The Motor System

Question 1

What are the 5 facets of hierarchical movement control?

Answer 1

Decision, sequencing, production, timing and error

Question 2

What are the major components of the motor system?

Answer 2

Forebrain, brainstem and spinal cord

Question 3

What is the role of the forebrain in the motor system?

Answer 3

Complex voluntary movements

Question 4

What is the role of the brainstem in the motor system?

Answer 4

Timing and control

Question 5

What is the role of the spinal cord in the motor system?

Answer 5

Reflexes, somatosensory direction of movement

Question 6

What is the role of the basal ganglia in hierarchical movement control?

Answer 6

Production of appropriate movement force

Question 7

What is the role of the cerebellum in hierarchical movement control?

Answer 7

Timing and accuracy

Question 8

How does the forebrain organize movement?

Answer 8

Motor sequences

Question 9

What are motor sequences?

Answer 9

Movement sets produced as a unit by the brain

Question 10

What brain region is responsible for planning and initiating motor sequences?

Answer 10

Frontal lobes

Question 11

What are the 3 motor regions of the frontal lobe?

Answer 11

Prefrontal cortex
Premotor cortex
Primary motor cortex

Question 12

What is the role of the prefrontal cortex in movement?

Answer 12

Planning movements

Question 13

What is the role of the premotor cortex in movement?

Answer 13

Sequencing and organizing movements

Question 14

What is the role of the primary motor cortex in movement?

Answer 14

Producing specific movements

Question 15

The PFC does not specify the precise movements to make, what does it do?

Answer 15

Decides the goal of the movement (planning)

Question 16

How would damage to the prefrontal cortex show in motor systems?

Answer 16

Unable to plan how to direct the goal of the movement– eg. how can i reach this water bottle?

Question 17

What would damage to the premotor cortex look like?

Answer 17

Motor sequences could not be accomplished (think monkeys who cannot complete motor sequences to get food)

Question 18

What evidence is suggestive of a movement hierarchy in the Frontal Lobe regions?

Answer 18

Directionality of blood flow

Question 19

What is the role of the brainstem in controlling motor behaviour of species?

Answer 19

Responsible for species-typical behaviours

Question 20

What are species-typical behaviours

Answer 20

Innate actions produced by every member of a species (eg. hissing in felines)

Question 21

Grooming behaviours are controlled by what region of the brain?

Answer 21

Brainstem

Question 22

Damage to the brainstem results in difficulties with what type of movement?

Answer 22

Voluntary

Question 23

What is locked-in syndrome? What region of the brain causes locked-in syndrome?

Answer 23

Condition where patient is aware and awake but all voluntary muscled are paralyzed other than the oculomotor cranial nerves of the eyes (vertical movement)

Question 24

What is cerebral palsy?

Answer 24

Condition where voluntary movements are difficult, atonia and poor posture– caused by brainstem trauma before or after birth

Question 25

What is quadripalegia?

Answer 25

Paralysis and loss of sensation in both the legs and arms (C1-T1)

Question 26

What is parapalegia?

Answer 26

Paralysis and loss of sensation confined to lower body and legs (after T1)

Question 27

What is the homunculus (body map)?

Answer 27

Representation of the human body in motor cortex; bilateral, contralateral control

Question 28

What region of the motor cortex controls lower limbs?

Answer 28

Dorsal

Question 29

What region of the motor cortex (M1) controls upper body, hands and face?

Answer 29

Ventral

Question 30

The motor cortex represents not specific muscles, but rather what?

Answer 30

A grouping of movement categories.

Question 31

True or false: M1 neurons are activated not just while performing a particular movement but also when imagining those movements as well

Answer 31

True

Question 32

What are corticospinal tracts/pyramidal tracts?

Answer 32

Efferent pathways from the motor cortex to the brainstem and then to the spinal cord to produce movements

Question 33

Why are there two corticospinal tracts, one crossed (lateral) and one uncrossed (anterior)?

Answer 33

Axons descend from the motor cortex into the brainstem, then half cross over to the opposite side of the brainstem.

Question 34

What is the role of the crossed/lateral corticospinal tract?

Answer 34

Moving limbs on **opposite side**

Question 35

What is the role of the uncrossed/anterior corticospinal tract?

Answer 35

Moving muscles at the midline of the body on the **same side**

Question 36

What are lateral neurons in the spine?

Answer 36

Neurons that project to limbs to produce movement

Question 37

What are medial neurons?

Answer 37

Neurons that control the body's trunk

Question 38

How do motor neurons produce body movement?

Answer 38

These motor neurons will eventually synapse with the muscles that ultimately produce the body movement

Question 39

What are the 3 motor nuclei of the basal ganglia?

Answer 39

Caudate nucleus and putamen (striatum) Subthalamic nucleus Globus pallidus

Question 40

Where does the basal ganglia receive input from?

Answer 40

Cerebral cortex (motor cortex) and dopaminergic system (substantia nigra)

Question 41

What is the role of the basal ganglia in the force of movement?

Answer 41

Control and coordination

Question 42

What damaged region to the basal ganglia causes hyperkinetic movements and dyskinesias?

Answer 42

Striatum (Caudate and putamen)

Question 43

What damaged region to the basal ganglia causes hypokinetic movements?

Answer 43

Substantia nigra

Question 44

What is the associative cause of parkinson's disease?

Answer 44

Associated with dopamine depletion in the basal ganglia and its connections with the substantia nigra

Question 45

What is parkinsonism?

Answer 45

an umbrella term referring to the common motor disorder symptoms, which may occur in conditions outside of just PD

Question 46

What is true about disposition to Parkinson's?

Answer 46

Can be idiopathic or non-idiopathic

Question 47

What is an effective treatment for early PD symptoms?

Answer 47

Deep brain stimulation of the substantia nigra and other areas of the basal ganglia

Question 48

What is Huntington's disease (Huntington's chorea)?

Answer 48

A genetic condition in which there is a build of the huntingtin protein which causes neurodegeneration of the basal ganglia

Question 49

What is true about the development of Huntington's disease?

Answer 49

It is autosomnal dominant-- If you have the allele you will develop the disease. Onset is around 30-40yrs

Question 50

What is the time course of HD?

Answer 50

Progressive 10-15 years

Question 51

What are symptoms of HD?

Answer 51

Triad of symptoms: A progressive motor disturbance Cognitive impairment Psychiatric symptoms (anxiety, depression, late-stage psychosis)

Question 52

What is dysarthria?

Answer 52

A motor speech disorder; characterized by difficulties controlling the tongue and speech muscles/structures

Question 53

What is dysphagia?

Answer 53

Difficulties with swallowing; leads to difficulty with eating

Question 54

What happens when we practice or neglect to practice a motor skill?

Answer 54

We lose or gain the skills -- cerebellum does this work

Question 55

What is the anatomy of the cerebellum?

Answer 55

Flocculus and two hemispheres (lateral and medial)

Question 56

What is the Flocculus (floccular lobe)?

Answer 56

Small but dense lobe; projects from the ventral surface Involved in eye movements and balance (input from the vestibular system)

Question 57

What are the hemispheric roles of the cerebellum?

Answer 57

Lateral parts Controls movement of limbs, hands, feet, and digits Medial parts Controls movement of face and midline of body

Question 58

How does the Cerebellum improve movement control?

Answer 58

Timing Maintaining movement accuracy (correction of errors)

Question 59

How does the cerebellum correct movement errors?

Answer 59

Involved with balance and orientation