Neuro 29 Brainstem-Spinal Systems

Front 1

what are the 3 brainstem spinal systems

Back 1

vestibulospinal (MLF and lateral)
reticulospinal (medial and lateral)
rubrospinal: ONLY flexor pathway

**from the brainstem centers to the spinal cord

Front 2

what is the only brainstem spinal system that carries into to flaxors

Back 2

Rubrospinal

**keep in mind the corticospinal also carries flexor info but its not a brainstem thing

Front 3

what are the 2 parts of the vesibulospinal system and what info to they carry? where do they arise

Back 3

MLF: UE, BL
Lateral Vestibulospinal: LE. IL

**motor info to extensors of UE nad LE

**arise from medial and lateral vestibular nuclei accordingly

Front 4

what vestibulospinal system has axons that descent BL?IL?

Back 4

MLF: fibers descend BL, but predominate in the IL side, project to the UE

Vestibulospinal: fibers descend IL to the LE

Front 5

do the vestibular nuclei receive descending info from the cerebral cortex? where do they get info from

Back 5

NOPE

Inhibitory: cerebellar cortex,

Excitatory: cerebellar nuclei, CN VIII

Front 6

where do MFL fibers originate?
what info do they carry?
where do they carry it to? where is it located in the SC? are fibers carried UL or BL?
Synapse

Back 6

Originate: medial AND inferior vestibular nuclei
Carry: motor to Extensors on UE
Located in the MLF, sort of midline anterior
BL but predominate on IL side
Synapse: on EXTENSOR aMN nad gMN in ant part of ant horn

Front 7

does the MLF control extensors in the LE? what does

Back 7

nope, they only projecto to extensors in the UE

Lateral vestibular nucleus

Front 8

what vestibulospinal tract runs the entire length of the SC, what does this mean about the structires it innervates

Back 8

extensor mm of UE and LE

**compare to MLF that does just UE

Front 9

so typically the cerebellar cortex gives info to descending tracts, what brainstem sc path doesnt receive cerebral cortex input? what input does it reveice

Back 9

vestibulospinal

Gets ++ from CN VIII and cerebellar vuclei
Gets - - from Cerebellar cortex

Front 10

is there 1 or 2 reticulospinal tracts?
are they IL or BL?
how far do they extend?
what mm do they activate?

Back 10

2: lateral (medullary reticular formation) and medial (pontine reticular formation)
IL
extend all the way throughout the SC
activate extensors (all brainstem/SC do extensors except for rubrospinal)

Front 11

where do medial reticulospinal fibers arise and what mm do they influence

Back 11

pontine reticular formation
EXCITE extensors (contrast to the lateral reticularspinal which inhibits extensors)

Front 12

what reticulospinal tract inhibits extensors? what activates them?

Back 12

Inhibit: medial (pontine)
Excite: lateral (medullary)

Front 13

so both the pontine nad medullary reticulospinal tracts get info from the cortex via what path? is there info from anywhere else?

Back 13

Corticoreticular

**pontine also gets info from ALS

Front 14

the ALS dieliers info to what brainstem/SC tract

Back 14

pontine reticulospinal

**medial

Front 15

the pontine and hte medullary reticulospinal, what is excitatory, what is inhibitory. what are they exciting or inhibiting?

Back 15

Pontine: excitatory (its high, its excited) it gets inco from ALS

Medullary: inhibits

**extensors of UE nad LE

Front 16

are hte reticulospinal system paths pretty obvious in the brainstem

Back 16

nope, but in the sC they can be ID

Front 17

so the medullary reticulospinal receives info from where? what does it do with it?

Back 17

excitatory from cortex
synapse in inhibitory interneuron
inhibits extensors

Front 18

the pontine reticulospinal receives info from where? what does it do with it

Back 18

excitatory from cortex
excitatory from medulla
synapse to excitie extensors

Front 19

the rednucleus is the origin of what? is this path IL or BL? what mm do they influence

Back 19

rubrospinal tract

CL! the fibers decusate in the midbrain, immediate after they leave red nucleus

UE FLEXORS

Front 20

what is the origin of the rubrospinal? is this a CL or BL path? what mm are influenced

Back 20

red nucleus

CL, fibers decusate immediatly after it leaves the rednucleus

UE FLEXORS

Front 21

the rubrospinal gets input from where?

Back 21

cerebral cortex
cerebellar nuclei

**both influence FLEXIOn of the UE

Front 22

what is the path of the rubrospinal where does it get info from? waht does it influence

Back 22

info from cerebral cortex nad cerebellar nuclei goes to the red cortex, it decusates in the midbrain and carries excitatory info to FLEXORS of the UE on the CL side

Front 23

does hte robrospinal do LE flexors

Back 23

npope, just CL UE

Front 24

what path gets input from the cerebellar nuclei and the cerebral cortex

Back 24

rubrospinal

**info goes to red nucleus and decusates there to the CL side and carries CL info to Flexors of the UE

Front 25

what is the decorticate posture
decerebrate?

Back 25

arms flexed
rest of body extended

**entire body extended

Front 26

what leision is more anterior decorticate or decerebrate?

Back 26

Decorticate: flexed UE (cerbellar nuclei input to rubrospinal at the rednucleus)

Decerebrate: lower, fully extended. (cut at the level of the red nucleus so rubrospinal no longer receives info from cerebellar nuclei)

Front 27

what leision is above the level of the red nucleus, what does this lead to

Back 27

decorticate, the higher leision. this leads to flexed UE and extended LE


**recall the red nucleus is the landmark for the rubrospinal path. when the cut is above the red nucleus there is still info from the cerebellar nuclei that comes in to the rednucleus and lets the UR flexors activate

**ALS still brings + to LE extensors

Front 28

what leision gives flexed UE, what is totally extended

Back 28

Decorticate: Flexed UE

Decerebrate: totally extended

Front 29

when we have a decorticate leision is it above or below the red nucleus?

what allows the arm positioning
what allows the LE positioning

Back 29

above (cerebellar nuclei input to rubrospinal is in tact)

UE: FLEXED bc the red nucleus still receives info from the cerebellar nuclei

LE EXTENDED bc the pontine reticulospinal track receives ALS info to + the extensors of the LE

Front 30

when we have a decerebrate leision is it above or below the level of the red nucleus

what does htis mean for UE
what does htis mean for LE

Back 30

below (no rubrospinal input)

UE: no longer receives info from the cerebeallar nuclei, no flexion stmulis is given

LE: the ALS still delivers + info to Extensors so the entire body is extended via pontine reticulospinal

Front 31

name the leision

"flexor a motor neurons are influenced by the rubrospinal tract, the ALS influences the pontine reticulospinal path

Back 31

decorticate, leision ABOVE red nucleus

**flexed arms
**extended LE

Front 32

name the leision

"extensor gamma MN are directly excited by pontine reticulospinal input"

Back 32

decereibrate, leision at the level of the red nucleus

**totally extended.

Front 33

if there is progression from decorticate (flexed arms) to decerebrate (extended arms) what does htis indicate

Back 33

bad news

**hemmorage may be descending brainstem, may enter respritory and cardio centers and life support may be needed

Front 34

extensor gamma motor neurons are excited by _______ and inhibited by _______

Back 34

pontine reticulospinal
medullary reticulospinal

Front 35

flexor aMN are influenced by ________ and __________ tracts.

Back 35

corticospinal
rubrospinal