Neuro- Descending Motor Pathways

Front 1

Motor Cortex location in frontal lobe

Back 1

back end of frontal lobe

Front 2

Precentral Gyrus

Premotor Cortex

Supplemental Motor Area

Back 2

motor strip, primary motor cortex
PreMC-in front of precent. refines motor mvmt
SMA-top, medially- refines motor mvt

Front 3

Raw Motor output

Refineries

Back 3

Precentral Gyrus (motor cortex)

Basal Ganglia and Cerebellum

Front 4

what type of neruons are in the CST and motor cortex areas?

Back 4

Upper Motor Neurons

Front 5

where is the CST at the decussation of the pyramids?

Back 5

CST winds up in the dorsal part of lat funiculus

goal=talk to alpha motor neuron

Front 6

Homunculus

Back 6

mouth- lateral
feet/legs- medial

Big Lips/Face/Hands-a lot dedicated to these parts

Front 7

3 Homunculi

Back 7

1. precentral gyrus
2. postcentral gyrus
3. Premotor Cortex

Front 8

Brodman's Areas

Back 8

dfft parts of cortex w/ dfft histological differences

Front 9

Neocortex


3layered piece

Back 9

cortex is primarily 6 layers


Hippocampus, more ancient

Front 10

Layer 5

Back 10

most important
contains Betz cells
main pyramidal cells, give rise to CST

Front 11

Brodman Area 4

Back 11

precentral gyrus (primary motor cortex-PMC). main motor output.
CST/CBT

control individual mvmt of muscles

Front 12

Force of Contraction and Timing of Contraction are dependent on?

Back 12

relative to what is happening in the cortex

Front 13

Force


Timing

Back 13

freq of firing of individual Betz Cells

M1 UMN from precent gyrus. neuron to muscle contraction has lag (ms)

Front 14

Brodman Area 6

Back 14

Pre Motor Cortex (PreMC)
refines motor mvmt, controls complex mvmt

Front 15

Timing: PreMotor Neruon fires when?

Back 15

before the M1 (main motor neuron)

Front 16

Main outputs of PreMC (area 6)


what inputs INTO PreMC

Back 16

1. Main=Area 4
2. some directly to ventral horn
3. some to reticulspinal path
-axial and prox musc

*Posterior Parietal Cortex

Front 17

Fxn of Post Parietal Cortex

Back 17

1. input into PreMC
2. fxn in Tone (Gamma MN)
3. goes to reticulospinal neurons

Front 18

Supplemental Motor Area(SMA)
-location, brodman area

Back 18

medial aspect of hemisphere
still brodman area 6
-just like PreMC

Front 19

function of SMA (MII) neurons

anomaly of SMA

Back 19

motor planning
precedes firing of PreMC
just thinking of moving will fire MII

Front 20

what is the SMA in close prox to

Back 20

the limbic lobe

Front 21

Flow of Timing of motor firing

Back 21

1. SMA (MII)
2. PreMN
3. MI
4. Contraction

Front 22

Primary Motor Cortex neurons (PMC) receive input from

5/7

Back 22

1. SMA (MII)
2. PreMC
3. Primary Sensory Areas
4. Post Parietal
5. Thalmus VA/VL
-also receives
6. Cerebellum
7. Basal Ganglia

Front 23

UMN
LMN
MOTOR UNIT

Back 23

in cortex
in ventral horn
LMN+all the muscle cells it innervates

Front 24

EMG can detect


at rest
max act

Back 24

diseases of LMN and UMN
recording needle in muscle itself

bomp,bomp,bomp
shhhhhhhhhhh

Front 25

Denervation


ALS

Back 25

neve damaged or alpha motor neuron is dead

can have damage to both LMN/UMN

Front 26

what happens when a muscle cell is denervated?

Back 26

secrete substances that attract nearby intact nerve endings
other nerves can reconnect that muscle cell

Front 27

if renervation doesnt happen, 2 things are possible....

Back 27

1. fibrillations
2. fasiculations

Front 28

Fibrillation

Back 28

muscle atrophy/shrinkage occurs
use EMG
NOT visible to naked eye

Front 29

Partially denervated muscle

Back 29

at rest, get fibrillations (positive sharp waves)
tic intermittent at rest
NOT visible
need EMG

Front 30

sick/dieing motor neuron that is STILL connected to muscle...

Back 30

muscle will be irritated-fires on its own

==>Fasiculations

Front 31

Fasiculations

Back 31

visible to naked eye
represent irritated/sick motor unit
do NOT need emg
seen in ALS or Polio before you see atrophy

Front 32

when do i need an EMG?

when do i not need an EMG

Back 32

to see fibrillations

to see fasiculations

Front 33

Fasiculations of the Tongue

Back 33

seen in ALS
skeletal hands
very weak
will become a serpintine tongue after wasting

Front 34

NMJ

Back 34

no phys contact
rel Ach

Front 35

what does the muscle tissue do to accomodate the NMJ?

Back 35

microscopic indendations to inc surface area of receptors

Front 36

what happens to jxnl folds in M.G.?

Back 36

they flatten out
amt of Ach rec is decreased

autoimmune disease to Ach rec

Front 37

Botulinum Toxin

large portion
small portion

Back 37

clostridium botulinum

fools the buton into taking it in
protease that eats a docking protein

Front 38

botulinum toxin

Type A
Type B

Back 38

all small portions are protenacous

cut synaptobrevin(VAMP)
cut SNAP25

Front 39

effects of botulinum toxin..

Back 39

neuron cant rel Ach anymore
terminal does not fxn
grows rootlets to reattach

Front 40

symptoms of LCST lesion

Back 40

contralateral body weakness
lose fine motor control
lose contralateral lower face
lose contralateral tongue (CBT)

spare axial muscles(VCST)

Front 41

Lesion to PreMC

Back 41

slow jerky movements
difficult in visually guided tasks

*very rare*

Front 42

what usually accompanies a preMC lesion?

Back 42

a concurrent lesion to PMC

Front 43

Lesion to SMA results in

Back 43

Apraxia
losing your motor memory

Front 44

What is perseverative behavior and what is it associated with?

Back 44

repeating motor tasks over and over

assoc w/ lesions to SMA

Front 45

Normal Pressure Hydrocephalus

Back 45

NPH=Apraxia
pressure is abnormal during sleep
pressure bangs up against ventricles and hits lets/bladder

Front 46

3 Ws of NPH

Back 46

1. wacky- forgetful, not psychotic
2. wet- loss of bladder fxn
3. wobbly- more of an apraxic gate, espec when starting to walk

Front 47

what do NPH patients appear to be like? exception....

whats another name for apraxic gate?

Back 47

Parkinson's Patients
NO TREMOR

magnetic gate

Front 48

treatment for NPH

Back 48

put a shunt in to relieve night-time CSF pressure spikes

small window of opportunity

Front 49

Lesion to Post Parietal Cortex(PPC)

Back 49

rare to have motor complaints if just PPC. but usually with PMC
Hemi-neglect arm/leg
ususally nondominant hemi, so left hand neglected

Front 50

Parietal Lobe controls what

Back 50

3-Dimensional Space map

Front 51

Premotor for eyes is called what?

Back 51

Frontal Eye Fields (FEF)
infront of homunc for eyes

Front 52

what does the FEF talk to?

Back 52

to PPRF on opp side
PPRF talks to ipsiVI + contraIII
allows eyes to work laterally

Front 53

what gets from PPRF to opposite CNIII?

Back 53

MLF-medial long fasiculus
lesion in lft MLF->problems w/ left CNIII

Front 54

look laterally, problem with medial rectus in lft eye, converge and everything is ok. what is this called?

Back 54

Intranuclear opthlmolegia(IOP)

Front 55

usual areas affected in MCA stroke

Back 55

1. FEF
2. precentral gyrus
3. postcentral gyrus

Front 56

is person is looking AWAY from paralyzed side, what does that mean?

Back 56

they are looking toward damaged cortex

Front 57

if damage is in pons w/ pyramidal fassicles affected, person is looking toward damaged side, why??

Back 57

if lesion in Lft Pons, hitting Lft CST. rt side paralyzed

look to right b/c lft PPRF is damaged- lft lat rectus gone
and lft MLF is damaged- rt med rectus is gone--->therefore eyes look right

Front 58

Posturing

Back 58

associated with damage right after pathways have left the cortex
Bilateral
Herniation-pushing brain down
decerebrate or decorticate

Front 59

Decorticate

Back 59

happens first. closer to cortex
motor lesion of IC or cortex
spastic hemiplegia
flexion
'looks like an O'

Front 60

Decerebrate

Back 60

lesions b/w red nuc and vestib nuc
gamma rigidity
hyperpronation and extension

Front 61

is the CST all motor?

Back 61

NO
40% Betz cells from Area 4
20% from Area 6
40% from PPC
*some sensory is in CST

Front 62

CST path

Back 62

post limb of IC
ducussates at pyramidal dec
80-90% crosses to lateral funiculus
10-20%stays Ipsi in ventral funiculus
down to ventral horn of SC

Front 63

Corticobulbar Tract (CBT)

Back 63

Area 4 and Area 6
pass thru Genu of IC
goes to all motor nuclei in brain stem
gets most bilaterally

Front 64

lesion of CBT

Back 64

lower face paralysis
sometimes contralat tongue

Front 65

Corticorubral Tract


what is the main output of CRT?

Back 65

Areas 4+6
UMN for Red Nuclei
-part of Mollaret's Triangle
Rubrospinal Tract

Front 66

Rubrospinal Tract

Back 66

crosses and goes to
1. torso
2. head
3. upper arm
facilitates upper limb flexor MN

Front 67

where does the RubroST synapse

Back 67

on interneurons in Rexed Laminae 5, 6, and 7
primarily of cervical cord

its a little VENTRAL to LCST in lateral funiculus

Front 68

what pathway is cervical dystonia associated with?

Back 68

person's head is twisted
Rubrospinal Tract

Front 69

Corticoreticular pathway

Back 69

Area 4+6
post limb of IC
synapse on pontine and medullary reticular fomrations Bilat

Front 70

Reticulspinal Tract synapses where

Back 70

Rexed Laminae 7, 8, 9

goes to torso, head, and forearm alphaMN

Front 71

Primary involvement of Reticulospinal tract

Back 71

gama tone and reflexes
preganglionic sympathetic neurons in CV regulation
-via talking to IMLCC

Front 72

what is near the Reticulospinal tract in the SC

Back 72

overlaps with Spinothalamic Tract
pain illicits racing heart rate and inc BP

Front 73

which pathways have direct control over movement?

Back 73

Corticospinal (CST)
Corticobulbar (CBT)
Corticorubral
Corticoreticular

Front 74

which paths modulate motor performance via neural loops involv cerebellum and BG

relay paths

Back 74

corticothalamic
corticostriatal
corticopontine