Chapter 11: Motor and Somatosensory

Question 1

Compare somatosensory and motor pathways as far as their direction and location in the spinal cord

Answer 1

Somatosensory = sensory, afferent, posterior
Motor = efferent, anterior

Question 2

What are the 4 main dermatomes and what part of the body do they relate to?

Answer 2

Cervical: arms
Thoracic: chest
Lumbar: Legs
Sacral: Bum and legs

Question 3

What is a motor sequence? What are they the base for argued by Lashley?

Answer 3

movement modules preprogrammed by brain and produced as a unit; the base for complex movement

Question 4

What 3 parts of the brain take part in initiating a motor sequence? What does each do?

Answer 4

Prefrontal cortex: plans our behavior and specifies a goal
Premotor cortex: organizes movement sequences; produces movement with many body parts
Primary motor cortex (M1): focal skilled movements

Question 5

What part of the brain is involved in species-typical movement? What are some qualities of these behaviors?

Answer 5

brainstem; they are innate and depend on context as well

Question 6

What does the motor cortex represent at the basic level?

Answer 6

fundamental movement categories

Question 7

Where is the supplementary motor cortex?

Answer 7

in the premotor area of the frontal lobe

Question 8

What is a corticospinal tract? What are the 2 and where do they branch off?

Answer 8

nerve fibres connecting cerebral cortex to the spinal cord; opposite-side lateral tract and same-side anterior tract; the brain stem

Question 9

What does the opposite side lateral tract inform movement of?

Answer 9

the limbs and digits

Question 10

What does the same-same anterior tract inform movement of?

Answer 10

the trunk

Question 11

Where do motor neurons send axons to body muscles?

Answer 11

in the anterior horn

Question 12

What are the 2 contraposing types of muscles?

Answer 12

extensor (away) and flexor (toward); work in opposition

Question 13

What is the basal ganglia composed of?

Answer 13

the caudate nucleus, putamen, globus pallidus and subthalamic nucleus

Question 14

What are the 3 connections involving the basal ganglia?

Answer 14

1) Neocortex + allocortex –> basal ganglia
2) basal ganglia –> thalamus –> motor cortex
3) substantia nigra basal ganglia

Question 15

What can damage to the putamen result in?

Answer 15

dyskinesias (twitching) or hyperkinetic and hypokinetic symptoms

Question 16

What acts as volume control in the basal ganglia, how?

Answer 16

globus pallidus; inhibited = movement vs excited = no movement

Question 17

What does the flocculus do in the cerebellum?

Answer 17

receives information from the middle ear for balance control and controls eye movements

Question 18

What cell type is in the 2nd layer of the cerebellum? What is it’s function?

Answer 18

purkinje cells; it is the output layer

Question 19

What does damage to the cerebellum result in?

Answer 19

doesn’t abolish movement but disrupts it’s timing and execution

Question 20

What is the cerebellum’s main process of integrating information?

Answer 20

comparing information about the intended vs actual movements and deciding what to do next

Question 21

What is glabrous skin?

Answer 21

skin without hair follicles but with more sensory receptors

Question 22

What are the 3 types of somatosensory receptors?

Answer 22

1) Nociceptors
2) Hapsis
3) Proprioreceptors

Question 23

What are some qualities of nociceptors? What kinds of cells are they?

Answer 23

they are involved in irritation and the perception of pain, temperature and itch; free nerve cells

Question 24

What are some qualities of hapsis receptors? What kind of cells are they?

Answer 24

They respond to pressure and touch and allow us to discriminate objects; a dendrite attached to hair, connective tissue or encased in connective tissue

Question 25

What are some qualities of proprioceptors? What kind of cells are they?

Answer 25

involved in the perception of movement and body, limb and head position; encapsulated nerves sensitive to stretch

Question 26

What are the 4 main types of Hapsis receptors?

Answer 26

1) Pacinian 2) Merkel 3) Ruffini 4) Meissner's

Question 27

What is a pacinian corpuscle responsible for? Is it rapid or slow?

Answer 27

flutter movements; rapid

Question 28

What is a Meissner's corpuscle responsible for? Is it rapid or slow?

Answer 28

touch; rapid

Question 29

What is a Ruffini corpuscle responsible for? Rapid or slow?

Answer 29

indentation; slow

Question 30

What is Merkel's receptor for? Rapid or slow?

Answer 30

stead skin indentation; slow

Question 31

Are proprioceptors all rapid or slow?

Answer 31

rapid

Question 32

Are nociceptors rapid or slow?

Answer 32

slow

Question 33

What are posterior root ganglion neurons?

Answer 33

Single long dendrites just outside the SC that carry somatosensory information to the CNS

Question 34

What are the 2 types of posterior root ganglion neurons and how do they differ?

Answer 34

1) Proprio & haptic; large and myelinated | 2) Nociceptive; small and nonmyelinated

Question 35

What type of cells are in the posterior spinothalamic tract? Where do they cross over?

Answer 35

Haptic and proprio; in the posterior column nuclei in the brain

Question 36

What type of cells are in the anterior spinothalamic tract? Where do they synapse and cross over?

Answer 36

nociceptors; on anterior grey matter; cross over right away

Question 37

Where do both spinothalamic tracts end up synapsing on in the brain?

Answer 37

the ventrolateral thalamus

Question 38

What areas other than nociceptors are involved in pain perception? What do they do?

Answer 38

Haptic: ID location and identity Midbrain: arousal Amygdala: emotional response Hypothalamus: hormonal and cardio vascular

Question 39

What is the gate theory of pain?

Answer 39

haptic-proprio can reduce pain perception whereas absence can increase pain perception

Question 40

How is the PAG involved in pain perception? What can be done with it to reduce pain?

Answer 40

in the midbrain and is related to opioids; stimulating it reduces pain perception

Question 41

What is another name for organ pain? why?

Answer 41

referred pain; because you feel it elsewhere

Question 42

What is involved in the vestibular system? What is a disease that can result in vertigo in this system?

Answer 42

the semicircular canals detect 3d location and ID; cilia fire to one direction and inhibited to other; Miniere disease

Question 43

Where does the primiary somatosensory cortex receive projects from? What Brodmann's areas is it? What are it's main functions?

Answer 43

the thalamus; 3-1-2; construct perceptions from somatosensory information

Question 44

What Brodmann's areas is S2? What does it do? Where is it?

Answer 44

5 and 7; in parietal behind S1; refines perceptual construtions and sends info to frontal cortex

Question 45

What are the 4 different somatosensory homunculi?

Answer 45

1) rapid adapting skin receptors 2) deep tissue pressure and joint receptors 3a) muscle receptors 3b) slow respond skin receptors

Question 46

What do somatosensory homunculi areas of 3a and 3b do?

Answer 46

respond to specific activity of certain body parts; integrate it and send it to area 1

Question 47

What is apraxia? What is damaged a lot of the time that it results?

Answer 47

inability to make voluntary movements; especially to make proper use of an object; S2

Question 48

What is astereognosia?

Answer 48

inability to recognize objects by touch

Question 49

What is asomotagnosia?

Answer 49

inability to recognize body parts

Question 50

What two more parts are involved in pain perception?

Answer 50

the anterior cingulate cortex; emotional | Raphe nucleus; can monitor and block pain

Question 51

What is unique about ballistic movements?

Answer 51

they require no sensory feedback

Question 52

What does the posterior parietal association cortex do?

Answer 52

it integrates information on body position, external objects; it receives information from all senses

Question 53

What does the dorsolateral prefrontal association cortex do?

Answer 53

it evaluates external stimuli and initiates reactions to them; it is the first to fire in anticipation of motor responses

Question 54

Where does stimulation of the primary motors cortex produce movement?

Answer 54

the opposite side of the body

Question 55

What do the 2 dorsolateral and ventromedial tracts have in common? How do they differ?

Answer 55

Both: project from M1 and mediate voluntary movement Ventro: more diffuse and send information to proximal muscles Dorso: project to distal muscles

Question 56

What is isomeric muscle contraction?

Answer 56

joint position and muscle length do not change; do not pull bones in

Question 57

What is Dynamic muscle contraction?

Answer 57

muscle length and joint position change; bones are pulled in

Question 58

What reflex is monosynaptic? What isnt?

Answer 58

``` stretch reflex (petallar) withdrawal (nociceptors) ```