapid fatigue
B) Ability to sustain long periods of muscle contraction
C) Used to maintain posture
D) Relatively high concentration of mitochondria

Question 14

The wrist joint has _______ plane(s) of movement.

A) one
B) two
C) three
D) multiple

Question 15

Muscles that act together are called

A) antagonists.
B) reciprocals.
C) muscle fibers.
D) synergists.

Question 16

Bending of the myosin head causes muscle filaments to

A) move farther apart.
B) produce new filaments.
C) shrink.
D) slide past one another.

Question 17

The motor unit is a

A) single motor axon and all the muscle fibers it innervates.
B) collection of axons that travel to the same muscle group.
C) collection of motor axons that produce the same movement.
D) single motor axon and a single muscle fiber.

Question 18

Fibers that lie within the muscle spindle are known as _______ fibers.

A) fast
B) extrafusal
C) Golgi
D) intrafusal

Question 19

Thick and thin filaments of muscle are made up of

A) actin and myosin.
B) fast and slow fibers.
C) synergists and antagonists.
D) intrafusal and extrafusal fibers.

Question 20

Bungarotoxin, found in the venom of some snakes, can be lethal because

A) it prevents the victim from moving his or her limbs.
B) it prevents the production of action potentials.
C) it potentiates ACh transmission.
D) it blocks ACh receptors, ultimately blocking contraction of the muscles necessary for breathing.

Question 21

What is(are) the transmitter(s) at the neuromuscular junction?

A) Endogenous opioids
B) Glutamate
C) Various peptides
D) Acetylcholine

Question 22

Duchenne's muscular dystrophy is associated with

A) excessive dystrophin production.
B) defective dystrophin production.
C) abnormal dystrophin receptors.
D) high androgen levels.

Question 23

Animal models for myasthenia gravis can be produced by

A) injecting animals with toxins that block neuromuscular junctions.
B) giving animals antibodies that attack acetylcholine receptors.
C) tiring the animal out on a perpetual treadmill.
D) suppressing the animal's immune system.

Question 24

Duchenne's muscular dystrophy is a type of inherited muscle disorder that involves

A) a single gene located on chromosome 9.
B) a single gene located on the X chromosome.
C) polygenic control mechanisms.
D) a single gene located on the Y chromosome.

Question 25

Golgi tendon organs report muscle

A) stretch.
B) damage.
C) contraction.
D) thickness.

Question 26

The gamma motor neurons innervate

A) small muscles.
B) large muscles.
C) muscle spindles.
D) spinal motoneurons.

Question 27

Stretch of a muscle first activates

A) spinal motoneurons.
B) muscle spindles.
C) gamma efferents.
D) slow motor fibers.

Question 28

The secondary sensory endings of muscle spindles are maximally responsive to

A) the rate of change of muscle length.
B) dynamic changes.
C) the weight of an object.
D) maintained muscle length.

Question 29

Muscle spindles function by means of the stretching of

A) Golgi tendon organs.
B) actin.
C) myosin.
D) extrafusal fibers.

Question 30

Muscle spindle tension is regulated by

A) secondary endings.
B) gamma efferents.
C) alpha motoneurons.
D) muscle size.

Question 31

The _______ of spinal reflexes can be modulated by descending projections from the brain.

A) inhibition or facilitation
B) inhibition, but not the facilitation
C) facilitation, but not the inhibition
D) None of the above; spinal reflexes are not modulated by the brain.

Question 32

Refer to the figure.
Which statement best describes the process illustrated in the figure?

A) When weight stretches a muscle, excited afferents directly excite the motor neuron of the muscle, and the muscle contracts.
B) Information terminating on the spinal interneuron in a stretch reflex facilitates contraction of antagonistic muscles to protect them from injury.
C) Interneurons in the stretch reflex inhibit over-contraction of the stretched muscle.
D) Spinal reflexes are not modulated by the brain.

Question 33

Endogenous rhythmic movements

A) are modulated solely in the primary and supplementary motor cortex.
B) are generated by central pattern generators.
C) in humans are modulated by the central pattern generator and the cerebral cortex but in other vertebrates, they are modulated only by the central pattern generator.
D) are generated by circuits within the spinal cord but cannot function independently of brain afferents.

Question 34

In rats with spinal cord cuts, transplanting _______ into the cut leads to the regeneration of corticospinal axons and some restoration of motor function.

A) olfactory neurons
B) ensheathing cells of the olfactory bulb
C) fetal motor neurons
D) undifferentiated epithelial cells

Question 35

Polioviruses destroy

A) cerebellar cells.
B) motoneurons.
C) basal ganglia cells.
D) cerebral motor cortical cells.

Question 36

A particular gene that has been found to be involved in some cases of amyotrophic lateral sclerosis may involve control of

A) acetylcholine.
B) muscle receptors.
C) copper/zinc superoxide dismutase.
D) dopamine.

Question 37

Which structure exists outside the CNS?

A) Trigeminal nucleus
B) Oculomotor nucleus
C) Ventral horn motor neurons
D) Motor neurons

Question 38

Nonprimary motor areas are especially active

A) following the execution of reflexes.
B) while rehearsing a movement without executing it.
C) following the completion of learned movements.
D) when learning to move a robotic arm.

Question 39

Primary cortex is called "executive" because it appears to control _______ movements.

A) complex
B) spontaneous
C) voluntary
D) rapid

Question 40

In experiments conducted with the purpose of developing algorithms for controlling robotic arms, researchers "decoded" activity from the _______ cortex.

A) primary motor
B) premotor
C) posterior parietal
D) orbitofrontal

Question 41

Refer to the figure showing an experiment in which one neuron is being measured under two conditions.
Which statement best explains why this neuron is not especially active in condition 2?

A) The M1 motor neuron being measured is specifically involved in picking up a box, but the subject realizes there is no box in condition B, so the motor neuron fires less robustly.
B) The mirror neuron being measured is specific to reaching for a box, and there is no box in condition B.
C) The mirror neuron being measured is from an autistic subject, thus this copycat neuron is underactive
D) The SMA neuron being measured is active in condition A, when the subject is reaching for a box, but not in condition B, when the subject is simply mentally rehearsing the complex movement sequence.

Question 42

Mental rehearsal of a complex motor task in humans is associated with

A) greater metabolic activity in the primary motor cortex.
B) enhanced metabolic activity in the primary motor cortex, somatosensory cortex, and supplementary motor area.
C) increased blood flow only in the supplementary motor area.
D) increased blood flow only in the visual cortex.

Question 43

The _______ has been implicated in externally guided motor sequences.

A) supplementary motor area
B) premotor cortex
C) primary motor cortex
D) cerebellum

Question 44

A monkey with a lesion in area F5 might have trouble

A) scratching.
B) eating.
C) understanding the movement of another monkey.
D) responding to pain.

Question 45

Cerebellar activity is correlated with activity of _______, whereas basal ganglia activity is associated with activity of _______.

A) M1; premotor cortex
B) premotor cortex; the SMA
C) the SMA; M1
D) premotor cortex; somatosensory cortex

Question 46

In general, species that have large cerebellums tend to display _______ motor behavior.

A) complex
B) rapid
C) accurate
D) open-loop

Question 47

The term "striatum" refers to

A) all the structures of the basal ganglia.
B) the cerebellum and the caudate nucleus.
C) the thalamus.
D) the caudate nucleus and putamen.

Question 48

Each basal ganglia consists of

A) the caudate nucleus, putamen, globus pallidus, substantia nigra, and subthalamic nucleus.
B) exclusive connections to the thalamus.
C) elaborate pathways to the cerebellum.
D) a striatum and a globus pallidus.

Question 49

Which statement about sensory connections to the cerebellum is correct?

A) Sensory inputs to the cerebellum are restricted to muscle receptors.
B) Minimal sensory connections are made to selected areas of the cerebellum.
C) Sensory inputs to the cerebellum are derived from virtually all sensory systems.
D) Visual and auditory inputs to the cerebellum are virtually nonexistent.

Question 50

Researchers have found that the AMPA receptors on Bergmann glia are important for regulating fine motor coordination in mice. Which observation would support this idea?

A) Selectively blocking glutamate transmission between granule cells and Purkinje cells affects motor behavior.
B) Selectively knocking out AMPA receptors on Bergmann glia does not affect general motor behavior but disrupts challenging motor behavior.
C) Glutamate agonists cause mice to run faster.
D) All of the above

Question 51

In order to use the Cre-lox system to study the role of AMPA receptors in Bergmann glia, researchers had to first

A) knock out lox sites.
B) antagonize glutamate transmission.
C) make mice that express the Cre gene only in glial cells.
D) insert lox sites into genes that encode for all glutamate receptors.

Question 52

Refer to the figure.
The individual depicted in the figure

A) had their prefrontal cortex removed due to seizures, and they now have trouble deciding how to move.
B) had their cerebellum removed due to seizures, and they now have trouble executing smooth movements.
C) was born without a cerebellum, but because of neuroplasticity, they have no motor deficiencies.
D) was born without a prefrontal cortex, but because of neuroplasticity, they have no difficulty deciding to move.

Question 53

The _______ is responsible for our ability to track visual objects as the head moves.

A) hippocampus
B) vestibulocerebellum
C) globus pallidus
D) putamen

Question 54

Alcoholic patients may have damage to the _______, which results in ataxic gait.

A) corpus striatum
B) pyramidal system
C) ventral horns
D) cerebellum

Question 55

A primary symptom of cerebellar pathology is

A) ataxic gait.
B) paralysis.
C) sudden jerking movements of the limbs.
D) choreic movements.

Question 56

Damage to _______ results in decomposition of movement.

A) striatal cells
B) the cerebral motor cortex
C) the spinal cord
D) the cerebellum

Question 57

Partial paralysis of one side of the body is a common result of damage to the

A) cerebral cortex.
B) spinal cord.
C) substantia nigra.
D) extrapyramidal system.

Question 58

The partial paralysis caused by damage to primary motor cortex is called

A) spasticity.
B) paresis.
C) apraxia.
D) flaccidity.

Question 59

Fetal cell transplants have been investigated as a treatment for Parkinson's disease, but some recipients develop severe involuntary movements. A possible reason for this outcome is

A) a deficit of dopamine in the brains of these patients.
B) excess acetylcholine in these patients.
C) that the fetal cells were placed in the wrong nucleus.
D) inappropriate signaling from the new dopamine cells.

Question 60

Which of the following is the fundamental pathological change in Parkinson's disease?

A) Death of neurons of the substantia nigra
B) Destruction of the caudate and putamen
C) Decreased availability of serotonin
D) Atrophy of motor cortex

Question 61

Which of the following is not a symptom of Parkinson's disease?

A) Sudden flinging movements of the arms
B) Loss of facial expression
C) Tremors at rest
D) Loss of spontaneous actions

Question 62

l-dopa can reverse some of the symptoms of

A) Duchenne's muscular dystrophy.
B) amyotrophic lateral sclerosis.
C) Parkinson's disease.
D) Huntington's chorea.

Question 63

Alzheimer's, Creutzfeldt-Jakob disease, and Parkinson's are similar in that all three

A) cause schizophrenia-like symptoms.
B) are associated with a buildup of misfolded proteins.
C) result in brain degeneration that produces a spongy brain.
D) are caused by $\alpha$ -synuclein fibrils.

Question 64

The genetic defect responsible for Huntington's disease was identified through the use of a _______ map.

A) somatotopic
B) neuroanatomical
C) pedigree
D) geographic distribution

Question 65

There is(are) _______ gene(s) related to Huntington's disease.

A) a single
B) two
C) an indeterminate number of
D) zero

Question 66

Huntington's disease is transmitted by

A) multiple genes inherited in a simple recessive manner.
B) genes located on several chromosomes.
C) a single dominant gene.
D) viruses.

Question 67

The technique known as _______ provides a measure of the electrical activity of muscle.

Question 68

Open-loop control is characteristic of _______ movements.

Question 69

Muscles that act together are called _______.

Question 70

The number of muscle fibers innervated by each motoneuron axon is called its _______.

Question 71

The specialized synapse between a motor neuron and a muscle fiber is called a(n) _______.

Question 72

Duchenne's muscular dystrophy affects boys almost exclusively because the implicated gene is located on the _______.

Question 73

The muscle fibers found within muscle spindles are called _______ fibers.

Question 74

Destruction of a stretch of the spinal cord (as opposed to a clean cut) results in _______ paralysis below the level of the injury.

Question 75

Motor neurons of the brain and spinal cord degenerate in _______.

Question 76

Work with transgenic mice has suggested that the _______ gene plays a role in ALS.

Question 77

Algorithms that predict the intended direction of arm movement from neural activity of the _______ cortex can allow an individual to control a robotic arm.

Question 78

Bergmann glia exert their effects in the cerebellum via _______ receptors.

Question 79

The vermis and the anterior lobe of the cerebellum are the upper portion of the _______.

Question 80

Study of a heritable form of Parkinson's disease in a large Italian family identified a defect in the gene that encodes the protein _______, which is normally expressed in the basal ganglia.