Posture and Movement

Question 1

Posture/Movement hierarchy

Answer 1

motor nuclei - hindbrain - midbrain - forebrain

Question 2

Where is the reticular formation found?

Answer 2

Throughout the midbrain and hindbrain

Question 3

Functions of the reticular formation

Answer 3

• ascending system to alert cerebral cortex vs. coma
• vegetative centers: regulate heart rate, respiration, digestive tract, micturition, etc.
• standing posture and muscle tone

Question 4

What is the pontine reticulospinal tract (of the reticular formation)?

Answer 4

• arises from neurons located laterally in pons and medulla
• dominant and spontaneously active
• activates extensor muscle of proximal joints

Question 5

What is the medullary reticulospinal tract (of the reticular formation)?

Answer 5

• arises from neurons located medially in medulla
• inhibits neurons to extensor muscles
• excites neurons to flexor muscles
• not spontaneously active, driven by cerebral cortex to preset movement posture

Question 6

What are the two tracts of the vestibular nuclei?

Answer 6

lateral vestibulospinal tract (drives standing posture)

medial vestibulospinal tract (controls neck muscles)

Question 7

What does the red nucleus give rise to?

Answer 7

Rubrospinal tract

Question 8

Rubrospinal tract

Answer 8

principal descending tract for voluntary movement in domestic animals

Question 9

What is the tectum?

Answer 9

roof of the midbrain

Question 10

What is the tectum made of?

Answer 10

Rostral and caudal colliculi

Question 11

Functions of rostral and caudal colliculi

Answer 11

orient head, eyes, and ears towards sudden visual and auditory stimuli, respectively

Question 12

Rostral colliculus gives rise to what 2 tracts?

Answer 12

tectospinal fibers (head turning)
tectobulbar fibers (ear and eye movement)

Question 13

Where is the subthalamus found?

Answer 13

forebrain

Question 14

Function of the subthalamus

Answer 14

regulates voluntary movement (damage results in hyperkinetic movements)

Question 15

Where are the basal nuclei found?

Answer 15

telencephalon

Question 16

Name the 5 basal nuclei that participate in circuits that involve the thalamus and cerebral cortex

Answer 16

accumbens
caudate
putamen
globus pallidus
endopeduncular

Question 17

Functions of the basal nuclei

Answer 17

• suppress unwanted movements

- regulate the selection, onset, and cessation of voluntary movement

Question 18

Function of the caudate nucleus

Answer 18

selecting and assembling movements, particularly during learning

Question 19

Function of putamen nucleus

Answer 19

controls amplitude and durations of movements, particularly in the case of habitually performed movements

Question 20

All projections from basal nuclei are inhibitory or excitatory?

Answer 20

inhibitory

Question 21

What are the 2 output basal nuclei?

Answer 21

globus pallidus and endopeduncular nucleus (they suppress movement)

Question 22

What are the 3 input basal nuclei?

Answer 22

accumbens
caudate
putamen

Question 23

How does the striatum control spontaneously active output nuclei? (2 pathways)

Answer 23

direct pathway (facilitates desired movement)
indirect pathway (suppresses unwanted movement)

Question 24

Look at Movement-Related Basal Nuclei Circuits

Answer 24

Look at Movement-Related Basal Nuclei Circuits

Question 25

Characteristics of motor area of the cerebral cortex

Answer 25

• located around cruciate sulcus
• main source of two descending pathway systems
• organized to control movements, not muscles

Question 26

Characteristics of premotor area of the cerebral cortex

Answer 26

• projects to the motor area

- involved in assembling complex movements and generating learned, rapid-sequence movements

Question 27

Characteristics of supplementary motor area of the cerebral cortex

Answer 27

-active when thinking about proposed movements

Question 28

Where do voluntary movements originate?

Answer 28

forebrain from circuits involving basal nuclei, thalamus, and motor areas of the cerebral cortex

Question 29

Voluntary movement process

Answer 29

external cue/internal urge - decision - selection - execution

Question 30

What are the 2 categories for voluntary movement?

Answer 30

pyramidal tract

extrapyramidal tract

Question 31

Characteristics of pyramidal tracts

Answer 31

• connect to motor unit efferent neurons
• axons travel in pyramids of medulla
• controls precise movement

Question 32

Characteristics of extrapyramidal tracts

Answer 32

-control trunk and proximal limb musculature

principal tracts are rubrospinal, pontine reticulospinal, and medullary reticulospinal

Question 33

Look at Movement Initiation Schema

Answer 33

Look at Movement Initiation Schema