week 12 Flashcards
ascending pathways are important in assessing
gait, cerebellar function, postural responses, prognosis
all sensory modalities come into CNS via
aferent neurons
some afferent neurons initiate
relfexes
all ascending pathways travel up cord to reach
brain
most ascending pathways synapse on
ascending projection neurons
some travel directly from
cord to brain
afferent modalities important to us
nociception and proprioception
all ascending pathways start at
a receptor
ascending pathways are _____
pseudounipolar, GP, GSA
most ascending pathways synapse on
neuron in dorsal gray horn (interneuron for reflex or ascending projection neuron to brain)
location of ascending pathways in spinal cord
in dorsal and lateral funiculi (especially superficially in lateral);
why could this placement be a problem
compression; afferent damaged first
there are ____ proprioceptive tracts
9
conscious tracts travel to
thalamus, then parietal lobe
unconscious tracts travel to
cerebellum
are pelvic limb tracts more superficial or less superfacial than other prsts
more superficial
unconscious proprioception is composed of how many tracts
5
all unconscious prprioceptive tracts carry proprioceptive information to
cerebellum (from same side of body to same side of cerebellum)
dorsal and ventral spinocerebelar tracts are both from
pelvic limb
both travel up the _____ into cerebellumc
caudal peduncle
dorsal spinocerebrellar on
same side
ventral spinocerebellar on
opposite side; but crosses back in cerebellum
cuneocerebellar, rostral spinocerebellar and cervicospinocerebellar tracts all carry information from
thoracic limbs
which ones do not synapse on APN
cuneocerebellar tract
fasciculus cuneous
lateral part of dorsal funiculus in which the cuneocerebellar tract travels; travels up caudal peduncle into cerebellum
rostral spinocerebellar and cervicocerebllar tracts cary info from
thoracic limbs and neck
how many major conscious proprioceptive tracts are tehre
4
conscious proprioceptive tracts ultimately carry information to
parietal lobe
conscious afferent proprioceptive neurons dont synapse in
cord
all conscious proprioceptive tracts traevl to
medulla to snapse on interneurons; interneurons will ascend brainstem in a specific tract
pathway of conscious proprioceptive tracts
to mthalamus, relay neuron, pareital lobe
conscious propreioceptive tract cross over?
yes
fasciculus gracillis carries
conscious proprioception from pelvic limb on same side to medulle; synapse on interneurons
where do fasciculus gracillis axons cross
rostrally in medulla lumniscus
fasciculus cuneatus
pretty much same as px
spinomedullary tract carries info from
pelvic limbs
spinocervicothalamic tract
all four limbs and flank
doesa lall conscious proprioception croos in medulla
yes
what to look for with ataxia
hea, neck, body posture
limb placement
wide stance
limb movement: too high or not high enough?
compressive cord lesions include
herniated disc
tumor vertebral
large fibers function in
proprioception
large fibers signs with increasing compression
proprioceptive deficis
progonosis when large fibers comrpressed
good
medium sized fibers function in
voluntary movement
signs with increasing compression of medium sized fibers
paresis, paralysis
prognosis of paressis, paralysiss
fiar
small fiber size function
superficial pain
signs of increasing compression of small fibers
loss of cutaneous sensation
prognosis of small fiber compression
fair
extra small fiber function
deep pain
prognsosis with extra small fiber compression
poor
nociception is used for
prognosis; not localization
if deep pain is present after trauma
90-95% chance of restoring some function
deep pain absent after trauma
5-10% chance
disc herniation deep pain absent
more than 5-% change
mosat important tract in ma is the
lateral spinothalamic tract; (1p0% crossover)
in domestics, travel
all nocicpetive tracts scattered in all funcuiculus
pain from head
trigeminal nerve to trigeminal ganglion to pons
fibers in spinal tract of CN V synapse on
neurons in nucleus spinal tract of CN V
Axons from CN V travel
to thalamus, internal capsule, parietal lobe
unilateral forebrain lesion
fairly normal pain sensation from limbs/trunk (may see controlateral)
CN V crossover
100%
normal mentation starts in
brainstem
reticular ____
formation
all sensory projection neurons feed into
reticular formation
neurons from RF send axons to
thalamus
relay neurons from thalamus send fibers to
all cerebral cortical areas
ascending reticular activating system keeps cortex ____
awake “seat of consciousness”
to see changes in mentation with forebrain lesion, must be
severe and/ or diffuse (generalized)
gait
how an animal moves
what is needed for gait
all components of NS needed (spinal cord, brainstem, vestibular and cerebellar)
to walk normally you need
brainstem (umn centers) cerebellum vestibular system proprioceptive tracts UMN tracts LMN tracts muscles
distinguish neurological cases from
musculoskeletal
what is tone
small amount of muscle contraction
tone is under control of
muscle spindles
sensitivity of spindles under control of
UMN
UMN are inhibitory to
Gamma efferents without UMN
wihtout umns, spindles are
super sensitive
how is tone assessed
by palpating all muscle groups
assessment of extensor muscles
can they bear weight?
hopping and hemiwalking
sway test
compression of withers/croup
flexor muscles
withdrawal relfex (hold on to foot and assess strength)
postural responses go to
forebrain
in unilateral forebrain disease, deficits on
opposite side
one umn center in forebrain responsible for
adjusting posture
all postural responses use
afferent neurons (GP) ascending proprioceptive tracts forebrain and cerebellum descending UMN tracts LMN (GSE) muscles
are postural responses useful in localizing lesions
no
proprioceptive positioning
support weight of animal so doesnt lose strength
knuckle paw over and set in place on dorsum (normal animal will quickly reposition paw)
proprioceptive positioning horse
can pick up foot and drop it, catch foot; can watch feet going over curbs
hopping
support animal so all weight is on one limb;
support abdomen in hand and pull hind limbs off ground
then support one thoracic limb
hopping
shift dog to make sure weight is on midline
hop laterally and forward
medially doesnt work well;
also tests strenght
hopping in horse
cant support weight but can hop them
wheelbarrowing tests
tests everything from T2 cranially
wheelbarrowing
support animals pelvic limbs
walk forward on thoracic limbs
look for normal movement and symmetry
then, pick up head so they cant see feet
extensor postural thrust
hands under thoracic limb
slowly lower pelvic limbs
animal should take steps backward
look for extension of pelvic limbs
wheelbarrowing in horse
walk horse down hill
extensor postural thrust
lift limbs on one side
walk animal away from you (laterally)look for normal symmetrical movement
also tests strength
extnesor postural thrust in horse
can grab halter and tail, and push away from you
placing
do tactile first blind fold/cover eyes bring dorsum of paw to edge of table once paw makes cantact they shuld pick up paw and place on table then do visual difficult to pick up deficits
tonic neck
elevate head and should see hindlimb flexion and forelimb extension; lower head and should see opposite;
tonic neck utilizes
vestibular system
horse tonic neck
cant do
righting
if annimal is up and walking, you know they can right themselves
sway test
can you sway him by pulling tail to one side
