Deck 8: The Sensorimotor System

Question 1

Small areas of secondary motor cortex were discovered in the

A) dorsolateral frontal lobe.
B) lateral prefrontal lobe.
C) cingulate gyrus.
D) posterior parietal lobe.
E) cerebellum.

Answer 1

cingulate gyrus.

Question 2

With respect to sensorimotor learning, the advantage of transferring control to lower circuits of the neural hierarchy is that it

A) frees the higher levels of the nervous system to deal with more complex issues.
B) increases the reliability of movements.
C) increases validity.
D) increases conscious awareness of the response.
E) both A and D

Answer 2

frees the higher levels of the nervous system to deal with more complex issues.

Question 3

In general the various areas of secondary motor cortex are thought to

A) terminate response sequences.
B) specialize in guiding learned sequences.
C) program specific motor sequences.
D) mediate reflexes.
E) provide the major input to spinal motor circuits.

Answer 3

program specific motor sequences.

Question 4

Which kinds of movements are not influenced by sensory feedback?

A) innate movements
B) unpracticed movements
C) practiced movements
D) ballistic movements
E) reflexive movements

Question 5

Much of the output of the posterior parietal cortex goes to the

A) dorsolateral prefrontal association cortex.
B) frontal eye field.
C) various areas of secondary motor cortex.
D) all of the above
E) both B and C

Question 6

The dorsolateral prefrontal association cortex

A) is important in the initiation of complex voluntary movements.
B) sends projections to the primary and secondary motor cortices.
C) plays a critical role in the elicitation of reflexes.
D) both A and B
E) both B and C

Question 7

Which structure is thought to be involved in the integration of the sensory information that is the basis for initiating a movement?

A) posterior parietal cortex
B) primary somatosensory cortex
C) primary auditory cortex
D) frontal cortex
E) primary visual cortex

Question 8

A neurological patient who shaves only the right side of his face and does not put his left arm into his sweater likely has a lesion in the right

A) premotor area.
B) supplementary motor cortex.
C) posterior parietal lobe.
D) dorsolateral frontal lobe.
E) primary motor area.

Question 9

During sensorimotor learning,

A) the locus of control is often shifted to lower levels of the sensorimotor hierarchy.
B) the locus of control is often shifted from conscious to unconscious control mechanisms.
C) individual responses are often integrated into continuous motor programs.
D) all of the above
E) both A and B

Question 10

Contralateral neglect is usually associated with large lesions of the

A) right parietal lobe.
B) left parietal lobe.
C) right frontal lobe.
D) left frontal lobe.
E) right temporal lobe.

Question 11

Like the sensory systems, the sensorimotor system is

A) hierarchical.
B) parallel.
C) functionally segregated.
D) all of the above
E) none of the above

Question 12

Large lesions to the right parietal lobe sometimes produce

A) ipsilateral astereognosia.
B) contralateral neglect.
C) apraxia.
D) all of the above
E) none of the above

Question 13

Some of the supplementary motor area is in the

A) longitudinal fissure.
B) lateral fissure.
C) parietal cortex.
D) temporal cortex.
E) inferotemporal cortex.

Question 14

Apraxia is usually caused by lesions to the

A) left parietal lobe.
B) right parietal lobe.
C) right primary motor cortex.
D) right secondary motor cortex.
E) either temporal lobes.

Question 15

Which of the following is a principle of sensorimotor organization?

A) The sensorimotor system is hierarchically organized.
B) Motor output is guided by sensory input.
C) Learning changes the nature and locus of sensorimotor control.
D) all of the above
E) both A and B

Question 16

The decision to initiate a voluntary response seems to be made in the

A) posterior occipital cortex.
B) dorsolateral prefrontal cortex.
C) primary motor cortex.
D) premotor cortex.
E) supplementary motor area.

Question 17

Without the sensory feedback carried by the somatosensory nerves of the arms, human neurological patients, such as G.O., have difficulty

A) swatting a fly.
B) maintaining a constant appropriate level of manual muscle contraction.
C) adjusting the output of the muscles of their arms to compensate for unexpected external disturbances (e.g., somebody brushing against an arm).
D) all of the above
E) both B and C

Question 18

The supplementary motor area and the premotor cortex are considered to be areas of

A) the parietal lobe.
B) association cortex.
C) secondary somatosensory cortex.
D) secondary motor cortex.
E) the primary motor cortex.

Question 19

Apraxia typically affects

A) only the left side of the body.
B) only the right side of the body.
C) both sides of the body.
D) only the hands.
E) only the legs.

Question 20

The supplementary motor area and the premotor cortex are in the

A) frontal lobe.
B) temporal lobe.
C) parietal lobe.
D) occipital lobe.
E) limbic lobe.

Question 21

Signals from the left primary motor cortex descend through the spinal cord white matter in one of

A) three major tracts.
B) four major tracts.
C) five major tracts.
D) six major tracts.
E) eight major tracts.

Question 22

A deficit in the ability to recognize objects by touch is called

A) apraxia.
B) asomatognosia.
C) stereognosis.
D) astereognosia.
E) homunculus.

Question 23

Which of the following receives information from various parts of the cortex and feeds it back to motor cortex?

A) basal ganglia
B) cerebellum
C) red nucleus
D) reticular formation
E) substantia nigra

Question 24

Long bursts of stimulation applied to the primary motor cortex elicit

A) simple movements of one joint.
B) simple contractions of one muscle.
C) complex natural-looking response sequences.
D) reflexes.
E) either A or B

Question 25

Neurons that fire in response to making a particular response, observing somebody else making the response, or just thinking about the response are called

A) supplementary motor neurons.
B) premotor neurons.
C) mirror neurons.
D) both A and B
E) both A and C

Question 26

In 1937, the primary motor cortex was mapped by electrically stimulating the cortex of conscious human subjects who were undergoing neurosurgery.This was accomplished by

A) Hebb.
B) Mana.
C) Jackson.
D) Penfield and Boldrey.
E) Sperry.

Question 27

The somatotopic map of the primary motor cortex is called the

A) motor homunculus.
B) somatosensory homunculus.
C) stereognosis.
D) somatotopic homunculus.
E) supplementary map.

Question 28

Current theories of the function of the basal ganglia emphasize their

A) role in modulating motor output.
B) involvement in a variety of cognitive processes.
C) systematic anatomical organization.
D) all of the above
E) both A and B

Question 29

The consequences of cerebellar damage include

A) difficulty in maintaining steady postures.
B) inability to precisely control the direction, force, velocity, and amplitude of movements.
C) inability to adapt patterns of motor output to changing conditions.
D) severe disturbances of balance, gait, speech, and eye movement.
E) all of the above

Question 30

It has been estimated that over half the neurons of the brain are in a structure that constitutes only 10% of the brain's total mass.This structure is the

A) neocortex.
B) cerebellum.
C) hippocampus.
D) brain stem.
E) corpus callosum.

Question 31

Recent fMRI studies have changed the traditional view of the cerebellum by suggesting that in addition to its sensorimotor functions it is involved in

A) motor learning.
B) control and learning of cognitive responses.
C) learning motor sequences.
D) correcting motor sequences.
E) integrating motor sequences.

Question 32

In the primary motor cortex, the neurons that participate in the movement of a particular finger are

A) located in one somatotopically segregated finger area.
B) widely distributed over the somatotopic hand area.
C) all located in a single column.
D) all located in the left parietal lobe.
E) all located in the right parietal lobe.

Question 33

A study of the firing of primary motor cortex neurons while monkeys moved freely about indicated that their firing was often related to the

A) direction of the movement.
B) speed of the movement.
C) end point (i.e., target) of the movement.
D) acceleration of the movement.
E) purpose of the movement.

Question 34

In a remarkable demonstration, Belle, the owl monkey, controlled the movements of a robotic arm

A) by pressing buttons.
B) with the activity of neurons in her primary motor cortex.
C) with speech sounds.
D) with monkey calls.
E) by providing visual feedback to the arm.

Question 35

The cerebellum is thought to

A) correct ongoing movements that deviate from their intended course.
B) play a major role in motor learning, particularly when timing is critical.
C) conduct signals from the cortex to the spinal cord.
D) all of the above
E) both A and B

Question 36

Which part of the body has been found to be doubly represented in each primary motor area of monkeys?

A) tongue
B) contralateral lip
C) contralateral hand
D) genitals
E) contralateral foot

Question 37

The primary motor cortex receives cutaneous feedback from only one part of the body: the hands.This feedback likely plays an important role in

A) stereognosis.
B) astereognosia.
C) the homunculus.
D) the cingulate motor areas.
E) apraxia.

Question 38

Which structure is part of a loop including the cortex and the basal ganglia?

A) thalamus
B) vestibular nucleus
C) cerebellum
D) red nucleus
E) substantia nigra

Question 39

The only parts of each motor homunculus to receive somatosensory feedback directly from skin are the

A) genital areas.
B) lip areas.
C) hand areas.
D) foot areas.
E) face areas.

Question 40

The effects of damage to the primary motor cortex include

A) astereognosia.
B) difficulty in moving one part of the body independently of others.
C) paralysis.
D) all of the above
E) both A and B

Question 41

Which midbrain structure receives visual and auditory information about spatial location?

A) tectum
B) cerebellum
C) basal ganglia
D) tegmentum
E) vestibular nucleus

Question 42

In the classic experiments of Lawrence and Kuypers, the descending motor tracts of monkeys were transected.The results of these experiments suggest that the function of the ventromedial pathways is the control of

A) posture.
B) movements of the body core and associated arm movements.
C) reaching for objects.
D) all of the above
E) both A and B

Question 43

When a motor neuron fires, all of the muscle fibers of its motor

A) unit contract together.
B) pool contract together.
C) segment contract together.
D) equivalence contract together.
E) feedback contract together.

Question 44

Only primates and a few other species, such as hamsters and raccoons, have cortical neurons that synapse directly on

A) muscles.
B) muscles of the fingers and thumb.
C) motor neurons that project to the muscles of the fingers and thumb.
D) spinal interneurons.
E) targets in the PNS.

Question 45

The axons of Betz cells are part of the

A) dorsolateral corticospinal tract.
B) dorsolateral corticorubrospinal tract.
C) anterolateral pathway.
D) ventromedial cortico-brainstem-spinal tract.
E) ventromedial corticospinal tract.

Question 46

In neuroanatomy, "rubro" refers to the

A) substantia nigra.
B) vestibular system.
C) caudate.
D) red nucleus.
E) cerebellum.

Question 47

In general, the ventromedial descending motor tracts control the muscles of the

A) thumbs.
B) fingers.
C) trunk.
D) toes.
E) face.

Question 48

In contrast to the ventromedial corticospinal tract, before descending to the spinal cord, the ventromedial cortico-brainstem-spinal tract interacts with the

A) tectum.
B) reticular formation.
C) vestibular nuclei.
D) all of the above
E) none of the above

Question 49

In which of the following structures would the motor units likely be the smallest?

A) finger
B) leg
C) arm
D) foot
E) back

Question 50

In the transection experiments of Lawrence and Kuypers, monkeys with all their dorsolateral motor pathways transected sat with their arms hanging limply by their sides.However, these same monkeys had no difficulty

A) picking up pieces of food and then releasing them.
B) using their arms for standing, walking, and climbing.
C) reaching for moving objects.
D) moving their fingers independently.
E) all of the above

Question 51

Most axons of the dorsolateral corticorubrospinal tract synapse on

A) muscles of the fingers and thumb.
B) muscles of the hands and wrists.
C) interneurons of the spinal gray matter that in turn synapse on motor neurons that project to the distal muscles of the arms and legs.
D) motor neurons that project to the hands.
E) Betz cells.

Question 52

Which of the following brain stem structures receives direct sensory information about balance?

A) cerebellum
B) reticular formation
C) vestibular nucleus
D) tectum
E) red nucleus

Question 53

The descending pathway illustrated here is the

A) dorsolateral corticorubrospinal tract.
B) dorsolateral corticospinal tract.
C) ventromedial corticospinal tract.
D) ventromedial cortico-brainstem-spinal tract.
E) none of the above

Question 54

In general, the dorsolateral corticospinal tract controls the muscles of the

A) thighs.
B) body core.
C) hands and feet.
D) proximal limbs.
E) legs.

Question 55

The decussation in the medullary pyramids is part of the

A) dorsolateral corticospinal tract.
B) dorsolateral corticorubrospinal tract.
C) ventromedial corticospinal tract.
D) ventromedial cortico-brainstem-spinal tract.
E) both C and D

Question 56

In contrast to the descending dorsolateral motor pathways, the ventromedial pathways

A) control the trunk.
B) are more diffuse.
C) are more strictly contralateral.
D) all of the above
E) both A and B

Question 57

The cell bodies of Betz cells are found in the

A) premotor cortex.
B) primary motor cortex.
C) supplementary motor cortex.
D) cerebellum.
E) basal ganglia.

Question 58

Monkeys had difficulty letting go of food after their

A) dorsolateral corticorubrospinal tracts were transected.
B) dorsolateral corticospinal tracts were transected.
C) ventromedial corticospinal tracts were transected.
D) cerebellum was lesioned.
E) basal ganglia were lesioned.

Question 59

In contrast to the axons of the descending dorsolateral motor pathways, individual axons of the ventromedial pathways often terminate

A) directly on motor neurons.
B) in two or more segments.
C) on both sides of the spinal cord.
D) both A and B
E) both B and C

Question 60

Monkeys could not move their fingers independently after transections of the

A) dorsolateral corticospinal tracts.
B) dorsolateral corticorubrospinal tracts.
C) ventromedial corticospinal tracts.
D) ventromedial cortico-brainstem-spinal tracts.
E) nigrostriatal tract.

Question 61

The latency of withdrawal reflexes indicates that the fastest withdrawal reflex neural circuit involves

A) no synapses.
B) 1 synapse.
C) 2 synapses.
D) 3 synapses.
E) more than 3 synapses.

Question 62

The patellar tendon reflex is a

A) conditioned reflex.
B) stretch reflex.
C) withdrawal reflex.
D) monosynaptic reflex.
E) both B and D

Question 63

All of the motor neurons that innervate the fibers of a single muscle are called its

A) motor unit.
B) discharge unit.
C) motor pool.
D) antagonists.
E) agonists.

Question 64

The patellar tendon reflex is a

A) withdrawal reflex.
B) reciprocal reflex.
C) stretch reflex.
D) recurrent reflex.
E) multisynaptic reflex.

Question 65

Which of the following requires an inhibitory interneuron?

A) reciprocal innervation
B) recurrent collateral inhibition
C) isometric contraction
D) all of the above
E) both A and B

Question 66

Intrafusal is to extrafusal as

A) voluntary is to ballistic.
B) muscle spindle is to skeletal muscle.
C) voluntary is to reflex.
D) dynamic is to static.
E) CNS is to PNS.

Question 67

About how many motor neurons are there in the typical motor unit?

A) 4
B) 1
C) 100
D) 1,000
E) 150

Question 68

Muscles are protected from damage caused by excessive contraction by

A) gamma efferents.
B) spindle afferents.
C) extrafusal motor pools.
D) Golgi tendon organs.
E) synergistic muscles.

Question 69

Increases in muscle tension in the absence of any shortening of the muscle are said to be

A) contractions.
B) dynamic.
C) extensions.
D) isometric.
E) synergistic.

Question 70

So-called fast muscle fibers

A) are pale.
B) are bright red.
C) can generate great force for long periods.
D) are found exclusively in extensors.
E) are found exclusively in flexors.

Question 71

Illustrated here is a

A) patellar tendon reflex.
B) withdrawal reflex.
C) stretch reflex.
D) both A and B
E) both A and C

Question 72

The tension of a muscle can be increased by increasing

A) the number of active neurons in its motor pool.
B) the level of activity of neurons in its motor pool.
C) the number of active neurons in its motor unit.
D) all of the above
E) both A and B

Question 73

The biceps and triceps are

A) synergistic.
B) dynamic.
C) isometric.
D) extensors.
E) antagonistic.

Question 74

The motor units of the thumb, fingers, and face contain the

A) fewest muscle fibers.
B) most muscle fibers.
C) fewest motor neurons.
D) most motor neurons.
E) most extensors.

Question 75

The muscle illustrated here is

A) an intrafusal muscle.
B) an extrafusal muscle.
C) a skeletal muscle.
D) both A and C
E) Both B and C

Question 76

Bob tried to open a jar of pickles, but the lid did not budge.The muscles of his hands and arms were

A) in isometric contraction.
B) in dynamic contraction.
C) locked in a stretch reflex.
D) in motor pools.
E) in extension.

Question 77

Which of the following helps distribute the work between different motor neurons of a muscle's motor pool?

A) cocontraction
B) recurrent collateral inhibition
C) reciprocal inhibition
D) muscle-spindle feedback
E) withdrawal reflex

Question 78

During a stretch reflex, the extrafusal motor neuron is excited directly by the

A) intrafusal motor neuron.
B) muscle spindle receptor.
C) spindle afferent neuron.
D) intrafusal muscle.
E) muscle.

Question 79

Muscle spindles provide the CNS with information about muscle

A) fatigue.
B) length.
C) tension.
D) color.
E) location.

Question 80

The motor neuron illustrated here is

A) a spindle afferent neuron.
B) an intrafusal neuron.
C) an extrafusal neuron.
D) an agonist neuron.
E) an antagonist neuron.