top down movement control

Question 1

What are innate human motor

responses?

Answer 1

Sensory abilities

• Motor abilities
– Postural reflex
– Grasping reflex

Question 2

Sudden stretch of a
muscle leads to Muscle
Spindle Discharge of 1a
afferent neurons…

Alpha motor Neurons
respond with contraction

what is this called

Answer 2

Monosynaptic Myotatic Stretch Reflex

Question 3

what mediates the Contraction and

Inhibition of Flexors vs. Extensors (and vice versa)

Answer 3

Spinal Interneurons

Question 4

what is the basis for centeral pattern generators

Answer 4

Spinal Interneurons mediating the contralateral

Extension of limbs

Question 5

the CPG is wired to..

Answer 5

activate muscles in

coordinated oscillations

Question 6

motor system

Answer 6

consist of all our muscles and the neurons that control them

Question 7

motor control can be divided into two parts

Answer 7

spinal chords commans of control and coordinatwed muscle

brains control

Question 8

two categories of muscle

Answer 8

striated and smooth

Question 9

smooth muscle

Answer 9

lines arteries, digestive tract.

innervated by nerve fibers from autonomic nervous system

Question 10

two types of striated muscle

Answer 10

cardiac

skeletal

Question 11

skeletal muscle controls..

Answer 11

functions to move bones around joints
facial expressions

inhale and exhale

Question 12

muscle fibers

Answer 12

cells of skeletal muscle

Question 13

each muscle fiber is innervated with..

Answer 13

a single axon branch from the centeral nervous system

Question 14

skeletal muscles are part of what

Answer 14

somatic nervous system

they are under voluntary control and it generates behavior

Question 15

flexation

Answer 15

movement in direction that closes the joint

Question 16

extension

Answer 16

movement that opens joint

Question 17

what are antagonist of the extendors

Answer 17

flexors

Question 18

when muscles work together, they are called…

Answer 18

synergist

Question 19

why are flexors and extendors antagonistic to each other

Answer 19

they pull in opposite directions of each other

Question 20

lower motor neurons

Answer 20

provide input to the spinal cord

Question 21

two main categories of lower motor neurons

Answer 21

alpha motor neuron

gamma motor neuron

Question 22

alpha motor neuron

Answer 22

directly triggers the generation of force by muscles

Question 23

what controls proprioceptive feedback

Answer 23

muscle spindles

Question 24

Proprioceptive Feedback

Answer 24

refers to the sense of limb position and movement

critical for proper balance and motor control

means to keep track of and control the different parts of the body

Question 25

how does an alpha motor neuron communicate with a muscle fiber

Answer 25

releasing ACh at a muscle at the neuromuscular junction

Question 26

how does the CNS grade muscle contraction

Answer 26

through the rate of firing. a sustained contraction requires continuous action potentials

Question 27

lower motor neurons are controlled by..

Answer 27

synaptic inputs in the ventral horn

Question 28

slow fibers (s-fibers)

Answer 28

realitively slow to contract but ca sustain contraction for a long time without fatigue contains red fibers

Question 29

fast muscle fibers

Answer 29

contract rapidly and powerfully. contain fewer mitochondria and rely mostly on anaerobic metabolism contains white fibers

Question 30

muscles are determined by..

Answer 30

the type of innervation it gets. if it recieves a synaptic contact from a fast motor neuron, it becomes a fast fiber and vice versa

Question 31

john eccles experiment

Answer 31

normal innervation of a fast muscle was removed and replaced with a nerve that normally innevated a slow muscle it resulted in the muscle aquiring slow properties this change in phenotype can be induced simply by changing the activity in the motor neuron from a fast pattern to a slow pattern this experiment raised questions about about neurons switching phenotype as a consequence of synaptic activity and may be a basis for learning and memory

Question 32

means to keep track of and control the different parts of the body

Answer 32

Pro receptive feedback

Question 33

Where does rubrospinal tract originate

Answer 33

Red nucleus of the midbrain

Question 34

Humans vs other mammals lateral pathway

Answer 34

We mostly use corticospinal tract while other animals use rubospinal

Question 35

Pathway for balance, body position and visual environment

Answer 35

Ventromedial pathway

Question 36

Ventromedial pathway (new)

Answer 36

Uses sensory info Info for balance, body position, and visual environment ENSURES THAT OUT IMAGE OF THE WORLD REMAINS STABLE Keeps head balanced on shoulders as body moves through space Turns head to stimuli

Question 37

Tectospinal tract (new)

Answer 37

Helps orient head trunk and shoulders by communicating with superior colliculus visual information

Question 38

Area 4 and 6

Answer 38

Motor cortex

Question 39

How was primary motor cortex (m1) found

Answer 39

Penfeild electrically stimulates this area in people with epilepsy while giving surgery He noticed that weak stimulation in area 4 in precentral gurus would elicit a twitch of muscles in different regions of body on countralateral side

Question 40

PMA

Answer 40

Promoter area

Question 41

SMA

Answer 41

Suplimental motor area

Question 42

Where is somatopic motor map located

Answer 42

Area 6 (PMA) and (SMA)

Question 43

SMA sends axons to...

Answer 43

Motor units directly

Question 44

Individual neurons in motor cortex and direction

Answer 44

Individual neurons control direction

Question 45

How is direction of movement determined

Answer 45

Much of motor cortex is active for every movement Each cell represents a vote for which direction movement Direction of movement is made by averaging votes registered by each cell

Question 46

Rat experiment with plasticity

Answer 46

They cut motor nerve that supplies muscle of snout and whiskers, and eyes Regions of M1 that evoked whisker movements now would elicit forelimb or eye movements This concludes that motor map can be reorganized and other types of cortical reorganization can provide a basis for learning fine motor skills