Lecture 50 - Motor Control 1 & 2

Question 1

what is the hierarchy in motor control

Answer 1

1. cerebral cortex
2. subcortical nuclei
3. brainstem nuclei and cerebellum
4. spinal cord

Question 2

describe the motor neurons in the spinal cord

Answer 2

ventral horn (grey matter)
sensory
cholinergic

Question 3

summarize the patellar reflex in 5 steps

Answer 3

1. tendon tap
2. activation of muscle spindles via stretching
3. action potential generated
4. synapse in the spinal cord - spindle fibers to motor neurons
5. motor neuron activation

Question 4

T/F: most reflexes are monosynaptic

Answer 4

FALSE - involve one or more interneurons

Question 5

The “withdrawal” reflex utilizes what general circuitry

Answer 5

flexor and cross-extensor reflex arc

Question 6

what is the righting reflex

Answer 6

animal is flipped onto its back or side, the sensory input from the vestibular system and proprioception triggers motor responses

Question 7

T/F: the righting reflex is dependent on gravity

Answer 7

TRUE

Question 8

vestibular nuclei are involved in

Answer 8

modulation of tone in extensor muscles (upright posture)

Question 9

red nuclei are involved in

Answer 9

unconscious stereotyped movements (gait)

Question 10

what is in charge if high-order control of gait and control of distal muscles for complex movement

Answer 10

red nucleus

Question 11

damage to the cerebellum results in what

Answer 11

ataxia

Question 12

what is the cerebellum in charge of

Answer 12

coordinating motor function and executing rapid movements

Question 13

T/F: cerebellum receives output from the motor cortex and provides “error” correction signals

Answer 13

TRUE

Question 14

the Purkinje fibers do what

Answer 14

inhibits unwanted movement

Question 15

the basal nuclei includes what structures

Answer 15

striatum
globus pallidus external
globus pallidus internal

Question 16

what does the basal nuclei project to

Answer 16

the thalamus and subthalamic nuclei

Question 17

what does the basal nuclei receive input from

Answer 17

all cortical areas and the substantial nigra

Question 18

what input is associated with the substantial nigra

Answer 18

dopamine

Question 19

summarize the direct pathway in 4 steps

Answer 19

1. input from the motor cortex
2. synapse GPe to GPi (inhibitory to inhibitory
3. sensory input to the motor thalamus
4. control unwanted movement

Question 20

is the substantial nigra excitatory of inhibitory in the direct pathway

Answer 20

excitatory

Question 21

what is the end goal of the indirect pathway

Answer 21

stop movement

Question 22

D1 receptors in the ___ pathway facilitate ____

Answer 22

direct; excitation

Question 23

D2 receptors in the ___ pathway facilitate ____

Answer 23

indirect; inhibition

Question 24

hypokinesia

Answer 24

inability to initiate movement (Parkinson’s)

Question 25

hyperkinesia

Answer 25

excessive motor activity (Huntington’s)

Question 26

what are the functions of the motor cortex

Answer 26

1. voluntary control
2. proportionately large area devoted to areas of the body w capacity for controlled movements
3. corticospinal (pyramidal) tracts
4. learned, skilled, fine, voluntary control of muscles