Chapter 8: Sensorimotor System

Question 1

sensory vs motor pathways

Answer 1

sensory pathways are afferent (go to the brain)
motor pathways are efferent (come from the brain)

Question 2

where does a motor sequence start and stop?

Answer 2

starts in the cortex and terminates in muscle fibres of the PNS

Question 3

what is the purpose of the premotor cortex?

Answer 3

organizes movement sequences

Question 4

what is the purpose of the prefrontal cortex?

Answer 4

plans movements

Question 5

what is the purpose of the motor cortex?

Answer 5

outer strip of the brain that includes a map of the body and produces specific movements
part of a feedback loop with the basal ganglia

Question 6

what kind of neurons are located in the motor cortex?

Answer 6

upper motor neurons

Question 7

what do the caudate nucleus and putamen form?

Answer 7

form the walls of ventricles and the striatum

Question 8

what is the purpose of the striatum?

Answer 8

habitual movements

Question 9

what is the purpose of the globus pallidus?

Answer 9

processes how much force is needed (volume control)

Question 10

what causes Parkinson’s disease?

Answer 10

a loss of dopaminergic neurons in the substantia nigra

Question 11

what are some common symptoms of Parkinson’s disease?

Answer 11

hyperkinetic (unwanted) movements, hypokinetic symptoms (inability to move), resting tremor

Question 12

what are the symptoms of Huntington’s disease?

Answer 12

erratic functioning, cognitive and motor decline

Question 13

what is MPTP?

Answer 13

a neurotoxin used to model Parkinson’s disease in rodent models. rapidly kills dopaminergic neurons in the substantia nigra (within 24 hours)

Question 14

what does dysfunction in the basil ganglia sometimes lead to?

Answer 14

obsessive-compulsive behaviours

Question 15

how to axons of upper motor neurons descend to the brainstem?

Answer 15

via the internal capsule

Question 16

what do the corticobulbar tracts control?

Answer 16

movement of the head, face, mouth

Question 17

what do the corticospinal tracts control?

Answer 17

arms, legs, other parts of the body

Question 18

what is the purpose of the cerebellum in movement sequences?

Answer 18

timing and flow, and accuracy and error correction

Question 19

where do the corticobulbar tracts synapse?

Answer 19

lower motor neurons in the brainstem (cranial nerves and face and neck muscles)

Question 20

what is the function of the lateral corticospinal tract?

Answer 20

moves limbs and digits

Question 21

what is the function of the anterior corticospinal tract?

Answer 21

moves muscles at the body’s midline

Question 22

what occurs on the anterior root of the spinal cord?

Answer 22

motor signals travel down it and exit on different parts of the spinal cord

Question 23

what is the purpose of the posterior root of the spinal cord?

Answer 23

receives sensory signals that travel up to the brain

Question 24

what is responsible for the exteroceptive sense?

Answer 24

the skin

Question 25

what are some examples of exteroceptive senses?

Answer 25

feeling things on the skin, temperature changes, damage to the skin

Question 26

what is the proprioceptive sense?

Answer 26

where your limbs are in space

Question 27

what are interoceptive senses?

Answer 27

has to do with the autonomic nervous system (organs, blood pressure, etc)

Question 28

what are merkel receptors?

Answer 28

touch receptors that are close to the surface of the skin and are all over the body

Question 29

what are ruffini corpuscles?

Answer 29

corpuscles that are located low down in the skin and respond to stretching of the skin

Question 30

what are pacinian corpuscles?

Answer 30

layered and filled with fluid, respond to deep vibrations of the skin

Question 31

what are free nerve endings?

Answer 31

pain receptors close to the surface of the skin and respond to pain and temperature changes

Question 32

what are the procedure for determining the two-point threshold?

Answer 32

slowly bring two points closer together until the person only feels one point (sensitivity threshold)
the lower the threshold, the more sensitive the body part is

Question 33

what do highly sensitive areas contain?

Answer 33

a higher density of merkel receptors

Question 34

what are CT mechanoreceptors?

Answer 34

receptors wrapped around the roots of fine hairs and respond to their movement

Question 35

what are the three general categories of pain?

Answer 35

nociceptive
inflammatory
neuropathic

Question 36

nociceptive pain

Answer 36

sharp pain against the skin and temperature changes

Question 37

inflammatory pain

Answer 37

response to red, inflamed skin

Question 38

neuropathic pain

Answer 38

lingering pain after the initial injury

Question 39

what are the two dimensions of pain?

Answer 39

affective and discriminative

Question 40

affective dimension of pain

Answer 40

the emotional aspect; typically negative/emotionally upsetting

Question 41

discriminative dimension of pain

Answer 41

where the pain is coming from

Question 42

where is pain processed?

Answer 42

in the pain matrix

Question 43

which structures make up the pain matrix?

Answer 43

parietal (somatosensory), prefrontal (decision making), limbic (emotional quality)

Question 44

traditional theory of pain

Answer 44

sensation of pain is explained in purely physiological terms

Question 45

what are the issues associated with the traditional theory of pain?

Answer 45

can’t explain why placebos work for some people and can’t explain how people continue playing a sport after being injured without feeling the pain