mc for exam 2

Question 1

1. Motor neurons with cell bodies in the cerebral cortex or the brainstem are part of which motor system?
   a. Lower motor neurons
   b. Upper motor neurons
   c. Both lower and upper motor neurons
   d. Cerebellum
   e. Basal ganglia

Answer 1

b. Upper motor neurons

Question 2

2. Ava notices that when she consumes two alcoholic beverages within an hour she has trouble controlling her movements. She stumbles occasionally and may knock over a glass that she intended to pick up. She doesn’t have any trouble initiating movement, but all of her movements seem a little “off.” Which motor system is most affected by Ava’s alcohol consumption?
   a. Lower motor neurons
   b. Upper motor neurons
   c. Both lower and upper motor neurons
   d. Cerebellum
   e. Basal ganglia

Answer 2

d. Cerebellum

Question 3

3. Huntington’s disease and Parkinson’s disease indicate the importance of which motor system for proper motor functioning?
   a. Lower motor neurons
   b. Upper motor neurons
   c. Both lower and upper motor neurons
   d. Cerebellum
   e. Basal ganglia

Answer 3

e. Basal ganglia

Question 4

4. _______ innervate striated muscle fibers, and _______ innervate specialized fibers called _______.
   a. γ motor neurons; α motor neurons; muscle spindles
   b. α motor neurons; γ motor neurons; muscle spindles
   c. α motor neurons; γ motor neurons; extrafusal muscle fibers
   d. γ motor neurons; α motor neurons; intrafusal muscle fibers
   e. α motor neurons; γ motor neurons; extrafusal muscle fibers

Answer 4

b. α motor neurons; γ motor neurons; muscle spindles

Question 5

5. As motor unit size increases, which property of the α motor neuron decreases?
   a. Excitability
   b. Cell body size
   c. Dendritic complexity
   d. Axonal diameter
   e. Number of axonal branches

Answer 5

a. Excitability

Question 6

6. While helping a friend move, you hold out your arms to take a box from your friend. To ensure that you do not drop the box, your _______ neurons send a signal to your _______ neurons to contract your biceps and relax your triceps.
   a. group Ia afferent; α motor
   b. group II afferent; α motor
   c. α motor; group Ia afferent
   d. group Ia afferent; γ motor
   e. group II afferent; γ motor

Answer 6

a. group Ia afferent; α motor

Question 7

7. Which part of the lower motor neuron circuit prevents muscles from generating excessive tension and maintains steady muscle tone during muscle fatigue?
   a. Muscles spindles
   b. α motor neurons
   c. Golgi tendon organs
   d. Reciprocal innervation
   e. γ motor neurons

Answer 7

c. Golgi tendon organs

Question 8

8. As a person squats, the quadriceps muscles contract. At the same time, the respective Golgi tendon organs _______ their firing rate, and the intrafusal muscle fibers _______ their firing rate.
   a. increase; increase
   b. increase; decrease
   c. decrease; decrease
   d. decrease; increase
   e. decrease; level off

Answer 8

b. increase; decrease

Question 9

9. The local circuits in the spinal cord that are fully capable of controlling the timing and coordination of complex locomotion are called
   a. central pattern generators.
   b. the mesencephalic locomotor region.
   c. the flexion-crossed extension reflex.
   d. reciprocal innervation.
   e. motor units.

Answer 9

a. central pattern generators.

Question 10

10 Golgi tendon organs are most sensitive to
a. muscle tension.
b. muscle stretch.
c. absolute joint position.
d. muscle contraction frequency.
e. muscle fatigue.

Answer 10

a. muscle tension.

Question 11

11. Lower motor neurons responsible for posture and locomotion are found in the _______ and primarily receive input from upper motor neurons in the _______.
    a. medial ventral horn; brainstem
    b. lateral ventral horn; brainstem
    c. medial ventral horn; cerebral cortex
    d. lateral ventral horn; cerebral cortex
    e. medial dorsal horn; brainstem

Answer 11

a. medial ventral horn; brainstem

Question 12

12. Upper motor neurons in the cerebral cortex are located in which lobe(s) of the brain?
    a. Frontal
    b. Parietal
    c. Temporal
    d. Occipital
    e. Municipal

Answer 12

a. Frontal

Question 13

13. The pyramidal cells of the primary motor cortex are located in which cortical layer?
    a. 1
    b. 2
    c. 3
    d. 5
    e. 6

Answer 13

d. 5

Question 14

14. The lateral corticospinal tract innervates α motor neurons that are important for which task?
    a. Vision
    b. Posture
    c. Writing
    d. Walking
    e. Coughing

Answer 14

c. Writing

Question 15

15. In humans, which of the following body areas listed has the greatest area of motor cortex devoted to it?
    a. Neck
    b. Lips
    c. Chest
    d. Knee
    e. Brow

Answer 15

b. Lips

Question 16

16. Which evidence suggests that upper motor neurons in the primary cortex have a preferred direction (vector)?
    a. Spike-triggered averaging indicates that a single upper motor neuron activates a muscle field.
    b. Stimulation of the primary motor cortex can elicit movements in different areas of the body.
    c. Firing rates of upper motor neurons change prior to movements involving small forces.
    d. Mapping of the primary motor cortex indicates that many body regions overlap.
    e. The firing rate of a particular upper motor neuron is highest when the hand moves from left to right.

Answer 16

e. The firing rate of a particular upper motor neuron is highest when the hand moves from left to right.

Question 17

17. What is the name of the neurons that fire when an animal observes and performs a goal-oriented task?
    a. Medullary pyramids
    b. Broca’s neurons
    c. Reticular formation
    d. Betz cells
    e. Mirror neurons

Answer 17

e. Mirror neurons

Question 18

18. The area of the brain dedicated to speech production is
    a. premotor cortex.
    b. intraparietal sulcus.
    c. Broca’s area.
    d. Brodmann’s area.
    e. Wernicke’s area.

Answer 18

c. Broca’s area.

Question 19

19. A person with damage to the direct motor pathway but an intact indirect motor pathway, would have the most difficulty
    a. walking.
    b. typing.
    c. running.
    d. standing.
    e. swimming.

Answer 19

b. typing.

Question 20

20. Which statement about primary motor cortex neurons is false?
    a. The firing of primary motor cortical neurons occurs precisely at the onset of a muscle contraction.
    b. Primary motor cortical neurons can be directionally selective.
    c. The firing rate of a primary motor cortical neuron codes for or contributes to the force of a movement. d. The directional control of a movement is coded by the activity of a population of primary motor cortical neurons.
    e. The directional responses of primary motor cortical pyramidal cells tend to be broadly tuned in that they respond over a somewhat broad range of movement directions.

Answer 20

a. The firing of primary motor cortical neurons occurs precisely at the onset of a muscle contraction.

Question 21

21. Which statement about directional tuning and population coding by primary motor cortical neurons is true?
    a. The precision of directional motor movements equals the precision of directional tuning of individual primary motor cortical pyramidal cells.
    b. Most primary motor cortical neurons have two or three distinct, preferred directions separated by intervening ranges of non-preferred directions.
    c. The vector summation of population responses of primary motor cortical neurons is important for directional control of motor movements.
    d. Every possible direction of motion is made possible by specific populations of primary motor cortical neurons that are tuned specifically to each of the possible directions.
    e. Primary motor cortical neurons do not code direction.

Answer 21

c. The vector summation of population responses of primary motor cortical neurons is important for directional control of motor movements.

Question 22

22. Which pair of nuclei comprise the striatum?
    a. Globus pallidus and caudate
    b. Putamen and pallidum
    c. Caudate and substantia nigra
    d. Putamen and caudate
    e. Subthalamic nucleus and substantia nigra

Answer 22

d. Putamen and caudate

Question 23

23. Where are medium spiny neurons located?
    a. Striatum
    b. Pallidum
    c. Globus pallidus
    d. Substantia nigra pars compacta
    e. Subthalamic nucleus

Answer 23

a. Striatum

Question 24

24. Output from the basal ganglia projects from which two structures?
    a. Globus pallidus and caudate
    b. Putamen and pallidum
    c. Globus pallidus and substantia nigra pars reticulata
    d. Putamen and caudate
    e. Caudate and substantia nigra pars compacta

Answer 24

c. Globus pallidus and substantia nigra pars reticulata

Question 24

4. Which regions of the cerebral cortex project directly to the striatum?
   a. Frontal cortex
   b. Temporal lobe
   c. Insular cortex
   d. Cingulate cortex
   e. Nearly all regions of the cerebral cortex

Answer 24

e. Nearly all regions of the cerebral cortex

Question 25

25. Dopaminergic neurons that synapse on medium spiny neurons originate from which brain region?
    a. Substantia nigra pars reticulata
    b. Pallidum
    c. Globus pallidus
    d. Substantia nigra pars compacta
    e. Subthalamic nucleus

Answer 25

d. Substantia nigra pars compacta

Question 26

26. The external segment of the globus pallidus projects to the internal segment and the _______ in the _______ pathway.
    a. subthalamic nucleus; direct
    b. caudate; direct
    c. subthalamic nucleus; indirect
    d. caudate; indirect
    e. VA/VL complex of the thalamus; indirect

Answer 26

c. subthalamic nucleus; indirect

Question 27

27. Both D1 and D2 receptors are _______, with D1 receptors _______ cAMP and D2 receptors _______ cAMP.
    a. metabotropic; decreasing; increasing
    b. metabotropic; increasing; decreasing
    c. metabotropic; increasing; maintaining
    d. ionotropic; decreasing; increasing
    e. ionotropic; increasing; decreasing

Answer 27

b. metabotropic; increasing; decreasing

Question 28

28. While visiting a distant uncle, you notice that his face seems “mask-like” and that he shuffles when he walks, and his shoulders are stooped. Based on these symptoms, which condition would you suspect that your uncle had?
    a. Huntington’s disease
    b. Parkinson’s disease
    c. Alzheimer’s disease
    d. Multiple sclerosis
    e. Muscular dystrophy

Answer 28

b. Parkinson’s disease

Question 29

29. Deep brain stimulation is a potential treatment for advanced Parkinson’s disease. Which brain region is one of the most common targets for DBS treatment?
    a. Frontal cortex
    b. Subthalamic nucleus
    c. Caudate
    d. Substantia nigra pars compacta
    e. VA/VL complex of the thalamus

Answer 29

b. Subthalamic nucleus

Question 30

30. The basal ganglia are thought to elicit movement via
    a. direct excitation of the primary motor cortex.
    b. direct excitation of the premotor cortex.
    c. disinhibition of thalamic neurons (VA/VL).
    d. direct excitation of thalamic neurons (VA/VL).
    e. excitatory projections from the subthalamic nucleus to higher-order association areas of cortex.

Answer 30

c. disinhibition of thalamic neurons (VA/VL).

Question 31

31. Parkinson’s disease is associated with loss of
    a. dopamine neurons that project to the striatum, leading to a hypokinetic disorder.
    b. glutamatergic neurons in the thalamus that project to the motor cortex, leading to a hypokinetic disorder. c. dopamine neurons in the subthalamic nuclei, leading to a hyperkinetic disorder.
    d. input from the cerebral cortex to the striatum, leading to a hyperkinetic disorder.
    e. dopamine neurons in the caudate, leading to a hypokinetic disorder.

Answer 31

a. dopamine neurons that project to the striatum, leading to a hypokinetic disorder.

Question 32

32. Which of the following is a major function of the cerebellum?
    a. Alter local circuits of the brainstem and spinal cord via direct projections to the lower motor neurons
    b. Analyze errors between intended motor output and actual motor output
    c. Modulate the output of the basal ganglia
    d. Relay information from the primary somatosensory cortex to the primary motor cortex
    e. Modulate and relay executive decision-making information from the prefrontal cortex to the rest of the cerebral cortex

Answer 32

b. Analyze errors between intended motor output and actual motor output

Question 33

33. What cell type does not have direct contact with Purkinje cells?
    a. Granule cells
    b. Climbing fibers
    c. Mossy fibers - synapse on granule cells/DCN
    d. Deep cerebellar nuclear cells
    e. Basket cells

Answer 33

c. Mossy fibers - synapse on granule cells/DCN

Question 34

34. Which cell type carries the main output from the cerebellar cortex and is considered the prime computational element of the cerebellum?
    a. Purkinje
    b. Granule
    c. Golgi
    d. Basket
    e. Stellate

Answer 34

a. Purkinje

Question 35

35. Which structure does not receive input from the cerebellar cortex?
    a. Dentate nucleus
    b. Interposed nucleus
    c. Fastigial nucleus
    d. Red nucleus
    e. Vestibular nucleus

Answer 35

d. Red nucleus

Question 36

36. Cerebellar ataxia is characterized by
    a. difficulty with initiating movements.
    b. an inability to perform goal-directed movements.
    c. an inability to perform complex sequences of movements.
    d. jerky, imprecise movements.

Answer 36

d. jerky, imprecise movements.