Chapter 14: Brain Control of Movement

Question 1

The( ) influences motor activity of the spinal cord -> Initiates voluntary movements

Answer 1

brain

Question 2

Hierarchy of controls
Highest level: strategy (1) -> deciding what to do; deals with complex information to decide the course of action
Middle level: tactics (2) -> which muscles to use, how much force to use; how to move the muscles of the body to achieve the course of action
Lowest level: execution (3)

Answer 2

1. Association area of neocortex, basal ganglia
2. Motor cortex, cerebellum
3. Brain stem, spinal cord

Question 3

(): Sensory information used by all levels of the motor system

Answer 3

sensorimotor system

Question 4

Axons from brain descend along two major pathways:

Answer 4

Lateral pathways
Ventromedial pathways

Question 5

axon pathway from brain that mediates Voluntary movement— originates in cortex

Answer 5

lateral pathways

Question 6

components of lateral pathways

Answer 6

1. corticospinal (pyramidal) tract
2. rubrospinal tract

Question 7

lateral pathway component: Motor cortex neurons directly innervate spinal cord; originates directly from motor cortex

Answer 7

corticospinal stract (direct)

Question 8

the corticospinal tract passes through (lateral/medial) side of midbrain and (2), where the decussation occurs

Answer 8

1. lateral
2. medulla

Question 9

lateral pathway component: indirectly control spinal cord neurons; suggested purpose: controls fine fractionated movements of arms and hands (not present in monkeys)

Answer 9

rubrospinal tract

Question 10

the rubrospinal tract originates from () in the midbrain, which are governed by neurons in the motor cortex

Answer 10

red nucleus neurons

Question 11

The effects of experimental corticospinal lesions

Answer 11

Deficit in fractionated movement of arms and hands

Question 12

Both lateral pathways can (1) for the other if the other has a lesion -> allows for recovery after some time; subsequent (2) in the other pathway reverses recovery

Answer 12

1. compensate
2. lesion

Question 13

() in human can affect (cause lesions) in motor cortex or corticospinal tract -> causes paralysis on contralateral side, with possibility of recovery over time

Answer 13

strokes

Question 14

() pathways mediate balance and posture; originate in the brain stem

Answer 14

ventromedial

Question 15

4 components of ventromedial pathways

Answer 15

1. vestibulospinal tracts
2. tectospinal tract
   3-4. pontine/medullary reticulospinal tract

Question 16

ventromedial pathway component: manages muscles to maintain head balance and head turning

Answer 16

vestibulospinal tracts

Question 17

ventromedial pathway component: manages muscles for the orienting response -> Turning your head and moving your eye when you focus on an object

Answer 17

tectospinal tract

Question 18

vestibulospinal tracts originate from (), which is the projection site of info from vestibular organs in inner ear -> combines sensory (proprioception) and motor info

Answer 18

vestibular nucleus

Question 19

the vestibular spinal tracts pass near the (ventral/dorsal) side of the spinal cord

Answer 19

ventral

Question 20

the tectospinal tract originates from the (1) and receives info from the (2) -> processing center for visual info and motor execution

Answer 20

1. superior colliculus (optic tectum)
2. retina

Question 21

reticulospinal tract: enhances antigravity reflexes -> muscles resist effect of gravity to maintain standing position

Answer 21

pontine reticulospinal tract

Question 22

reticulospinal tract: liberates and relaxes antigravity muscles from reflex control

Answer 22

medullary reticulospinal tract

Question 23

motor cortex comprises areas () of the frontal lobe

Answer 23

4 and 6

Question 24

area 4 of motor cortex: ()

Answer 24

primary motor cortex, M1

Question 25

(): “higher” motor area (Penfield)

Answer 25

Area 6

Question 26

area 6 consists of ()

Answer 26

Lateral region -> premotor area (PMA) Medial region -> supplementary motor area (SMA)

Question 27

Body areas that require more sensitive motor movements correspond to (narrower/wider) areas in motor cortex

Answer 27

wider

Question 28

the posterior parietal cortex consists of areas () of the frontal cortex

Answer 28

5 and 7

Question 29

- Area (): inputs from areas 3, 1, and 2 (S1) (from somatosensory cortex and combines info for deciding output)

Answer 29

5

Question 30

Area (): inputs from higher-order visual cortical areas such as MT

Answer 30

7

Question 31

Represent highest levels of motor control -> Decisions made about actions and their outcome

Answer 31

posterior parietal cortex

Question 32

Contributions of Posterior Parietal and Prefrontal Cortex: () -> abstract thought, decision making, and anticipating consequences of action

Answer 32

Anterior frontal lobes

Question 33

(): Actions converted into signals specifying how actions will be performed. (PMA neurons vs SMA neurons)

Answer 33

Area 6

Question 34

() neurons were shown by Evarts to be active during the planning of a muscle movement ("Ready")

Answer 34

PMA

Question 35

some neurons in cortical area 6 respond when movement is only imagined -> May be part of extensive brain system for understanding actions and intentions of others

Answer 35

mirror neurons

Question 36

(): Selection and initiation of willed movements; Important source of inputs towards area 6 and motor cortex

Answer 36

basal ganglia

Question 37

the basal ganglia consists of: ()

Answer 37

striatum (caudate nucleus + putamen), globus pallidus, subthalamic nucleus

Question 38

midbrain structure that is reciprocally connected with the basal ganglia; important for stimulating striatum thru dopaminergic innervation

Answer 38

substantia nigra

Question 39

most of the inputs from basal ganglia pass through the () of the thalamus

Answer 39

ventral lateral (VL) nucleus

Question 40

target of the cortical input to the basal ganglia

Answer 40

striatum

Question 41

2 major points of the motor loop

Answer 41

basal ganglia, cortex

Question 42

the basal ganglia provides major input to area ()

Answer 42

6

Question 43

Excitatory connection from cortex to putamen (basal ganglia striatum neurons)

Answer 43

direct motor loop

Question 44

cortical activation of the direct motor loop:

Answer 44

excites putamen, inhibits globus pallidus (GPI), and releases VLo from inhibition

Question 45

activity in VLo boosts activity in ()

Answer 45

SMA neurons

Question 46

(): trouble initiating willed movements due to increased inhibition of the thalamus by basal ganglia

Answer 46

Parkinson’s disease

Question 47

Organic basis of Parkinson's : degeneration of () -> (lack of stimulation via dopamine)

Answer 47

dopaminergic substantia nigra inputs to striatum

Question 48

(): facilitates production of dopamine to alleviate some Parkinson's symptoms

Answer 48

l-dopa treatment

Question 49

Loss of neurons in caudate nucleus, putamen, globus pallidus; Consequent loss of inhibitory output to the thalamus -> motor systems can’t be suppressed properly (overactivation of motor loop)

Answer 49

Huntington's Disease

Question 50

in Huntington's disease, () is primarily responsible for dementia and personality changes

Answer 50

cortical degeneration

Question 51

Electrical stimulation of () causes contraction of small group of muscles.

Answer 51

area 4

Question 52

(): pyramidal cells in cortical layer 5

Answer 52

Betz cells

Question 53

Two sources of input to Betz cells

Answer 53

Cortical areas Thalamus

Question 54

Extensor motor neurons are innervated by ()

Answer 54

Betz cells (excitatory)

Question 55

Flexor motor neurons are connected to ()

Answer 55

inhibitory interneurons

Question 56

Movement of direction encoded by () of neurons

Answer 56

collective (populational) activity

Question 57

direction of movement is determined by () - a tally (and averaging) of votes; activity of each cell represents a single “vote”.

Answer 57

population vectors

Question 58

Motor map is easily changed -> adapts to changes such as ()

Answer 58

loss of connection to certain muscles

Question 59

function of cerebellum

Answer 59

mediates sequence of muscle contractions

Question 60

(): uncoordinated and inaccurate movements; caused by cerebellar lesion

Answer 60

Ataxia

Question 61

(): decomposition of synergistic multi-joint movements (e.g. catching a ball); caused by cerebellar lesion

Answer 61

Dyssynergia

Question 62

(): overshoot or undershoot target; caused by cerebellar lesion

Answer 62

Dysmetria

Question 63

() – increases surface area in cerebellum (similar to gyri and sulci)

Answer 63

Folia and lobules

Question 64

Relay cerebellar cortical output to brain stem structures

Answer 64

deep cerebellar nuclei

Question 65

(): axial musculature; connection between left and right cerebellar hemispheres; contributes to ventromedial pathways

Answer 65

Vermis

Question 66

cerebellar hemispheres mediate ()

Answer 66

limb movements

Question 67

Most abundant cells in cerebellum Very densely packed (blue) Located in inner side of cerebellum Excitatory neurons

Answer 67

granule cells

Question 68

granule cells have () that are projected in molecular (outer) layer -> connects Purkinje cells

Answer 68

parallel fibers

Question 69

Very large cells (one of the largest cells in CNS) Many dendrites and processes Packed in outer molecular layer of cerebellum Collect info from granule cells via the granule cell parallel fibers Inhibitory neurons -> project inhibitory axons towards deep cerebellar nuclei

Answer 69

Purkinje cells

Question 70

Cerebellum is the center for the proper execution of ()

Answer 70

planned, voluntary, multijoint movements

Question 71

Axons from layer V pyramidal cells in the sensorimotor cortex form massive projections to pons.

Answer 71

Pontine nuclei

Question 72

the corticopontocerebellar tract 20 times larger than the () tract;

Answer 72

pyramidal