Primary Motor Areas

Question 1

Where is the primary somatosensory cortex located

Answer 1

Behind the central sulcus

Question 2

Where is the primary motor cortex located

Answer 2

in front of the primary motor cortex

Question 3

What is in front of the MI

Answer 3

Premotor area and the supplementary motor area

Question 4

Motor control is ___

Answer 4

distributed! It is not just one area!!! It is distributed across many areas

Question 5

Cerebral cortical contributions to behavior (in relation to motor bx) includes

Answer 5

1 Fractionation
2 Speed, agility, accuracy, adaptability to goal - directed motor bx
3 Refined motor learning and enhanced motor performance in skilled tasks

Question 6

What tract - fractionation

Answer 6

lateral corticospinal tract

Question 7

UMN - cell bodies where

Answer 7

cortex or brainstem

Question 8

UMN - cell bodies in cortex - axons project to

Answer 8

LMN/IN in spinal cord

or Brainstem LMN

Question 9

UMN - cell bodies in brainstem - axons project to

Answer 9

LMN in spinal cord

Question 10

UMNs are classified how

Answer 10

according to where they travel/end up in the spinal cord - medial vs. lateral
NEVER send axons directly to peripheral nerve

Question 11

LMN - cell bodies where

Answer 11

in spinal cord or brainstem

Question 12

LMN - axons synapse where

Answer 12

directly on mm fiber (ventral root of peripheral nerve)

Question 13

Two types of LMN

Answer 13

alpha and gamma

Question 14

Alpha LMN cell bodies in

Answer 14

ventral horn SC, extrafusal mm, large cell bodies, myelinated axons

Question 15

Gamma LMN cell bodies in

Answer 15

Ventral horn SC, intrafusal, smaller

Question 16

Alpha-gamma coactivation

Answer 16

crucial for normal mm spindle function

Keeps the mm spindle ready to sense stretch at any moment in time

Question 17

MN pools =

Answer 17

Group of LMNs in the ventral horn, axons project to a single muscle

Question 18

Medial pools project to

Answer 18

Proximal mm

Question 19

Lateral pools project to

Answer 19

Distal mm

Question 20

Anterior pools project to

Answer 20

Extensors

Question 21

Posterior pools project to

Answer 21

Flexors

Question 22

UMN tracts for posture

Answer 22

MEDIAL
1 Tectospinal
2 Medial corticospinal 
3 Medial reticulospinal
4 Medial/Lateral vestibulospinal

Question 23

Tectospinal tract starts where

Answer 23

Midbrain (sup colliculus)

Question 24

Function of tectospinal tract

Answer 24

Mvmnt of head towards sound of moving objects

Question 25

Medial corticospinal tract starts

Answer 25

cortex SMA, PMA, MI

Question 26

Medial corticospinal tract function

Answer 26

COntrol of neck, shld, trunk, anticipatory postural adjustment

Question 27

Medial Reticulospinal tract start

Answer 27

pons (reticular formation)

Question 28

Medial reticulospinal tract function

Answer 28

postural mm, limb extensors, APAs

Question 29

Medial/Lateral vestibulospinal start

Answer 29

medulla and pons (vestibular nuclei)

Question 30

Medial/lateral vestibulospinal goal

Answer 30

med - bilaterally to neck and upper back | lat - extensors (anti gravity)

Question 31

UMN tracts for fast, goal directed movement

Answer 31

LATERAL 1 LCST 2 Rubrospinal 3 lateral reticulospinal

Question 32

LCST - start

Answer 32

cortex SMA, PMA, MI

Question 33

LCST - function

Answer 33

contralateral, fractionation of mvmnt | Hand mvmnt**

Question 34

Rubrospinal tract - start

Answer 34

Midbrain (red nucleus)

Question 35

Rubrospinal tract - function

Answer 35

contralateral UE, gross movement

Question 36

Lateral reticulospinal - start

Answer 36

medualle in reticular formation

Question 37

Lateral reticulospinal - function

Answer 37

facilitates flexors and inhibits extensors

Question 38

Premotor cortex - function

Answer 38

involved in planning of visually guided movement - catching a ball

Question 39

Supplementary motor area - function

Answer 39

involved in planning of bimanual, sequential, more motivated mvmnts, getting up from chair to walk to door

Question 40

MI gets input from

Answer 40

``` SMA Premotor Primary somatosensory cortex Post parietal cortex Basal ganglia and Cerebellum via thalamus ```

Question 41

MI project to

Answer 41

brainstem, spinal cord, cerebellum, basal ganglia

Question 42

__% of LCST axons originate in MI | Synapse where

Answer 42

40 | Ventral horn

Question 43

Corticomotoneurons

Answer 43

Monosynaptic projectiosn from layer 5 to spinal motor neurons, and Ia inhibitory interneurons - IMPORTANT FOR FRACTIONATION

Question 44

MI sends a copy to where

Answer 44

efferent copy to cerebellum of what is going to happen

Question 45

Layer 5 of the motor cortex - cells

Answer 45

pyramidal cells this is why the tracts can be called pyramidal These neurons send their axons down and out!

Question 46

Results of study with visual stimulus and trained/learned MI, Premotor, SMA

Answer 46

MI - fired both from visual and trained PM - only with visually cued sequence SMA - only with trained or learned sequence

Question 47

PMA - gets a lot of input from where

Answer 47

posterior parietal cortex!, prefrontal cortex

Question 48

SMA gets a lot of input from where

Answer 48

Prefrontal cortex, basal ganglia

Question 49

PMA vs. SMA | which is visually guided and which is internally generated

Answer 49

PMA - complex and elegant reaching/grasping system, visually guided movement SMA - tuned to intention - selecting and executing actions deemed appropriate or withholding actions

Question 50

Where are mirror neurons

Answer 50

PMA

Question 51

PPC - integrates what

Answer 51

vision with somatosensory

Question 52

PMA - signaling to motor cortex says

Answer 52

here is the object, here is the direction and then projects to hand/arm areas of the MI

Question 53

Evidence for mirror neurons

Answer 53

Monkey study that shouwed activation when watched another monkey but also when watched a hum

Question 54

Precision grip/Power grip study

Answer 54

Motor cortex - there is not just a single motor neuron to mm connection Motor cortex represents functional tasks - not specific mm

Question 55

Motor cortex codes for

Answer 55

direction and force | does so from an emerged property of many cells together - this is why horizontal connections are so important