Ch. 19

Question 1

1. Compared to the neural circuits responsible for reflexes of invertebrates, the circuits of vertebrates involve
   a. many more steps in sequence.
   b. fewer steps in sequence.
   c. many more individual neurons to complete the same steps.
   d. fewer individual neurons to complete the same steps.
   e. neurons that can be more easily identified individually.

Answer 1

C

Question 2

2. According to the principle of reciprocity, when a muscle is stimulated to contract, its
   a. agonists and antagonists also contract.
   b. agonists and antagonists relax.
   c. agonists contract while its antagonists relax.
   d. antagonists contract while its agonists relax.
   e. contralateral muscles also contract.

Answer 2

C

Question 3

3. Agonists are
   a. sensory fibers that detect pain in order to trigger protective reflexes.
   b. muscles that extend a joint.
   c. pain-inducing stimuli.
   d. muscles that work together to generate a given motion.
   e. muscles that have opposing actions.

Answer 3

D

Question 4

4. The muscle fibers in a muscle spindle
   a. are not true muscle fibers because they cannot contract.
   b. are innervated by α motor neurons.
   c. function to maintain tension on spindle stretch receptors.
   d. are recruited only during very high force contractions.
   e. are recruited only during very low force contraction.

Answer 4

C

Question 5

5. When your family physician taps your left patellar tendon with a mallet,
   a. the intrafusal muscle fibers in your left patellar tendon contract.
   b. the intrafusal muscle fibers in your left quadriceps contract.
   c. many motor neurons innervating your left quadriceps are excited by 1a afferent fibers.
   d. a single motor neuron innervating your left quadriceps is excited by a 1a afferent fiber.
   e. a single motor neuron innervating your left quadriceps is inhibited by a 1a afferent fiber.

Answer 5

C

Question 6

6. When your family physician taps your left patellar tendon with a mallet, motor neurons innervating the _______ are excited and motor neurons innervating the _______ are inhibited.
   a. left knee extensors; left knee flexors
   b. left knee extensors; right knee extensors
   c. right knee extensors; left knee flexors
   d. right knee extensors; left knee extensors.
   e. left knee flexors; right knee flexors

Answer 6

A

Question 7

7. When your family physician taps your left patellar tendon with a mallet, motor neurons innervating the flexors of the left knee are inhibited by _______ in the _______.
   a. interneurons; muscle
   b. interneurons; tendon
   c. interneurons; brain
   d. interneurons; spinal cord
   e. sensory neurons; muscle

Answer 7

D

Question 8

8. In the stretch reflex, a signal from a sensory neuron that detects stretch in a muscle reaches a motor neuron innervating the stretched muscle via
   a. excitatory interneurons in the brain.
   b. inhibitory interneurons in the brain.
   c. a single excitatory synapse.
   d. inhibitory interneurons in the spinal cord.
   e. direct sensory-to-motor-neuron synapses as well as excitatory spinal interneurons.

Answer 8

E

Question 9

9. Which of the following illustrates the principle of divergence?
   a. A single muscle spindle afferent stimulates a single spinal motor neuron.
   b. A single pain receptor afferent stimulates a single spinal interneuron.
   c. Each motor neuron receives input from thousands of synapses.
   d. A single muscle spindle afferent stimulates many motor neurons.
   e. Each motor neuron receives input that has passed through multiple synapses on its way from the CNS.

Answer 9

D

Question 10

10. When you step on a tack, excitation of sensory afferents leads to excitation of motor neurons innervating one set of muscles and inhibition of motor neurons innervating another set of muscles. The stimulus produces opposite responses in different motor neurons because
    a. the afferent neuron releases different neurotransmitters at different synapses.
    b. motor neurons innervating different muscles have different receptors.
    c. motor neurons innervating different muscles release different neurotransmitters at the neuromuscular junction.
    d. the signals reach some motor neurons via excitatory interneurons but they reach other motor neurons via inhibitory interneurons.
    e. the sensory afferents transmit both excitatory and inhibitory action potentials that are sent to different motor neurons.

Answer 10

D

Question 11

11. When you are walking barefoot and your left foot lands on a marble,
    a. the extensors of your left leg contract.
    b. the flexors of your left leg relax.
    c. the extensors of your right leg contract.
    d. the flexors of your right leg contract.
    e. both the extensors and flexors of your left leg contract.

Answer 11

C

Question 12

12. When you voluntarily pick up an object such as a glass of milk,
    a. α motor neurons stimulate extrafusal muscle fibers to contract, while γ motor neurons stimulate the ends of intrafusal muscle fibers to contract.
    b. γ motor neurons stimulate extrafusal muscle fibers to contract, while α motor neurons stimulate the ends of intrafusal muscle fibers to contract.
    c. α motor neurons stimulate extrafusal muscle fibers to contract, while γ motor neurons stimulate the ends of intrafusal muscle fibers to relax.
    d. γ motor neurons stimulate extrafusal muscle fibers to contract, while α motor neurons stimulate the ends of intrafusal muscle fibers to relax.
    e. α motor neurons stimulate intrafusal muscle fibers to contract, while γ motor neurons stimulate the ends of extrafusal muscle fibers to relax.

Answer 12

A

Question 13

13. If only α motor neurons were activated during a voluntary movement, the muscle spindle would be unable to transmit information to correct the rate of the movement because the
    a. extrafusal fibers would not shorten.
    b. α motor neurons would inhibit the spindle.
    c. intrafusal fibers would be stretched excessively.
    d. intrafusal fibers would be slack.
    e. intrafusal fibers would remain at their resting length.

Answer 13

D

Question 14

14. If you voluntarily lift an object and have correctly judged its weight,
    a. the intrafusal muscle fibers shorten at a rate that maintains constant tension on the stretch receptor.
    b. the intrafusal muscle fibers do not contract.
    c. the muscle spindle afferents fire a rapid burst of action potentials.
    d. α motor neurons fire action potentials but γ motor neurons do not.
    e. γ motor neurons fire action potentials but α motor neurons do not.

Answer 14

A

Question 15

15. If you voluntarily lift an object and have underestimated its weight,
    a. the intrafusal muscle fibers shorten at a rate that maintains constant tension on the stretch receptor.
    b. the intrafusal muscle fibers do not contract.
    c. the muscle spindle afferents fire a rapid burst of action potentials.
    d. α motor neurons fire action potentials but γ motor neurons do not.
    e. γ motor neurons fire action potentials but α motor neurons do not.

Answer 15

C

Question 16

16. If you voluntarily lift an object and have underestimated its weight,
    a. a burst of action potentials from the muscle spindle afferents causes the contracting muscles to contract more forcefully.
    b. a burst of action potentials from the muscle spindle afferents causes the contracting muscles to stop contracting.
    c. the absence of action potentials from the muscle spindle afferents causes the contracting muscles to contract more forcefully.
    d. the absence of action potentials from the muscle spindle afferents causes the contracting muscles to stop contracting.
    e. there is no way to adjust the force of the contraction once the motion has begun.

Answer 16

A

Question 17

17. In rhythmic behavior such as human walking, each muscle contraction occurs in response to
    a. nerve action potentials originating in the CNS.
    b. nerve action potentials originating in peripheral neurons.
    c. nerve action potentials originating in proprioceptors.
    d. stretch reflexes originating in the muscle.
    e. spontaneous action potentials originating in muscle cells.

Answer 17

A

Question 18

18. According to the peripheral control model of insect flight,
    a. sensory detection of wing depression stimulates motor neurons innervating the depressor muscles.
    b. sensory detection of wing depression stimulates motor neurons innervating the levator muscles.
    c. motor neurons stimulating the depressors also stimulate the levators.
    d. motor neurons stimulating the depressors also inhibit the levators.
    e. sensory detection of wind causes the depressors to contract.

Answer 18

B

Question 19

19. Which of the following experimental results would demonstrate that central pattern generators are involved in generating the muscle contractions involved in rhythmic movement?
    a. A decerebrate cat (in which a portion of the brain has been removed) can walk and run on a treadmill.
    b. A decerebrate cat (in which a portion of the brain has been removed) has impaired balance on a treadmill.
    c. An insect in which sensory afferents from the wings have been cut can fly.
    d. An insect in which sensory afferents from the wings have been cut has an unusually slow wingbeat frequency.
    e. The stretch receptor monitoring wing elevation in an insect excites motor neurons to the depressors.

Answer 19

C

Question 20

20. How are central pattern generators and peripheral reflexes thought to interact in normal locomotion?
    a. Peripheral reflexes initiate locomotion but central pattern generators maintain it.
    b. Central pattern generators initiate locomotion and peripheral reflexes maintain it.
    c. Central pattern generators initiate and maintain locomotion and reflexes correct and fine-tune motion.
    d. Central pattern generators control locomotion with no input from peripheral reflexes.
    e. Peripheral reflexes control locomotion with no input from central pattern generators.

Answer 20

C

Question 21

21. A cellular oscillator in a central pattern generator is a cell
    a. whose membrane potential responds to stimulation from other cells.
    b. whose membrane potential goes through regular cycles of depolarization and repolarization.
    c. whose membrane potential is unusually resistant to depolarization or hyperpolarization.
    d. that has no synaptic connections to other cells.
    e. that fires action potentials.

Answer 21

B

Question 22

24. Oscillatory networks based on the half-center model are unstable unless
    a. there is a stabilizing mechanism that helps the first neuron that depolarizes to remain depolarized.
    b. there is a stabilizing mechanism so that the first neuron that fires action potentials keeps firing action potentials.
    c. there is a fatigue mechanism so that the first neuron that fires action potentials stops firing action potentials.
    d. there is a fatigue mechanism so that the external command stimulation stops.
    e. the same neuron always depolarizes first.

Answer 22

C

Question 23

25. The stomatogastric ganglion of decapod crustaceans has received extensive study because
    a. control of the crustacean stomach is very similar to control of the human stomach.
    b. the stomatogastric ganglion is the simplest oscillator studied to date.
    c. the stomatogastric ganglion is a pure cellular oscillator.
    d. the stomatogastric ganglion generates a variety of rhythmic output with a small number of neurons.
    e. the drugs that act on the stomatogastric ganglion are likely to have effects similar to those that act on the human digestive tract.

Answer 23

D

Question 24

26. Neuromodulators of the stomatogastric ganglion of a decapod crustacean would be least likely to do which of the following?
    a. Activate rhythmic muscle contractions of the stomach
    b. Speed up the rhythm of contractions in the stomach
    c. Slow down the rhythm of contractions in the stomach
    d. Change the order in which the neurons of the pyloric circuit contract
    e. Alter the strength of muscle contractions in the stomach

Answer 24

D

Question 25

28. The action potentials that directly trigger muscle contractions of walking movements in a vertebrate animal are initiated by neurons whose cell bodies are located in the
    a. motor cortex.
    b. cerebellar cortex.
    c. basal ganglia.
    d. spinal cord.
    e. peripheral ganglia.

Answer 25

D

Question 26

29. Experiments in which cats with transected spinal cords are able to walk on treadmills demonstrate that the
    a. brain initiates walking in cats.
    b. brain does not normally initiate walking in cats.
    c. brain controls the timing of repetitive limb movements in cats.
    d. brain does not control the timing of repetitive limb movements in cats.
    e. spinal cord is not necessary for communication between the brain and the limbs.

Answer 26

D

Question 27

30. Injections of the norepinephrine precursor L-dopa can enable spinally transected cats to walk on a treadmill. The most likely explanation for this result is that
    a. the injected L-dopa directly stimulates spinal motor neurons and causes muscle contractions.
    b. the injected L-dopa is converted to norepinephrine, which directly stimulates spinal motor neurons to cause muscle contractions.
    c. norepinephrine acts on the neuromuscular junctions of the limb muscles and causes muscle contractions.
    d. norepinephrine activates sensory afferents that cause reflex muscle contractions in the limbs.
    e. norepinephrine activates the central pattern generator that causes rhythmic stepping motions.

Answer 27

E

Question 28

31. Modeling experiments on walking and swimming in robotic salamanders suggest that
    a. each type of repetitive motion that an animal performs is controlled by a distinct central pattern generator.
    b. some repetitive motions are controlled by a central pattern generator, but others are not.
    c. a particular central pattern generator always produces the same pattern of limb movements.
    d. simple changes in the coordination of central pattern generators can produce different locomotor patterns.
    e. a given central pattern generator can be involved in only one type of movement.

Answer 28

D

Question 29

32. In the network of central pattern generators that governs walking and swimming in salamanders,
    a. movement is normally initiated by sensory input from the limbs.
    b. oscillators on opposite sides of the body are coupled so that they are active at the same time.
    c. stronger stimulation causes trunk oscillation to prevail over limb movements.
    d. stronger stimulation increases the rate of movement and force of both trunk and limb muscles.
    e. identical stimulation patterns can generate either walking or swimming movements depending on whether the animal is or is not in water.

Answer 29

C

Question 30

33. In the primary motor cortex, the neurons most responsible for sending motor output to spinal motor neurons are the
    a. mirror neurons.
    b. pyramidal cells.
    c. Purkinje cells.
    d. granule cells.
    e. basket cells.

Answer 30

B

Question 31

34. Output from the primary motor cortex consists mostly of action potentials that are transmitted to
    a. individual muscle fibers.
    b. synapses with motor neurons in the brain.
    c. synapses with motor neurons in the spinal cord.
    d. synapses with interneurons in the spinal cord.
    e. the cerebellum.

Answer 31

D

Question 32

35. The primary motor cortex contains neurons that
    a. make decisions about what movements to undertake.
    b. encode the force and/or direction of movements.
    c. send action potentials to muscle fibers.
    d. correspond to individual muscles according to location in the cortex.
    e. connect to no other areas of the brain.

Answer 32

B

Question 33

36. Evidence for the role of the primary motor cortex comes from experiments that show that
    a. activation of individual neurons of the motor cortex matches activation of individual muscles.
    b. activation of individual neurons of the motor cortex matches activation of individual motor units.
    c. activity of some neurons of the motor cortex correlates with the force or direction of a movement.
    d. a single action potential in a neuron of the motor cortex produces a single muscle twitch.
    e. the number of motor cortex neurons that fire action potentials is linearly related to the force of the muscle contraction.

Answer 33

C

Question 34

37. Electrical recordings from human volunteers indicate that the decision to move a body part and the signals generating that movement arise from
    a. one specific area of the motor cortex.
    b. one specific area of the cerebellum.
    c. one specific area of the spinal cord.
    d. one specific area of the frontal cortex.
    e. interactions of multiple cortical regions.

Answer 34

E

Question 35

38. A readiness potential is
    a. a localized electrical potential within the primary motor cortex that corresponds precisely to the intended movement.
    b. a broad wave of electrical activity in the cerebral cortex that precedes a voluntary movement.
    c. a graded depolarization of the muscle fibers in a motor unit that makes it easier for them to reach threshold in response to sensory input.
    d. a graded depolarization of spinal motor neurons that makes it easier for them to reach threshold in response to sensory input.
    e. an electrical potential generated in the cerebellum in preparation for a voluntary movement.

Answer 35

B

Question 36

39. The frontal cortex contains areas that are involved in
    a. receiving visual or auditory stimuli that might trigger a movement.
    b. receiving sensory feedback on limb positions.
    c. monitoring and correcting the accuracy of movement.
    d. planning and organizing movement.
    e. sending signals to muscle fibers.

Answer 36

D

Question 37

40. The main role of the cerebellum is to
    a. make decisions on what voluntary movements to perform.
    b. plan the sequence of muscle contractions involved in an involuntary movement.
    c. send the signals to activate muscle fibers involved in a voluntary movement.
    d. send the signals to activate muscle fibers involved in an involuntary movement.
    e. provide feedback to correct errors as a voluntary movement is performed.

Answer 37

E

Question 38

41. Output from the cerebellar cortex is sent by
    a. gasket cells.
    b. Golgi cells.
    c. granule cells.
    d. Purkinje cells.
    e. stellate cells.

Answer 38

D

Question 39

42. The involvement of the cerebellum in motor learning is demonstrated by the observation that patients with cerebellar lesions
    a. are paralyzed on one side of their body.
    b. are paralyzed on both sides of their body.
    c. are capable of voluntary movements but are clumsy and uncoordinated.
    d. are capable of coordinated movement if they are helped with initiating the movement.
    e. fatigue easily.

Answer 39

C

Question 40

43. The involvement of the cerebellum in preprogramming voluntary movements is demonstrated by the observation that many patients with cerebellar lesions
    a. fatigue easily.
    b. are paralyzed on one side of their body.
    c. are paralyzed on both sides of their body.
    d. are capable of coordinated movement if they are helped with initiating the movement.
    e. are capable of voluntary movements but must think about each step in complex movements individually.

Answer 40

E

Question 41

44. Most of the neurons in the basal ganglia are inhibitory. How can an inhibitory synapse be involved in generating a movement?
    a. Inhibitory action potentials are converted to excitatory action potentials when they arrive at the neuromuscular junction.
    b. Inhibition of a tonically active inhibitory neuron results in disinhibition of its target neuron.
    c. Muscle fibers receive the inhibitory input and convert it into excitatory input.
    d. Inhibiting other motor pathways automatically excites the relevant motor pathway.
    e. Motor neurons are unaffected by inhibitory neurotransmitters.

Answer 41

B

Question 42

45. Excitatory inputs from the cerebral cortex to the striatum will lead to what effects on corresponding neurons downstream in the direct pathway of the basal ganglia?
    a. Excitation in the globus pallidus and inhibition in the thalamus
    b. Excitation in the globus pallidus and excitation in the thalamus
    c. Inhibition in the globus pallidus and excitation in the thalamus
    d. Inhibition in the globus pallidus and inhibition in the thalamus
    e. No effects in the globus pallidus or the thalamus

Answer 42

C

Question 43

46. Which human pathology has been linked to degeneration of the basal ganglia?
    a. Alzheimer’s disease
    b. Amyotrophic lateral sclerosis
    c. Multiple sclerosis
    d. Parkinson’s disease
    e. Retrograde amnesia

Answer 43

D

Question 44

47. Movement disorders such as Parkinson’s disease and Huntington’s disease are associated with degeneration in what areas of the central nervous system?
    a. The frontal cortex
    b. The primary motor cortex
    c. Spinal motor neurons
    d. The medulla oblongata
    e. The basal ganglia

Answer 44

E

Question 45

48. What experimental evidence indicates that the decision to perform a voluntary movement originates in the association cortex?
    a. A localized electrical potential in the association cortex is the first electrical signal recorded prior to a motion.
    b. Diffuse readiness potentials can be recorded over most of the cortical surface prior to the localized potentials that precede movement.
    c. Lesions of specific locations in the association cortex correspond to deficits in movement of corresponding body parts.
    d. Specific neurons in the association cortex are synaptically connected to corresponding spinal motor neurons.
    e. Animals with superior motor coordination have significantly larger association cortices than other animals.

Answer 45

B

Question 46

49. The motor cortex sends output to the cerebellum as movements are initiated, and the cerebellum
    a. transmits output from the motor cortex to the spinal motor neurons.
    b. transmits output from the motor cortex to the muscle fibers.
    c. transmits output from the motor cortex to the frontal cortex.
    d. compares sensory feedback to the initial motor output to detect errors.
    e. generates the readiness potential that precedes movement.

Answer 46

D

Question 47

50. A 66-year-old man has difficulty controlling voluntary movements. He can clearly state what he intends to do, describe how he would do it, and initiate or stop the movement. However, he has poor coordination and often misses his target. If his difficulty arises from a defect in one particular area of the central nervous system, which area is most likely to be involved?
    a. Association cortex
    b. Primary motor cortex
    c. Muscle spindles
    d. Spinal motor neurons
    e. Spinocerebellum

Answer 47

E

Question 48

1. Invertebrates have often been used in motor control studies because
   a. invertebrates have many more motor neurons in a single pathway compared to vertebrates.
   b. individual neurons are simpler in invertebrates than in vertebrates, and therefore motor control pathways are also simpler.
   c. motor control pathways in invertebrates are all reflex pathways and therefore are simpler than they are in vertebrates.
   d. only a few neurons are often involved in a particular step in an invertebrate motor control pathway.
   e. invertebrates can be trained more easily than vertebrates to perform specified motor tasks.

Answer 48

D

Question 49

2. The 1a afferent fibers associated with muscle spindles increase their action potential frequency only when the muscle
   a. shortens involuntarily.
   b. shortens more than expected during a voluntary contraction.
   c. shortens involuntarily or shortens more than expected during a voluntary contraction.
   d. lengthens involuntarily or shortens less than expected during a voluntary contraction.
   e. lengthens involuntarily.

Answer 49

D

Question 50

3. When your family physician taps your left patellar tendon with a mallet, stretch is sensed by sensory receptors
   a. associated with extrafusal fibers in the patellar tendon.
   b. associated with intrafusal fibers in the patellar tendon.
   c. associated with extrafusal fibers in the quadriceps.
   d. associated with intrafusal fibers in the quadriceps.
   e. in the brain.

Answer 50

D

Question 51

4. Which of the following illustrates the principle of convergence?
   a. A single muscle spindle afferent stimulates a single spinal motor neuron.
   b. A single pain receptor afferent stimulates a single spinal interneuron.
   c. Each motor neuron receives input from thousands of synapses.
   d. A single muscle spindle afferent stimulates many motor neurons.
   e. Each motor neuron receives input that has passed through multiple synapses on its way from the CNS.

Answer 51

C

Question 52

5. If you accidentally grab a very hot frying pan with your right hand, _______ will _______ action potential frequency.
   a. α motor neurons innervating the right elbow extensors; increase
   b. α motor neurons innervating the left elbow extensors; decrease
   c. α motor neurons innervating the right elbow flexors; increase
   d. afferent neurons from the Golgi tendon organ in the right elbow extensors; increase
   e. afferent neurons from the intrafusal fibers of the right elbow flexors; increase

Answer 52

C

Question 53

6. Suppose that you contract your biceps brachii muscle to toss a juggling pin into the air and find that it is much lighter than you expected. Which of the following will happen in compensation?
   a. Afferent neurons from the intrafusal fibers in the biceps brachii will increase their action potential frequency.
   b. The action potential frequency in the α motor neurons to the biceps brachii will be increased reflexively.
   c. The action potential frequency in the α motor neurons to the biceps brachii will be decreased reflexively.
   d. The action potential frequency in the γ motor neurons to the biceps brachii will be increased reflexively.
   e. The action potential frequency in the γ motor neurons to the biceps brachii will be decreased reflexively.

Answer 53

C

Question 54

7. Which of the following experimental results would demonstrate most strongly that sensory feedback is important in the control of rhythmic movement?
   a. A decerebrate cat (in which a portion of the brain has been removed) can walk and run on a treadmill.
   b. A decerebrate cat (in which a portion of the brain has been removed) is incapable of walking or running on a treadmill.
   c. An insect in which sensory afferents from the wings have been cut can fly.
   d. Repetitive stimulation of sensory afferents can alter the frequency of wingbeats in a tethered insect.
   e. Repetitive stimulation of sensory afferents cannot alter the frequency of wingbeats in a tethered insect.

Answer 54

D

Question 55

8. Which of the following statements about a network oscillator is true?
   a. One or more neurons receive input that turns the network on, and then neurons interact to generate a rhythmic output pattern.
   b. A pacemaker cell outside of the network turns the network on and off to control other effectors such as muscle fibers.
   c. Each cell in the network has pacemaker properties that determine the rate of output from the network.
   d. The cells in the network depolarize in response to input from sensory afferents.
   e. Membrane potentials of the neurons in the network increase and decrease simultaneously.

Answer 55

A

Question 56

9. Which of the following statements about the stomatogastric ganglion of a crayfish (which functions as a hybrid oscillator) is true?
   a. The central nervous system sends output that depolarizes each cell in the ganglion simultaneously.
   b. The central nervous system sends a depolarizing signal that begins each wave of depolarization.
   c. A rhythm generated by a cellular oscillator is reinforced and stabilized by network properties.
   d. A cellular oscillator generates rhythmic output under the control of a network of ganglionic cells.
   e. The rate of stomatogastric ganglion output is completely independent of the CNS.

Answer 56

C

Question 57

10. Compared to the repetitive motor patterns of locomotion, more complex motor behaviors
    a. probably involve many more spinal motor neurons in each step.
    b. probably rely on mechanisms that are completely different from those involved in locomotion.
    c. may be composed of simple patterns linked by CNS commands and responses to sensory feedback.
    d. involve similar patterns within the CNS but different output pathways to the skeletal muscles.
    e. are easier to study because each distinct movement making up the behavior happens only once.

Answer 57

C

Question 58

11. Experiments in which sensory afferent fibers in the hindlimbs of cats are transected show that sensory feedback from the limbs
    a. is necessary to maintain repetitive movements.
    b. is not necessary to maintain repetitive movements.
    c. has no role in cat locomotion.
    d. is necessary to initiate locomotor movements.
    e. normally acts to inhibit limb muscle contractions.

Answer 58

B

Question 59

12. Modeling experiments on walking and swimming in robotic salamanders have yielded which of the following conclusions?
    a. Walking and swimming are completely distinct motor patterns involving separate central pattern generators.
    b. Walking and swimming rely on precisely the same limb movements and timing.
    c. Walking and swimming use the same central pattern generator and timing, but the output goes to different muscle groups for each mode of locomotion.
    d. Walking or swimming movements can be generated automatically by a network of central pattern generators responding to the intensity of the central command.
    e. Walking or swimming movements are generated from a single central pattern generator responding to the sensory feedback received by the salamander.

Answer 59

D

Question 60

13. Pyramidal cells are
    a. neurons in the primary motor cortex that send output to activate spinal motor neurons.
    b. neurons in the cerebellum that send the sole output from the cerebellar cortex.
    c. neurons in the cerebellum that exert excitatory effects on other cerebellar neurons.
    d. motor neurons whose axons activate muscle fibers.
    e. sensory neurons that collect information on joint position and muscle length.

Answer 60

A

Question 61

14. In vertebrates, the highest-level planning of voluntary movement, such as deciding whether or not to make a movement, begins in the
    a. association cortex.
    b. basal ganglia.
    c. cerebellar cortex.
    d. primary motor cortex.
    e. striatum.

Answer 61

A

Question 62

15. The Purkinje cells of the cerebellum send _______ output from the cerebellar cortex to _______.
    a. excitatory; the cerebellar nuclei
    b. inhibitory; the cerebellar nuclei
    c. excitatory; the spinal cord
    d. inhibitory; the spinal cord
    e. excitatory; other cells in the cerebellar cortex

Answer 62

B

Question 63

16. Studies of the circuitry and function of the vertebrate cerebellum have resulted in
    a. a detailed map of the representation of individual muscles in the cerebellar cortex, as well as functional details of how the neurons interact to coordinate movement.
    b. a detailed map of the representation of individual muscles in the cerebellar cortex, although there is still some uncertainty about the function of the different neurons.
    c. a detailed explanation of how different categories of neurons interact to coordinate movement, but no spatial map.
    d. a detailed explanation of how the cerebellum functions in humans, but not in other vertebrates.
    e. several competing models of how the cerebellum might work to coordinate movement.

Answer 63

E

Question 64

17. Voluntary movements of a vertebrate animal are generated by
    a. the motor cortex.
    b. the cerebellum.
    c. the spinal cord.
    d. basal ganglia.
    e. interactions of several regions.

Answer 64

E

Question 65

18. How does the indirect pathway of synaptic transmission in the basal ganglia help to fine tune voluntary movement?
    a. The indirect pathway sends the signals that activate thalamic neurons associated with the intended movement.
    b. The indirect pathway inhibits thalamic neurons, thereby suppressing movements that may compete with the intended movement.
    c. The indirect pathway inhibits thalamic neurons, thereby modulating muscular force so that movements are not too forceful.
    d. The indirect pathway reinforces the direct pathway so that thalamic neurons stimulate the motor cortex at higher frequency.
    e. The indirect pathway excites thalamic neurons whereas the direct pathway excites spinal motor neurons directly.

Answer 65

B

Question 66

19. According to the current general model describing planning and execution of a voluntary movement, decisions generated in the _______ cortex are passed to the _______ via the _______.
    a. motor; association cortex; cerebellum
    b. association; motor cortex; basal ganglia
    c. association; cerebellum; basal ganglia
    d. frontal; basal ganglia; motor cortex
    e. motor; basal ganglia; motor neurons

Answer 66

B

Question 67

20. A 52-year-old woman has difficulty initiating voluntary movements. She can clearly state what she intends to do, describe exactly how she would do it, and picture herself doing it easily. When she is able to begin the motion, she can complete it smoothly and accurately, but she has difficulty beginning the motion. If the difficulty arises from a defect in one particular area of the nervous system, which area is most likely to be involved?
    a. Association cortex
    b. Basal ganglia
    c. Muscle spindles
    d. Spinal motor neurons
    e. Spinocerebellum

Answer 67

B