neuroscience exam 2 Flashcards
(167 cards)
1
Q
what is the job of the basal ganglia?
A
initiation of mvmt
2
Q
what is the job of the cerebellum?
A
coordination of ONGOING mvmt
3
Q
where do UMNs deliver signal to?
A
brainstem and spinal cord
4
Q
where do LMNs transmit signals to?
A
directly to skeletal muscles
5
Q
where is the cell body of a LMN?
A
in the ventral horn
6
Q
what is a motor unit?
A
an alpha motor neuron and the muscle fibers it innervates
7
Q
where does the alpha motor neuron project to?
A
project to extrafusal muscle
releases ACh to contract them
8
Q
where does the gamma motor neuron project to?
A
intrafusal fibers in the muscle spindle
responsible for proprioception
9
Q
what do extrafusal muscle fibers do?
A
generate force
10
Q
describe intrafusal muscle fibers
A
too small to generate significant force
very very actin/myosin
innervated by sensory and motor
helps detect muscle stretch
11
Q
how are cell bodies of LMNs organized?
A
extensors - anterior
flexors - posterior
distal muscles - lateral
proximal muscles - medial
12
Q
what are some signs of lower motor syndrome?
A
paresis/paralysis
hypotonia/flaccidity
decreased/loss of reflexes
atrophy - more severe than UMN
involuntary muscle contraction
13
Q
define fasciciulations
A
quick twitches
entire motor unit
visible on skin
not always pathologic
if last for days-weeks can be pathologic
14
Q
define fibrillations
A
brief contractions
single muscle fiber
not visible to eye
always pathologic
15
Q
what does the medial corticospinal tract do?
A
controls neck, shoulder, and trunk muscles
16
Q
what does the reticulospinal tract do?
A
control bilateral postural muscles, antigravity and gross limb mvmts
17
Q
what does the lateral vestibulospinal tract do?
A
control postural muscles
maintain COG over BOS in upright position
18
Q
what does the medial vestibulospinal tract do?
A
control neck and upper neck muscles
19
Q
what does the lateral corticospinal tract do?
A
controls selective motor control, fine distal mvmts
isolating one joint
is affected most in stroke/TBI
dr. rawal’s most important - will most likely have ?’s on test
20
Q
what does the rubrospinal tract do?
A
control extension of wrist and fingers
21
Q
what does the lat CS tract pass through between the cortex and the midbrain?
A
internal capsule
22
Q
if there is a lesion at T12 in the right side, which impairments will the person have?
A
DCML: ipsi (crosses above lesion)
ST: contra (crosses after lesion)
lat CS: ipsi (crosses above lesion)
med CS: no effect (does not reach T12)
23
Q
where do fibers project to in the corticobrainstem tracts?
A
CN nuclei in the brainstem
24
Q
are CB injuries ipsi or contra?
A
isolated CN - ipsi
brainstem injury - contra
25
what are the 5 steps between a decision and the skeletal muscle?
neural activity begins with decision in anterior frontal lobe
motor planning areas active, followed by control circuits
control circuits, consisting of cerebellum and basal ganglia, regulate activity in UMN tracts
UMN tracts deliver signals to spinal interneurons and LMNS
LMNs transmit signals directly to skeletal muscles, eliciting a contraction
26
what are examples of UMN syndromes?
tumor
stroke
MS
TBI
CP
ALS
SCI
27
what are examples of LMN syndromes?
ALS
polio
CN injury
bells palsy - CN7
nerve lesion
peripheral neuropathy
28
10 common impairments in UMN lesions
abnormal synergy - mus cannot coordinate
abnormal co-contraction
hyperreflexia
muscle contracture - tightens mus
hypertonia
muscle overactivity
muscle tone - high or low cause weaker mus
myoplasticity
paresis
spasticity
29
what are peripheral nerve?
any nerve distal to spinal nerves
30
what deficits does a lesion in a spinal nerve show?
myotomal/dermatomal distribution
31
what deficits does a lesion in a peripheral nerve show?
peripheral nerve distribution
32
what does the cervical plexus innervate?
cutan info from post scalp to clavicle
anterior neck muscles
diaphragm
33
what does the brachial plexus innervate?
entire UE
34
what does the lumbar plexus innervate?
skin and muscles of ant and medial thigh
35
what does the sacral plexus innervate?
post thigh and most of leg and foot
36
what are 4 signs of peripheral nerve damage?
sensory changes
autonomic changes
motor changes
denervation: trophic changes (pain and temp)
37
what kind of injuries cause mononeuropathy?
trauma
traumatic myelinopathy
traumatic axonopathy
traumatic severance
38
lundborg classification
physiological conduction block, myelin damage
axonal damage
axon + endo damage
axon + endo + peri damage
axon + endo + peri + epi damage
39
sunderland classification
I
II
III
IV
V
40
seddon classification
neurapraxia (transient block)
axonotmesis (lesion in continuity)
neurotmesis (division of a nerve) (stage 3-5 of sunder)
41
what is traumatic myelinopathy?
loss of myelin limited to site of injury
interferes with function of large diameter axons
focal compression is a cause
42
prognosis of myelinopathy
good in cases of focal compression
schwann can remyelinate
43
traumatic axonopathy
disrupts axons
affects all size axons
leaves mye intact
results in muscle atrophy, reduced reflexes, loss of sensation
44
can axons repair?
yes, if support structures are intact
regrowth: 1-2mm/day, 1 inch/month
45
what is axonal sprouting?
intact axons take over
changes in motor unit morphology
46
what happens during traumatic severance?
nerves are physically divided
complete interruption
47
describe repair of severance
requires surgical intervention
prognosis poor
muscle remains viable 12-18 months after denerv
48
what is multiple neuropathy?
2+ parts of the body
individual nerves are affected
random, asymmetrical presentation
diabetes or vascularitis
49
what is polyneuropathy?
involving multiple nerves
symmetrical, progressing distal to proximal
stocking and glove pattern
NOT result of trauma
LMN
50
what are the causes of polyneuro?
toxic
metabolic
autoimmune
therapeutic drugs
51
what is distal symmetrical polyneuro?
length-dependent
distally affected first
not isolated to a pattern
large fiber: sensory ataxia, proprio, vibration loss
small fiber: pain, temp, autonomic dysfuction
52
what are 3 types of acquired polyneuros?
diabetic
alcoholic
drug induced (chemo)
53
what is diabetic polyneuro?
nerve damage not reversible
90% of DM pts present with it
worse at night
54
what is charcot foot?
interaction of multiple factors within DM polyneuro
midfoot collapse with rockerbottom foot
orthotics necessary
55
medical management of DM polyneuro
improve glycemic control
pain treatment challenging
meds: anticonvulsants, antidepressants, opioids
56
PT for DM polyneuro
foot care
education
address balance/gait impairments
exercise
57
describe alcoholic polyneuro
is it due to alcohol or vitamin def
nutrition usually poor
may be reversible
need to abstain from alcohol
58
what is chemotherapy induced polyneuro?
neurotoxic effects of many cancer agents
very similar to DM polyneuro
59
what is genetic polyneuro?
most common is charcot-marie-tooth:
slow prog
many subtypes
dom or recessive
slowly progressive
60
symptoms of charcot marie tooth
high arch
foot drop
slapping gait
loss of muscle in lower legs
numbness in feet
difficulty with balance
later, appear in arms and hands
61
what is guillain-barre syndrome?
polyneuro
paresis may be worse proximally
onset is rapid
treatment required to prevent respiratory failure
recovery of function proceeds proximal to distal
62
diagnosis of polyneuro
eval guides treatment
look for patterns
nerve biopsy
genetic testing
63
electrodiagnostic studies
electrical activity from nerve conduction and EMG studies
64
nerve conduction studies
application of external current and record response from large diameter; myelinated axons
key parameters: latency, velocity, amplitude
65
electromyography
insertion of recording electrode into muscle
key parameters: insertional and rest activity, recruitment activity
66
general guidelines to diagnosing myelin
nerve study latency
nerve conduction velocity
slow nerve conduction
67
general guidelines to diagnosing axons
nerve study amplitude - decrease
electromyography
68
clinical testing
2/3 signs high evidence of peri neuro
absence of ankle jerk
impaired vibration
impaired position sense of great toe
69
treatment of polyneuro
results of sensory, MMT, electrodiagnostic guide
education to prevent complications from damage
70
sensory considerations of treatment
visually inspect areas
proper foot care
balance effects
nightlights for bathroom trips at night
71
motor considerations of treatment
strengthen to prognosis and goals
consider whether pt is reconditioned
orthoses used to stabilize WB joints
72
what is paresis and paralysis?
paresis: partial loss of voluntary contraction
paralysis: complete loss of voluntary contraction
happens in both UMN and LMN
73
when corticospinal tracts are interrupted, which tract helps retain some movement of the upper arm?
reticulospinal
74
what types of muscle atrophy do we see at UMN and LMN?
UMN: disuse from lack of muscle use
LMN: denervation of skeletal muscle - most severe
75
what is impaired selective control?
interruption of lateral corticospinal tract
specific muscles cannot be activated independently
76
what is spasticity?
hypertonia from UMN
abnormally strong resistance to passive stretch
velocity dependent
limits joint ROM
77
what is rigidity?
velocity independent
increase in resistance to stretch
seen in parkinson's (neither UMN or LMN)
78
what is hypotonia?
seen in LMN
abnormally low resistance to passive stretch
79
what is flaccidity?
lack of resistance to passive stretch
complete loss of muscle tone
seen initially in UMN and in LMN
80
what happens to muscle tone when someone has a stroke?
when in initial shock, they will have hypotonia or flaccidity
once they start recovering, it will switch to hypertonia
81
what is the clasp-knife response?
when a muscle is slowly passively stretched and resistance drops at a specific point in ROM
82
what is a medication for spasticity?
botulinum toxin - prevents lower motor neurons from releasing ACh
83
what are the components of a normal reflex?
sensory receptor
afferent neurons
integration
efferent neuron
effector organ
84
describe the stretch reflex
whenever a muscle is stretched, excitation of spindle causes reflex contraction of muscle
85
what are the most common abnormal reflexes?
hyperreflexia
clonus
babinski sign
hyporeflexia
86
what is hyperreflexia?
loss of inhibitory corticospinal input combined with enhanced excitability of LMN response
excessive firing of LMN
postive - prevents muscle atrophy
87
describe clonus
involuntary, repeating, rhythmic
sustained clonus is always pathological
lack of UMN control
count to 10 and documents 10+ beats
88
describe babinski sign
extension of great toe, accompanied by fanning of other toes
stroke lateral sole of foot from heel to ball of foot
89
what is myoplasticity?
adaptive structural changes within a muscle in response to changes in NM activity
90
describe ALS
affects both UMN and LMN
onset between 40 and 70
20% more common in men
90% without family history
excessive glutamate
sensory will be normal
91
what is guillain barre syndrome?
acute inflam and demy of peripheral fibers
good prognosis, eventually recover but may have some degree of weakness
2-3 weeks after mild infection
may need hospital for respiratory help
92
what are common infections that kickstart GBS?
campylobacteriosis
mycoplasma
pneumoniae
epstein barr
varicella-zoster
zika
93
what is the onset pattern of GBS
rapid onset, plateau then gradual recovery
symmetrical motor loss distal to proximal
recover proximal to distal
94
which CN does GBS affect?
7, 9,10
95
treatment for GBS
plasmapheresis
intravenous immunoglobulin therapy
PT and OT rec
avoid overworking muscles
facilitate resolution of respiratory problems
orthotics
96
tips to take care of feet
check everyday
wash everyday
smooth corns and calluses gently
trim your toenails straight across
wear shoes and socks always
protect your feet from hot and cold
keep blood flowing to feet
get foot check every dr visit
97
which cranial nerves have autonomic functions?
3, 7, 9, 10
98
what is the path of transmission of the olfactory nerve?
nasal receptors
olfactory bulbs
olfactory cortex in the insula
99
how often do olfactory cells undergo replacement?
30-90 days
100
what parts of the limbic system receive olfactory input?
amygdala - emotional response
hypothalamus - odor affects hunger
hippocampus - judgement and decisions involving smell
101
summary of olfactory nerve
special sensory
afferents for olfaction
102
how does the optic nerve work?
light strikes the retina and is converted into neural signals by photosensitive cells
info is carried by optic nerve
103
what part of the thalamus is involved in vision?
lateral geniculate
104
summary of optic nerve
special sensory
vision
afferents for pupillary and accommodation reflexes
105
what is accommodation?
how good your lens acommodates near/far vision
106
how would you test the optic nerve?
vision charts
107
what are the 3 motor nerves of the eye?
oculomotor
trochlear
abducens
108
what are the 6 extraocular muscles and their innervation?
lateral rectus - abd - 6
medial rectus - add - 3
inferior rectus - down - 3
superior rectus - up - 3
inferior oblique - extorsion (ER) - 3
superior oblique - intorsion (IR) - 4
109
what are the other muscles of CN 3?
levator palpebrae superioris - lifts eyelid
pupillary sphincter muscles/iris muscles
ciliary muscles - changes shape of lens
110
what is synergistic action related to eye muscles?
coordination between the two eyes
111
what controls head and eye coordination?
MLF
the eyes will follow the head
112
what CN does the MLF include?
3, 4, 6, 8, 11
113
what are the parasym functions of CN 3?
constriction of the pupil
pupillary reflex: constriction of the pupil in the eye directly stimulates by bright light
consensual reflex: constriction of pupil in the other eye
accommodation reflex: contraction of muscles controlling the lens of eye
114
summary of oculomotor nerve
motor:
moves eye up, down, medial, elevates eye lid
parasym:
consensual and accommodation reflexes
115
summary of trochlear nerve
motor
moves eye medially and down (superior oblique)
116
summary of abducens nerve
motor
abducts eye (lateral rectus)
117
what is the masseter reflex?
masseter is tapped with reflex hammer, muscle contracts
118
what is corneal reflex?
when cornea is touched, eyes close
119
what is the swallowing reflex?
food touching entrance of pharynx elicits mvmt of soft palate and contraction of pharyngeal muscles
120
what do the sensory fibers of the trigeminal nerve do?
transmit info to face and TMJ
121
what do the motor fibers of CN5 do?
innervates muscles of mastication, tensor tympani
122
what are the three branches of CN5?
ophthalmic
maxillary
mandibular
123
summary of trigeminal
somatosensory:
afferents for touch, proprio, pain, temp info from face, ant 2/3 of tongue, sinuses, teeth
motor:
muscles of mastication
reflex:
afferent for corneal
aff and eff for masseter
124
where do the bilateral signals from cortiobrainstem project?
upper facial nerve nucleus to upper facial muscles
125
where do the contralateral signals from cortiobrainstem project?
lower facial nerve nucleus to lower facial muscles
126
what if there is a lesion right below the facial nerve nucleus?
ipsi issues
upper and lower face on that side
LMN
127
what if there is a lesion right above the facial nerve nucleus?
contra lower face
UPM
upper is ok because bilaterally innervation
128
what is bell's palsy?
LMN, paralysis of ipsi side of face
cause unknown
129
what can you do in therapy for someone with facial paralysis?
train expressions
cards to copy
facial massage
130
summary of facial nerve?
somato:
aff for sensation from anterosuperior ear and external ear canal
vis:
aff taste from ant 2/3 of tongue
motor:
eff for muscles of facial expression and stapedius
parasym:
eff to lacrimal, nasal and salivary glands
(except parotid salivary gland)
reflex:
eff to corneal
131
what are the two branches of the vestibulocochlear nerve?
vestibular: head position and mvmt
cochlear: hearing
132
what is the vestibulocochlear reflex?
helps stab visual images during head mvmts
133
auditory pathway
external ear through auditory canal
ossicles vibrate
mvmt displaces fluid in the cochlea
sound waves transmitted from external and middle ear to inner
bending of cilia changes membrane potential
depol opens ca channels
release glutamate and transmit info to cns
134
what does the medial geniculate body do for auditory function?
thalamic relay station
provides conscious awareness and rec of sounds
135
what does the inferior colliculus do for auditory function?
Orients head and eye to sound
detect location of sounds
136
what does the reticular formation do for auditory function?
increases activity level throughout CNS
activating effect of sounds
137
what are the three cortical areas for sound info?
primary auditory: intensity of sound
secondary auditory: memories of sound
wernicke's area: comprehension of spoken
138
summary of CN 8
special sen:
aff for head position and mvmt
hearing
reflex:
aff for vestibe-occular reflex
139
what CN does taste from post 1/3 of tongue?
glossopharyngeal
140
summary of CN 9
sen:
aff from pahrynx, soft palate, middle ear, external ear canal
motor:
eff to stylopharyngeal muscle
autonomic aff:
aff from post 1/3 of tongue, blood pressure, chemical info from carotid artery, taste from post tongue
autonomic eff:
parotid gland
reflex:
aff limb of gag and swallow reflex
141
summary of vagus
sen:
aff from pharynx, larynx, skin in external ear
motor:
eff to muscle of phar and lar
vis:
aff from phar, lary, thorax, abdo
parasym:
eff to smooth muscle and glands
reflex:
eff of gag and swallow
142
summary of CN 11
motor:
eff to SCM and traps
143
summary of CN 12
motor:
eff to intrinsic muscles and extrinsic muscles of tongue
144
what CN are involved in the oral stage of swallowing?
5
7
8
10
12
145
what CN are involved in the phar and lar stage of swallowing?
9
10
146
what CN are involved in the esophageal stage of swallowing?
10
147
what CN are involved in speaking?
5
7
10
12
148
define neuroplasticity
ability of neurons to change in function, structure, chemical profile
basis for new motor skills, rehab, new cog skills
149
what is habituation?
technique intended to decrease neural response to a stimulus
ST
simplest forms of NP
150
how often are habituation activities performed?
5-10 reps, 5x/day
focus on smaller reps, but more often per day to be effective
pts should stop and wait for 5-10 seconds if they get dizzy
151
what is positioning vertigo?
pt experiences dizziness/unsteadiness with certain position changes
152
what is motion sensitivity?
symptoms of disorientation/dizziness with busy visual environment
example: driving at night
153
what is long term potentiation?
silent synapse to active synapse
increasing potential
154
what is long term depression?
active synapse to silent synapse
less likely to depolarize
155
what is an example of experience dependent plasticity?
body-weight supported treadmill training
156
what are stepping pattern generators?
when a person initiates walking, signals are sent from brain to SPG in the spinal cord
mvmt of lower limb coordinated by anterior commissure
157
what additional neural control is required for walking?
postural control
cortical control of DF
afferent info to adapt mvmt to environment
158
what is excitotoxicity?
cell death caused by over excitation of neurons
159
what is collateral sprouting?
denervated neuron attracts side sprouts from nearby undamaged axons
160
what is regenerative sprouting?
injured axon issues side sprouts to form new synapses with undamaged neurons
161
why might axon regeneration not occur in CNS?
glial scars
release many different growth inhibiting factors
limited or absence of nerve growth factor
162
4 examples of synaptic mechanisms
recovery of synaptic effectiveness
- when edema goes down, function resumes
denervation hypersensitivity
- more sensitive so it can stay alive
synaptic hypereffectiveness
- the working terminal is more effective to maintain function
unmasking of silent synapses
- comes out of dormancy
163
what is transcranial magnetic stimulation?
can enhance or inhibit motor learning and memory formation
164
effects of rehab on plasticity
no known drug provideds neuroprotection
recovery influenced by intensity and timing
early rehab is necessary
too rigorous can be counterproductive
165
what is task specific training?
produces long lasting cortical reorganization
induces more regular patterns of brain activation
repetitive practice of functional tasks
166
what is constraint-induced mvmt therapy?
restrain good hand to use affected hand
6 hrs a day for 10-15 days
167
principles of neuroplasticity
use it or lose it
use it and improve it
specificity
repetition matters
intensity matters
time matters
salience matters - functionally relevant
age matters
transference - one can enhance the other
interference - one can interfere with others
