Deck 6: The Sensorimotor System

Question 1

The brain recognizes action potentials from different sensory modalities as separate and distinct because

A) action potentials from different sensory modalities are carried on different nerve tracts.
B) the volley of action potentials differs for each sensory modality.
C) action potentials from different sensory modalities utilize different neurotransmitter systems.
D) action potentials from different sensory modalities are processed through different frontal lobe regions.

Answer 1

A

Question 2

_______ are sparsely located throughout the skin and respond to stretching of fingers and limbs.

A) Meissner's corpuscles
B) Pacinian corpuscles
C) Merkel's discs
D) Ruffini corpuscles

Answer 2

D

Question 3

Vibration of _______ stretches the neuronal membrane, allowing sodium channels to open and graded receptor potentials to occur.

A) free nerve endings
B) Pacinian corpuscles
C) Merkel's discs
D) Ruffini's corpuscles

Answer 3

B

Question 4

The receptor potential produced by a Pacinian corpuscle in response to mechanical stimulation is

A) all-or-none.
B) hyperpolarizing.
C) proportional to stimulus intensity.
D) not affected by stimulus intensity.

Question 5

Which receptor types would be most useful for reading Braille?

A) Pacinian corpuscles
B) Free nerve endings
C) Ruffini corpuscles
D) Merkel's discs

Question 6

The onion-like receptor found in skin that selectively responds to vibration and pressure is the

A) Ruffini corpuscle.
B) Pacinian corpuscle.
C) Meissner's corpuscle.
D) Merkel's disc.

Question 7

The _______ of a sensory neuron is the stimulus region that causes the cell to alter its firing rate.

A) receptive field
B) adaptative field
C) modulatory region
D) phasic-tonic region

Question 8

Which statement about the receptive field of a sensory neuron on skin is true?

A) All receptive fields of sensory nerves are excitatory.
B) Receptive fields of sensory neurons have a characteristic shape with excitatory and inhibitory regions.
C) Receptive fields of sensory neurons differ in size and shape, but all respond to the same type and quality of stimulation.
D) Receptive fields of skin sensory neurons are either excitatory or inhibitory.

Question 9

Receptors that show little or no adaptation to maintained stimulation are called _______ receptors.

A) photic
B) phasic
C) tonic
D) clonic

Question 10

Which statement best reflects the evolutionary advantage of sensory adaptation?

A) It prevents fatigue of sensory receptors.
B) It prevents the constant excitation of the hairs of your skin by your clothing.
C) It prevents the nervous system from being overwhelmed by stimuli that offer very little information about the world.
D) It allows the brain to reassign sensory cortex in people who lose a limb.

Question 11

On entering the spinal cord, the somatosensory projections ascend through the _______ system.

A) primary cortical
B) dorsal column
C) spinothalamic
D) anterolateral

Question 12

Which body part is not highly represented on the sensory homunculus?

A) Fingers
B) Lips
C) Hands
D) Eyes

Question 13

Plasticity of somatosensory cortical maps is evident following

A) musical training.
B) limb amputation in adults.
C) surgical transplant of a hand.
D) All of the above

Question 14

The band of the skin that is innervated by a single spinal nerve is called a

A) polymodal strip.
B) dorsal column.
C) dermatome.
D) cutaneous segment.

Question 15

Professional musicians who play string instruments have expanded cortical representations of their _______.

A) right fingers
B) left fingers
C) lips
D) torso

Question 16

S1 is located in the

A) central sulcus.
B) precentral gyrus.
C) postcentral gyrus.
D) occipital lobe.

Question 17

_______ neurons are very active in people with synesthesia.

A) Polymodal
B) Dorsal
C) Visual
D) Nonprimary

Question 18

Which of the following is an example of synesthesia?

A) Envisioning bright fireworks whenever you hear Mozart
B) Going to a movie by yourself
C) Getting upset when you forget an appointment
D) Remembering a conversation word for word

Question 19

Some species of snakes are sensitive to

A) ultrasonic sounds.
B) radio-frequency signals.
C) infrared energy.
D) GPS signals.

Question 20

According to the McGill Pain Questionnaire, describing a "shooting" pain in your arm uses which dimension(s) of pain?

A) Motivational-affective
B) Cognitive-evaluative
C) Sensory-discriminative
D) Situational-interpretive

Question 21

Which molecule is involved in pain pathways in the spinal cord?

A) Acetylcholine
B) Substance P
C) GABA
D) Nitrous oxide

Question 22

The painful sensations induced by capsaicin are mediated by _______ receptors.

A) TRPV1
B) TRPM3
C) substance P
D) TRP2

Question 23

Thin, unmyelinated _______ fibers conduct pain information via the anterolateral system slowly.

A) Aα
B) Aδ
C) C
D) beta

Question 24

Mice that lack substance P exhibit

A) total insensitivity to pain stimuli.
B) insensitivity to mildly painful stimuli but normal responses to intensely painful stimuli.
C) insensitivity to intensely painful stimuli but normal responses to mildly painful stimuli.
D) exaggerated responses to mildly painful stimuli.

Question 25

Pain-induced release of substance P in the dorsal horn of the spinal cord causes

A) remodeling of pain pathway neurons.
B) a temporary blockade for subsequent pain signals.
C) increased production of acetylcholine receptors, which improves pain suppression by the brain.
D) reduction of endogenous opiate secretion, allowing for important pain stimuli to reach the brain.

Question 26

One possibility for opioid mechanism is that action in the _______ causes descending fibers from the brainstem to directly inhibit dorsal horn cells that transmit _______ information.

A) periaqueductal gray; pain
B) somatosensory cortex; vibration
C) thalamus; heat
D) pons; light touch

Question 27

Afferent fibers from the periphery that carry nociceptive information terminate on neurons in the

A) dorsal horn cells of the spinal cord.
B) medulla.
C) central brainstem.
D) ventral horn cells of the spinal cord.

Question 28

Information about pain and temperature in the anterolateral system crosses the midline at the level of the

A) cerebral cortex.
B) thalamus.
C) medulla.
D) spinal cord.

Question 29

A delta (A $\delta$ ) fibers can rapidly transmit pain information to the brain because

A) they have the shortest axons.
B) they are unmyelinated.
C) they have large-diameter axons.
D) they have small-diameter axons.

Question 30

What part of the CNS integrates pain information?

A) Medulla
B) Parietal cortex
C) Cingulate cortex
D) Sensorimotor cortex

Question 31

In the mirror treatment of phantom limb pain, the visual illusion

A) acts to relax and comfort the amputee.
B) tricks the brain into thinking it is controlling the amputated limb.
C) focuses attention away from the pain.
D) puts the amputee into a hypnotic state.

Question 32

Which statement about the use of morphine to relieve surgical pain is true?

A) Although morphine is addictive, the risk of addiction when it is used to relieve surgical pain is estimated to be less than 1%.
B) Because morphine is highly addictive, it is not generally prescribed to manage severe pain.
C) Morphine relieves surgical pain by binding to endogenous cannabinoid receptors.
D) Over-the-counter medications are just as effective as morphine for treating severe pain.

Question 33

Cannabis reduces pain by

A) stimulating endogenous cannabinoid receptors in the spinal cord and brain.
B) suppressing endogenous cannabinoid receptors in the spinal cord and brain.
C) stimulating endogenous cannabinoid receptors in the spinal cord only.
D) suppressing endogenous cannabinoid receptors in the spinal cord only.

Question 34

The pain control procedure in TENS is based on

A) mechanical stimulation of the skin.
B) electrical stimulation of the skin.
C) the administration of drugs.
D) hypnotic suggestion and placebo effect.

Question 35

It is thought that TENS may affect pain relief by causing release of endogenous opioids because naloxone

A) enhances the analgesic action of TENS.
B) inhibits the inflammation associated with TENS.
C) reduces the analgesic effect of TENS.
D) has no effect on TENS.

Question 36

It is thought that acupuncture relieves pain by

A) blocking the pain signals in the spinal cord.
B) altering the brain's perception of pain.
C) blocking pain signals to the brain.
D) activating endogenous opioids and through the placebo effect.

Question 37

Naloxone (Narcan), which is used to revive people who are dying of opioid overdose, is an opioid

A) agonist.
B) antagonist.
C) COX-1 inhibitor.
D) COX-2 inhibitor.

Question 38

EMG studies have revealed that a voluntary movement of the arm, for example, when asked to pull a lever, 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.

Question 39

Nervous system motor plans must balance a trade-off between

A) speed and accuracy.
B) complexity and accuracy.
C) complexity and force.
D) force and precision.

Question 40

Just prior to voluntarily moving of the arms, for example, to pull a lever, a person will adjust their _______. This is an example of _______.

A) posture; ataxia
B) legs; motor planning
C) torso; mirror neurons
D) eyes; proprioception

Question 41

Blocking _______ at the neuromuscular junction blocks a muscle _______.

A) norepinephrine; relaxation
B) dopamine; ataxia
C) acetylcholine; contraction
D) glutamate; tension

Question 42

The pyramidal motor system begins in the _______ cortex, and the pathway then travels to the _______ and then the _______.

A) parietal; thalamus; medulla
B) frontal; medulla; spinal cord
C) parietal; medulla; pons
D) frontal; thalamus; medulla

Question 43

The neurotransmitter _______ is produced and released by motor neurons to stimulate skeletal muscles.

A) dopamine
B) glutamate
C) serotonin
D) acetylcholine

Question 44

Motor neurons are referred to as the "final common pathway" because they are the

A) last motor neurons in a chain that actually innervates the muscle.
B) the only pathway by which the brain and spinal cord can control movement.
C) part of the dorsal motor system closest to the brainstem.
D) white matter of the spinal cord.

Question 45

Which receptor is likely to respond to an overload that threatens to tear muscles or ligaments?

A) Muscle spindle
B) Golgi tendon organ
C) Intrafusal fiber
D) All of the above

Question 46

Which receptor responds when you stretch your arm out to catch an object?

A) Muscle spindle
B) Golgi tendon organ
C) Intrafusal fiber
D) Dermatome

Question 47

Severing sensory fibers from a monkey's arm will cause the monkey to stop using that arm, but it will begin to use it again if the other (good) arm is restrained. This demonstrates that

A) primates will use a damaged limb if they have no alternative.
B) over time the cortex can train the limbs to respond.
C) proprioceptive information can be supplemented with feedback from other senses.
D) the sensory pathways are malleable after injury.

Question 48

Golgi tendon organs are to _______ as muscle spindles are to _______.

A) tension; stretch
B) stretch; tension
C) proprioception; paresis
D) paresis; proprioception

Question 49

Lesions of the extrapyramidal system typically interfere with spinal reflexes by

A) eliminating them.
B) exaggerating them.
C) temporarily blocking them.
D) causing seizure activity upstream in the cortex.

Question 50

Which statement about the primary motor cortex (M1) is true?

A) The motor homunculus is an accurate representation of M1.
B) M1 is under ipsilateral control.
C) Motor representations on M1 change with training.
D) Motor representations on M1 are static and do not change with training.

Question 51

Which statement about the primary motor cortex is false?

A) It is a major source of axons that form the pyramidal tract.
B) Many M1 cells have directional sensitivity.
C) Cortical maps of M1 show plasticity, changing with experience
D) It occupies a large part of the upper medulla.

Question 52

The _______ seems to be important in the initiation of movement sequences.

A) SMA
B) premotor cortex
C) M1
D) cerebellum

Question 53

The supplementary motor area and the premotor cortex are areas of

A) the parietal lobe.
B) association cortex.
C) nonprimary motor cortex.
D) the cerebellum.

Question 54

The SMA appears to be especially active

A) following the execution of reflexes.
B) during the control of movements that are internally generated.
C) during the control of movements that are externally generated.
D) following the completion of learned movements.

Question 55

Mirror neurons are especially interesting to researchers because

A) they appear to trigger specific movements.
B) they fire when a monkey sees another monkey (or human) performing a simple movement previously performed by the monkey itself.
C) they might be part of a neural system for empathy.
D) All of the above

Question 56

Some individuals born without a _______ still show normal motor skills.

A) cerebellum
B) hippocampus
C) cingulate
D) thalamus

Question 57

Parkinson's disease is linked to

A) degeneration of dopamine neurons of the substantia nigra.
B) destruction of the caudate and putamen.
C) decreased availability of serotonin.
D) atrophy of motor cortex.

Question 58

When athletes work out to improve their stamina, one of the goals is to enhance their

A) fast-twitch muscle fibers.
B) muscle spindles.
C) slow-twitch muscle fibers.
D) neural motor plans.

Question 59

According to the concept of _______, particular nerve cells in the brain recognize sensory information that is specific to only particular types of information.

Question 60

Plunging your hand into a bucket of cold water activates skin receptors called _______.

Question 61

A _______ is a skin receptor type that is especially sensitive to stretching of the skin.

Question 62

The adaptive significance of _______ pain receptors is to prevent ongoing injury.

Question 63

A person is suffering from acute pain and describes it to the doctor as "constant, dull throbbing." That description falls into the _______ dimension of the pain experience.

Question 64

Receptors with the initials _______ respond very high temperatures but do not respond to capsaicin, the chemical that makes chili peppers spicy hot.

Question 65

Lesions of the _______ system generally do not cause paralysis, but they usually exaggerate spinal reflexes.

Question 66

A neuron that fires shortly before an individual makes a specific movement and when they see another individual make the same movement is called a _______.

Question 67

The supplementary motor cortex and the premotor cortex together make up the _______ motor cortex.

Question 68

List and discuss the function of each of the different types of receptor cells found in the skin. Why do receptor cells types differ across species?

Question 69

What are tonic and phasic receptors and how are they related to sensory adaptation?

Question 70

Describe the receptive field of a somatosensory neuron. What happens when the patch of skin it innervates is stimulated?

Question 71

Outline the pathway of pain and temperature information to the cingulate cortex.

Question 72

Write a short paragraph using the following terms: opiates; endorphins, pain relief; TENS; placebo; acupuncture; naloxone.

Question 73

Differentiate the motor and sensory homunculi. What purpose does the odd-looking little character (called a homunculus) serve?

Question 74

Explain how motor neurons cause muscles to contract.

Question 75

What are Golgi tendon organs and what is their function?

Question 76

What are mirror neurons, and why do researchers find them so interesting?

Question 77

Write a short paragraph using the following terms: Extrapyramidal system; basal ganglia; cerebellum; ataxia; Parkinson's disease; Huntington's disease.

Question 78

Name four sensory receptors found in the skin and identify the stimuli to which each is sensitive.

Question 79

What is meant by "sensory adaptation," and what is its evolutionary significance?

Question 80

Provide a precise anatomical description of the major sensory projections from the periphery to the brain.