Brainstem; Medulla Flashcards
lesion of corticospinal fibers above the pyramidal decussation
contralateral motor deficit
lesion of corticospinal fibers below the pyramidal decussation
ipsilat motor deficits (ie in the SC)
lesion of STT in medulla
contralat loss of pain and temp sensation from body
1st order neurons of the dorsal column
DRG
gracile and cuneate fasciculi carry what info
epicritic sensation
- conscious proprioception and fine touch
unilateral lesion of FC and FC in medulla at the level of the pyramidal decussation
ipsilateral loss of fine tough and prorioception
spinal nucleus of V
brainstem continuation of dorsal horn, but input from trigeminal n. from face via Spinal tract of V
contains 2nd order nuerons
relay info -> contralateral VPM
info; protopathic; temp, pain, crude touch
spinal nucleus of V, relays what type of info where?
protophathic info from face (pain, temp, crude touch)
to; VPM nucleus of the thalamus
via; STT
lesion of spinal nucleus of V or spinal tract of V
ipsilateral loss of pain and temp sensation form the face
loss of blink relfex (afferent limb)
sensory decussation
axons from 2ndary sens neurons in gracile and cuneate nuc decussate as internal arcuate fibers and become the medial lemniscus
lesion above the pyramidal decussation
contralateral UMN symptoms
(spastic paralysis, babinsky respons, hemiparethesis)
contralat loss of epicritic info from body
lesion of CN XII
hypoglossal n
impsilat weakness, fasciculations, and ipsilat deviation of tongue upon protrusion
medial lemniscus =
axons of 2ndary sensory neurons in contralat gracile & cuneate nuclei
internal arcuate fibers =
decussating sensory fibers before they form the medial lemniscus
lesion of medial lemniscus
contralat loss in conscious prop and fine touch info
somatotopy of medial lemniscus
info from lower limb = ventrally
info from upper limb = dorsally
(the man standing)
lateral (accessory) cuneate nucleus
relays unconscious info from upper limbs -> cerebellum
spinal nucleus of V, spinal tract of V
trigeminal n input from face
protopathic pain (pain, temp, crude tough)
to contralateral VPM nucleus of thalamus
Via; STT
lesion of spinal nucleus and tract of V
ipsilateral loss of pain and temp sensation from face
loss of blink reflex (afferent limb - sensory)
role of inferior olivary nucleus
beleived to play a role in motor learning via its connections (climbing fibers) with the cerebellum
lesion of CN XII
hypoglossal nerve
LMN signs
ipsilat deviation of the tongue
solitary nucleus and tract recieves
general visceral sensation and special gustatory info
lesion of salitary nucleus and tract
ipsilateral loss of taste sensation
medial and inferior vestibular nuclei, lesion
part of balance control system
imbalance, nystagmus away from the lesion and dizziness
dorsal and ventral cochlear nuclei, lesion
1st relay for auditory info forom cochlear n
ipsilat loss in hearing
lesion of inferior cerebellar peduncle
cerebellar ataxia (lack of vol coor of mmm mvmts) hypertonia (ab increase in mm tension)
the STT travels with what other tracts?
spinomesencephalic
spinoreticular tract
all together these 3 = anterolateral system or spinal lemniscus
locations of VSCT crossings
1st ventral white commissure
2nd superior cerebellar peduncle
medullary reticular formation
contributes to several functions;
sleep-arousal cycle, motor control, regulation of visceral activity
origin of MRST
the medullary reticulospinal tract originates from the nnucleus gigantocellularis and terminates in spinal cord
main function of MRST
facilitate flexor motor neurons
inhibit extensor motor neurons
nucleus ambiguus
motor neurons controlling pharynx and larynx muscles
dorsal to inf olive w/in medullary reticular formation (difficult to id)
lesion of nucleus ambiguus
loss of gag reflex (efferent limb)
horse voice and dysphagia
lesion of the pyramid in the open medulla
-above the decussation;
contralat motor deficit
somatotopy of the medial lemniscus in the medulla
oriented vertically
ventral - Lower limb (epicritic info)
dorsal - Upper limb (epicritic info)
(epicritic info = fine touch/proprioception)
unilateral lesion of the medial lemniscus
contralat loss in proprioception and fine touch sensation from the body
origin of the tectospinal tract
neurons in the superior colliculus
function of the tectospinal tract
involved in the reflex of orientation of the head in response to visual, auditory, and somesthetic stimuli
medial longitudinal fasiculus
ascending and descending tracts involved in control of head/neck mvmt and coordination of the vestibulo ocular reflex
(located; dorsal (above) tectospinal tract, which is above the medial lemniscus)
unilat lesion of vestibular nuclei
imbalance
nystagmus away from the lesion
dizziness
lateral vestibulospinal tract
LVST
descends to all spinal cord
faciliates MN controlling Antigrav Extensor mm
medial vestibular nucleus
origin of medial vestibulospinal tract MVST
terminates at C and high T levels to control head/neck in relation to gravity
dorsal and ventral cochlear nuclei
1st relay for Auditory info entering via the cochlear nerve
unilateral lesion of cochlear nuclei
ipsilat loss in hearing
inf cerebellar peduncle
includes many tracts - all cerebellar
spinal nucleus and tract of V
carry pain and temp sens from face
lesion of spinal nucleus and tract of V
ipsilat loss of pain and temp sens from the face
loss of blink reflex (afferent - sens limb)
function of VSCT
provides the cerebellum with a motor copy (eff copy) of what the spinal motor neurons are being told to do
medullary reticular formation
cont to sleep-arousal cycle, motor control, reg of visceral activity
nucleus perpositus
involved in the control of eye mvmts (higher up in the midbrain aboveish the hypoglosseal nuc)
lesion of the gracile or cuneate nucleus
ipsilat loss of epicritic info
