Motor systems

Question 1

Movement starts with an internal representation (the goal of the intended movement)

Answer 1

And translates it into the appropriate into the appropriate motor commands to achieve the goal

Question 2

Motor system has hierarchical and parallel organization

Answer 2

Motor cortex -> brainstem -> spinal cord

Question 3

What works in parallel w motor cortex and brainstem?

Answer 3

Basal ganglia and cerebellum

Question 4

The abstract aspects of action are

Answer 4

ROSTRAL

Question 5

Specific action required to achieve abstract goal are

Answer 5

CAUDAL

Question 6

Frontal lobe

Answer 6

Involved in action

Question 7

Area 4

Answer 7

M1
Most directly involved in controlling movement

Question 8

Area 6

Answer 8

Lateral premotor cortex

Question 9

SMA and pre-SMA

Answer 9

Supplemental motor area

Question 10

Pre-motor cortex/SMA

Answer 10

Control organization and control of movements

Question 11

Motor cortex controls ipsilateral or contralateral muscles?

Answer 11

Contralateral

Question 12

Individual motor neurons fire…

Answer 12

Just before and during movement

Question 13

Reciprocal connections b/w the parietal lobe and the premotor cortex mediate…

Answer 13

Sensory-motor transformations

Question 14

Sensory-motor transformations

Answer 14

The computations that enable sensory info to guide interactions w objects in the environment

Question 15

What network is involved in directing arm movements towards objects

Answer 15

Parietal, dorsal premotor cortex and M1

Question 16

Peripersonal spatial map

Answer 16

Used to guide goal-directed movements
Many neurons in parietal lobe respond to both tactile and visual stimuli with receptive fields that are spatially in register
These neurons are thought to be involved construction of a peripersonal spatial map

Question 17

Ventral premotor neurons (vPMC) respond to…

Answer 17

preferred shapes

Question 18

Mirror neurons

Answer 18

Discovered in premotor cortex.
Respond when monkey reaches for an object AND when he watches the experimenter reaches for the object
They do not respond to the object alone or to non-goal directed movements of the experimenter’s arm

Question 19

Do primary motor cortex neurons activate contralateral and/or ipsilateral motor neurons?

Answer 19

Contralateral

Question 20

Do premotor cortex neurons activate contralateral and/or ipsilateral motor neurons?

Answer 20

Can be both!

Question 21

When do premotor neurons fire?

Answer 21

During movements and during an imposed delay prior to the movement
This suggests they are involved in planning and preparation to move
CUE ——– REACH

Question 22

When do neurons in primary motor cortex fire?

Answer 22

Before and during voluntary movements of contralateral muscles

Question 23

Monkey: Cue vs reach

Answer 23

Pre-motor neuron goes nuts for cue AND for reach, yellow and green dot

Question 24

Mirror neurons respond to …

Answer 24

Purposeful goal directed movements
Understand the intentions of others

Question 25

Mirror neurons in Autists

Answer 25

Not great

Question 26

SMA and pre-SMA

Answer 26

pre-SMA: Linking movement to higher order executive functions Linking together Complex Movement sequences Activating the movement Implicated in internally generated movements/Volitional movements

Question 27

When SMA is damaged...

Answer 27

Alien Limb Syndrome

Question 28

Alien limb syndrome

Answer 28

A limb just acts on its own but does purposeful movements , e.g take of glasses OR loss of spontaneous movement

Question 29

Sequential finger movent

Answer 29

SMA is activated along with hand part of S1 and M1

Question 30

Single finger flexion

Answer 30

Just S1 and M1

Question 31

Mental rehearsal of sequential movement

Answer 31

ONLY SMA gets activated

Question 32

Turn, Push, Pull

Answer 32

SMA neuron is active prior to third movement in the sequence regardless of what the movement is

Question 33

Readiness Potential (Berietschaftspotential)

Answer 33

EEG signal that is recorded before the medial frontal lobes (SMA) of humans Around 1 sec before voluntary movements

Question 34

What region is most directly connected to movement?

Answer 34

M1

Question 35

How much does M1 contribute to cortical motor output?

Answer 35

1/3 of cortical motor output to brainstem and spinal cord Remainder comes largely from premotor cortex, SMA and S1

Question 36

Corticospinal tract

Answer 36

Projections from motor cortex to spinal cord form Corticospinal tract

Question 37

Projections from motor cortex to the brainstem form the...

Answer 37

Corticobulbar tract

Question 38

Cerebral peduncle

Answer 38

Formed by internal capsule

Question 39

Pyramids

Answer 39

Come after cerebral peduncles

Question 40

Pyramidal decusation

Answer 40

fibers cross over to contralateral side

Question 41

Midbrain: Corticospinal tract

Answer 41

Corticospinal tract (cerebral penduncles) At the left bottom and right bottom Very big

Question 42

Pons

Answer 42

Corticospinal tract is more in middle

Question 43

Rostral medulla

Answer 43

Corticospinal tract(cerebral penducles) is at the bottom

Question 44

Caudal medulla

Answer 44

At the bottom

Question 45

Corticospinal tract AKA...

Answer 45

Cerebral penducles

Question 46

Lesioning the pyramids of a monkey...

Answer 46

Monkey will be paralyzed BUT will recover functions EXCEPT it will lose control of individual fingers This indicated that there are alternative parallel pathways for controls of voluntary movement

Question 47

Brainstem

Answer 47

Controls stereotyped movements of the head (e.g facial expressions, chewing, gag reflex) Through descending connections w the spinal cord it contributes to the control of voluntary movements of the body

Question 48

Anything to do with cranial nerves involved in voluntary movements of the head?

Answer 48

Some corticobulbar projections control these

Question 49

Medial brainstem pathways

Answer 49

Innervate axial muscles that control posture and balance Travel down the ventral spinal cord white matter and terminate in ventromedial regions of the cord gray matter 1)Vestibulospinal tract 2)Tectospinal tract 3)Reticulospinal tract

Question 50

Main lateral pathway

Answer 50

Rubrospinal tract

Question 51

What in the brainstem is the origin of the rubrospinal tract?

Answer 51

red nucleus of the midbrain

Question 52

Rubrospinal tract...

Answer 52

Contributes to control of voluntary limb movements

Question 53

Rubrospinal fibers descend...

Answer 53

In the contralateral dorsolateral column of the spinal cord and terminate in the dorsolateral gray matter

Question 54

Spinal cord

Answer 54

Descending projections terminate on spinal cord PREMOTOR neurons or directly on ventral horn motor neurons The direct connections may be especially important for control of individual digits

Question 55

Central pattern generators

Answer 55

Intrinsic circuitry of the spinal cord Walking, swimming fish