20,21-Motor1,2

Question 1

Voluntary motor control requires at least 3 operations:

Answer 1

1. Select action (decision)
2. Compute desired trajectory (sensorimotor coordinate transformation)
3. Compute muscle forces/joint torques requires to achieve desired trajectory

Question 2

Dynamics

Answer 2

muscle forces

Question 3

Kinematics

Answer 3

desired trajectory

Question 4

Sensorimotor transformation

Answer 4

convert spatial information from sensory to motor coordinates

Question 5

Motor planning

Answer 5

compute desired trajectory (kinematics)

Question 6

Inverse dynamics problem

Answer 6

given desired trajectory, compute muscle forces and joint torques (dynamics) necessary to achieve trajectory

Answer 7

true

Question 8

Bell-shaped velocity profile is controlled by

Answer 8

central pattern generators, not brain

Question 9

CPGs

Answer 9

central pattern generators

Question 10

Component of the motor system that acts as a ‘trainable gate’

Answer 10

basal ganglia

Question 11

Component of the motor system that supplies voluntary motor commands

Answer 11

cerebral cortex (primary motor, premotor, supplementary motor)

Question 12

M1 neurons principally use [kinematic/dynamic] encodings

Answer 12

kinematic, but not purely

Question 13

Corticospinal neurons terminate / originate in the brain at (x5)

Answer 13

• motor
• premotor
• cingulate
• supplementary motor
• somatosensory

Question 14

Corticospinal neurons originate / terminate in the spinal cord at (x2)

Answer 14

• ventral horn (motor cortical areas)
• dorsal horn (somatosensory areas)

Question 15

Each muscle fiber is innervated by ___ motor neuron(s)

Answer 15

one

Question 16

Each motor neuron innervates ___ muscle fiber(s)

Answer 16

10-1000

Question 17

Motor unit

Answer 17

muscle fibers innervated by one motor neuron

Question 18

GTO

Answer 18

golgi tendon organ

Question 19

GTOs sense ___

Answer 19

muscle force / tension

Question 20

GTOs are connected to what fiber type

Answer 20

Ib

Question 21

Muscle spindles sense ___

Answer 21

muscle length

Question 22

Muscle spindles send afferent information via ___ fibers

Answer 22

Ia

Question 23

Muscle spindles are stimulated by ___

Answer 23

gamma motor neurons

Question 24

Types of gamma motor neurons and muscle spindle (x2)

Answer 24

• dynamic
• static

Question 25

During voluntary muscle shortening, Ia activity [incr/decr]

Answer 25

increases (presumably because of prior increase in gamma activity for new set point?)

Question 26

Locomotor CPG is located in ___

Answer 26

spinal cord

Question 27

MLR

Answer 27

mesencephalic locomotor region (in pons)

Question 28

Stimulation of MLR triggers ___, with ___ controlled by stimulation intensity

Answer 28

stepping, pace

Question 29

[True/false] Same CPG can produce different motor programs depending on strength of input

Answer 29

true

Question 30

Large amplitude movements have [more/less] noise

Answer 30

more

Question 31

Average sensory latency

Answer 31

100 ms

Question 32

Obstacles to effective motor control (x6)

Answer 32

- redundancy - noise - delays - uncertainty - non-stationarity - nonlinearity

Question 33

[True/false]: Frame of reference is task-independent

Answer 33

false

Question 34

kinematics

Answer 34

position / velocity / acceleration

Question 35

kinetics

Answer 35

forces and derivatives

Question 36

inverse model is for ___, while forward model is for ___

Answer 36

control, prediction

Question 37

[True/false]: There is substantial evidence for inverse models

Answer 37

true

Question 38

[True/false]: There is substantial evidence for efference copy

Answer 38

false

Question 39

[True/false]: There is substantial evidence for forward models

Answer 39

false (soft evidence only)

Question 40

[True/false]: Brain chooses egocentric reference frame that minimizes movement error

Answer 40

true

Question 41

2/3 power law relates ___ to ___

Answer 41

path curvature, angular velocity

Question 42

Motor equivalence

Answer 42

suggests that movoments are represented abstractly in the brain

Question 43

internal model

Answer 43

relates information about muscle lengths and joint angles to the position of the hand in space (eg)

Question 44

[True/false]: Most motor learning is implicit/procedure

Answer 44

true