Neuro Flashcards
(305 cards)
1
Q
Gyri vs sulci?
A
Gyri are ridges/folds
Sulci are grooves
2
Q
What is the microscopic organisation of the cerebral cortex?
A
Layers and columns
3
Q
What is the basis of cytoarchitecture?
A
cell size
spacing/packing density
layers
4
Q
Functions of the frontal lobe?
A
Motor function Language motor aspects Cognitive functions eg planning atttention memory
5
Q
Parietal lobe functions?
A
Sensations
Language sensory aspects
Spatial orientation
Self perception
6
Q
Occipital lobe function?
A
Processing visual info
7
Q
Temporal lobe function?
A
Auditorty processing
emotions
memories
8
Q
What structures make up the limbic lobe?
A
Mamillary body
Amygdala
Cingulate gyrus
Hippocampus
9
Q
What are the functions of the limbic lobe?
A
Learning
memory
emotion
motivation and reward
10
Q
where is the insular cortex found?
A
deep in lateral fissure
11
Q
What are the functions of the insular cortex?
A
Visceral sensations Autonomic control Interoception Auditory processing Visual-vestibular integration
12
Q
Describe the internal structure of the cerebral cortex
A
grey matter - neuronal cell bodies and glial cells
white matter - myelinated neuronal axons in tracts
13
Q
What are the three types of fibres in white matter tracts?
A
Association
Commissural
Projection
14
Q
What do association fibres connect?
A
connect areas in same hemisphere
15
Q
What do commissural fibres connect?
A
connect homologous structures in left and right hemispheres
16
Q
What do projection fibres connect?
A
connect cortex with lower brain strcutures
17
Q
what are the 4 association fibres? what do they connect?
A
superior longitudinal fasciculus - frontal → occipital
arcuate fasciculus - frontal → temporal
inferior longitudinal fasciculus - temporal → occipital
uncinate fasciculus - anterior frontal → temporal
18
Q
What are the three types of projection fibres?
A
afferent - towards cortex
efferent - away from crotec
corona radiata - deeper to cortex
19
Q
Where do projection fibres converge?
A
through internal capsule between thalamus and basal ganglia
20
Q
What are three differences between primary and secondary/association cortices?
A
Primary : have predictable functions, organised topographically, left and right symmetry
21
Q
What are the three frontal lobe motor areas?
A
primary
supplementary
premotor
22
Q
What are the functions of the primary motor cortex?
A
controls fine, discrete, voluntary movements
descending signals
23
Q
What are the functions of the supplementary and premotor area?
A
Planning complex movements
s - internally cued
pm - externally cued
24
Q
What are the two parietal lobe areas?
A
primary somatosensory
somatosensory assoication
25
What are the functions of the primary somatosensory cortex?
process somatic sensations from body receptors
| eg. touch, vibration, pain, temp, etc.
26
What are the functions of the somatosensory association?
interpret significance of sensory information
| self awareness and of personal space
27
two areas of the occipital lobe and their functions?
primary visual cortex - process visual stimuli
| visual association - interpretation and meaning of visual input
28
two areas of the temporal lobe and their functions?
primary auditory cortex - process auditory stimuli
| auditory association - interpretation and meaning of auditory input
29
functions of the prefrontal cortex?
```
attention
social behaviour
planning
personality
decision making
```
30
functions of Brocas area?
production of language
31
function of wernickes area?
understanding language
32
what would you observe in a frontal lobe lesion?
personality change
| inappropriate behaviour
33
what would you observe in a parietal lobe lesion?
contralateral neglect i.e. lack of awareness of self and extraperosnal space on opposite side
34
what would you observe in a temporal lobe lesion?
agnosia
| anterograde amnesia
35
what is agnosia?
inability to recognise objects
36
what is anterograde amnesia?
cannot form new memories
37
what would you observe in a lesion to broca's area?
expressive aphasia - slurred speech but able to understand speech
38
what would you observe in a lesion to wernicke's area?
receptive aphasia - can speak but cannot comprehend speech
39
what would you observe in a primary visual cortex lesion?
blindness in corresponding visual field
40
what would you observe in a visual association lesion?
prosopagnosia (face blindness)
| unable to interpret visual information
41
two types of imaging to assess cortical function?
PET - positron emission tomography
| fMRI - functional magnetic resonance imaging
42
what does PET look at?
Blood flow directly to brain region (take up of glucose using radioactive isotope)
More glucose uptake = more brain activity
43
what does fMRI look at?
the amount of blood oxygen in a brain region
44
What can you use to measure evoked/event-related potentials?
EEG
| MEG
45
two methods of brain stimulation?
transcranial magnetic stimulation (TMS)
| transcranial direct current stimulation (tDCS) to increase or decrease neuronal firing rates
46
two types of imaging to assess cortical structure?
diffusion tensor imaging (DTI) based on diffusion of water molecules
DTI with tractography to assess neuronal tracts
47
Where in the skull is the ear found? How is this beneficial?
The petrous part of the temporal bone. It's v hard so provides the necessary protection
48
name 3 functions of the outer ear?
to capture sound and direct it to the tympanic membrane
to amplify sound via resonance
protection via hairs and wax
49
How does the middle ear amplify sound?
vibrations move from the tympanic membrane w a large surface area to the oval window (smaller sa) via the ossicles → sound pressure increases and it is amplified
50
name the 3 ossicles?
malleus
stapes
incus
51
why does sound need to be amplified in the middle ear?
bc the sound waves are moving from air in the middle ear to fluid in the inner ear where it is more difficult for sound waves to travel
52
what is the function of the cochlea?
to transduce sound waves to electrical impulses that can be interpreted by the brain
allows pitch and volume to be analysed
53
describe the structural components of the cochlea
```
scala vestibuli (contains perilymph)
scala media (contains endolymph)
basilar membrane
organ of cortisol
scala tympani
```
54
how is the basilar membrane arranged? what does this mean?
Tonotopically (think xylophone)
narrow and thicker at the base compared to the apex
means the base can receive higher frequencies and thE apex lower ones
55
what cells does the organ of corti contain and how are they arranged? functions?
Inner hair cells - one column (fewer), sound transduction
| outer hair cells - three columns, modulate sensitivity, amplify sound
56
what are the hair cells connected to?
tectorial membrane (only OHC in constant contact)
57
what are the hairs on hair cells called?
sterocillia
58
how do the Scala vestibuli and the Scala tympani communicate?
helicotrema
59
explain how sound is transduced?
sound travels through perilymph of scala vestibule and scala tympani
causes basilar membrane to vibrate → tectorial membrane is pushed against hair cells → stereo cilia are deflected → potassium channels open → potassium from endolymph enters hair cell → cell depolarises → calcium enters through VGCCs → glutamate vesicle exocytosis → glutamate to afferent nerve → auditory cortex
60
what happens in transduction of louder sounds?
theres more deflection of steroecilia and more potassium channels open leading to greater depolarisation
61
describe the auditory neural pathway
nerves from hair cells → spiral ganglia → vestibulocochlear nerve → ipsilateral cochlear nuclei → superior olive in brainstem (bilateral) → inferior colliculus → medial geniculate body → auditory cortex
62
human range of hearing?
20 - 20000 Hz
| 0 - 120 dB
63
Which frequencies are affected first
higher frequencies
64
what is a tuning fork used for?
to establish the probable presence or absence of hearing loss with a significant conductive component
65
what are the two tuning forks tests?
```
weber test (over the head)
rinne test (next to ear)
```
66
what is pure tone audiometry?
science of measuring acuity for variations in sound intensity and frequency
67
what device is used in PTA? how are results measured?
audiometer
| audiogram
68
What does the central processing assessment assess?
Hearing abilities other than section
| Verbal and non-verbal testing
69
What is tympanometry?
testing the condition of the middle ear and the mobility of the tympanic membrane and the ossicles
does this by creating varying pressures in the ear canal
70
What are otoacoustic emissions?
low intensity sounds produced by outer hair cells in the cochlea when they expand and contract
71
When are OAEs measured?
Newborn hearing screening
| Hearing loss monitoring
72
3 methods of measuring auditory evoked potentials?
Electrocochleography (cochlea and CN8) 0.2-4.0ms
auditory brainstem response (CN8 and brainstem nuclei and tracts) 1.5.10ms
late responses (primary auditory and association cortex) 80-500ms
73
Benefits of auditory brainstem response?
objective
patients doesn't need to pay attention
most commonly used in clinics
74
when are cortical potentials useful?
In neurological conditions or processing problems
75
name and describe the 3 types of hearing loss
conductive - outer or middle ear problem
sensorineural - inner ear or auditory nerve
mixed - conduction and transduction are affected
76
causes of conductive hearing loss?
outer ear - foreign body or wax buildup (cerumen impaction)
| middle ear - otitis or otosclerosis
77
causes of sensioneural hearing loss?
inner ear - presbycusis or ototoxicity
| nerve - CN8 tumour
78
what is presybycutis?
loss of outer hair cells, occurs with age
79
4 types of hearing loss treatment?
Underlying cause (eg. remove earwax)
Cochlear implant
Hearing aids
brainstem implant
80
How do hearing aids work?
amplify sound
81
How does the cochlea implant work?
Replaces hair cells → receives and analyses sound → transforms it to electrical signals → auditory nerve
(requires functional nerve)
82
When can a brainstem implant be used?
When auditory nerves are damaged
electrical signals sent directly to electrodes in brainstem
very risky
83
what are the 3 inputs of the vestibular system?
visual
proprioceptive
vestibular
84
vestibular system outputs?
reflexes to help maintain posture and a stable gaze
85
where is the vestibular system found?
in the posterior region of the inner ear
86
what does the vestibule consist of?
three semicircular canals - anterior , lateral and posterior
| all 3 connected (via ampullae) to utricle which is joined to the saccule by a conduit
87
What are the hairs on vestibular hair cells called?
Stereocillia and kinocilium ( the biggest cilia)
88
When are vestibular cells depolarised?
when endolymph is moved via head movement
89
what are the otolith organs? what do they consist of?
utricle and saccule
| carbonate crystals that help deflect hairs
90
what are the maculae? how do they differ in the utricle and the saccule?
hair cells → gelatinous metric → otoliths
saccule is placed vertically
utricule is placed horizontally
91
outline the structure and contents of the semicircular canals
canal contains potassium rich endolymph
ends in ampulla which opens into utricle
ampulla has crista where hair cells are found
hair cells are surrounded by the cupula
92
what is the function of the cupula?
helps movement of hair cells in ampulla of semicircular canals
93
where do primary vestibular afferents end?
vestibular nuclei
| cerebellum
94
where do vestibular nuclei project to? (4)
spinal cord
extraocular muscle nuclei
cerebellum
CV and respiratory control centres
95
where is the main vestibular cortex found?
parietal lobe as parieto-insular vestibular cortex
96
3 main functions of the vestibular system?
control posture
detect and inform about head movements
keep images fixed during movement
97
why do neurons still fire at the resting potential of hair cells? what do you call this discharge?
Because there is the force of gravity and information that you are stationary is still being processes
Required to keep you upright
Basal discharge
98
what are the three hair cell potentials in the vestibular system and how are they generated?
Resting - always there
Excitaion - occurs when sterocilia move towards the kinocilium → depolarisation → ↑ nerve discharge
Inhibitoin - stereo cilia move away from kinocilium → hyperpolarization → ↓ nerve discharge
99
What do the otolith organs detect?
Tilt and linear acceleration
utricule - horizontal movement
saccule - vertical movement
100
What does the semilunar canals detect? And how?
angular acceleration
| endolymph flow moves the cupula which then moves hair cells
101
how do opposite semicircular canals work?
lateral work together
| anterior of one side works with posterior of opposite side
102
what are the two main vestibular reflexes?
vestibul-ocular reflex
| vestibule-spinal reflex
103
Describe the VOR and how it works?
connects the vestibular and oculomotor nuclei
keeps images fixed in the retina
the eyes move in the opposite direction to the head but at the same velocity and amplitude
104
Describe the VSR and how it works?
from vestibular nuclei:
motor neurones to the limbs via the lateral tract
motor neurons to the neck and back via the medial tract
controls posture and prevents you from falling
105
what 7 things are considered in vestibular assessment?
```
anamnesis (history)
posture & gait
cerebellar function
eye movements
vestibular tests
imaging
symptoms & impact assessment
```
106
what are the main symptoms of a balance disorder?
vertigo (objects spinning)
| dizziness
107
2 main types of balance disorders?
peripheral & central vestibular disorders
108
give 4 examples of peripheral vestibular disorders
```
vestibular neuritis (acute)
benign paroxysmal positional vertigo (intermittent)
Meniers disease (recurrent)
unilateral and bilateral vestibular hypofunction
```
109
explain bppv
benign paroxysmal positional vertigo
crystals detach from gelatinous matrix in the utricle which move to the ampulla of the canals and put extra pressure on the cupula making you feel dizzy
110
give 3 examples of what can cause central vestibular disorders
stroke (acute)
MS (progresive)
tumour eg schwanoma (progressive)
111
differentials for dizziness? (7)
```
heart disorders
orthostatic hypotension
presyncopal episodes
psychological
gait problems
anaemia
hypoglycaemia
```
112
What can have 'modest symptomatic benefit' in the early stages of dementia?
Acetylcholinesterase inhibitors
113
Name 4 common differentials for dementia
Depression
alcohol related brain damage
vitamin b1/6/12 deficiency
endocrine disorders
114
define preclinical dementia?
there is deterioration in neurological cells but no clinical symptoms yet
115
risk factors for dementia? (7)
```
ageing
oral health
brain trauma
genetics
mid-life obesity
↓ physical activity
infections/ systemic inflammation
```
116
define dementia
severe loss of memory and other cognitive abilities which lead to impaired daily functions
117
what 3 examinations can you carry out if you suspect dementia?
neurological (i.e. testing cranial nerves)
mini mental state exam
addenbrookes cognitive exam
118
what would you see on an MRI where the patient has dementia?
dilated ventricles
atrophied hippocampus
wider sulci and narrower gyri
119
what 2 proteins present in the brain are associated with AD?
B amyloid
| tau
120
what is the management of dementia? (5)
acetlycholintesterase inhibitors
treat behavioural and psychological symptoms eg. w/ antidepressants and antipsychotics
monitor progression
occupational therapy/social services
121
2 defining features of vascular dementia?
associated w/ cerebrovascular diseases
| step wise deterioration
122
3 features of Lewy body dementia?
parkinsonian features
fluctuating cognition
visual hallucinations
123
2 features of FTD?
behavioural changes
| progressive non-fluent aphasia
124
what is the head-turning sign in dementia patients?
they turn to partner/relative because they are unsure/don't know the answer
125
what protein is associated with Lewy body dementia?
a-synuclein
126
outline the production. of tears?
parasympathetic efferent nerves use Ach
tears produced by lacrimal gland, drain through 2 punch into superior and inferior canaliculi into tear sac and exit via tear duct into nasal cavity
127
what is the function of the tear film?
maintains smooth cornea air surface
oxygen supply to cornea
removes debris
bactericide
128
what's the structure of the tear film?
3 layers
superficial lipid layer - reduce tear film evaporation
aqueos layer
mutinous layer on corneal surface - surface wetting
129
what is the conjunctiva?
thin. transparent tissue that covers outer surface of eye (starts at cornea, covers visible eye and inside of eyelids)
nourished by tiny blood vessels
130
what are the 3 layers of the eye? (outer to inner)
sclera
choroid
retina
131
what is the sclera?
outer coat of the eye, protective
| high water content
132
what is the cornea? structure and function?
transparent
low water content
powerful refracting surface - 2/3 eye focusing power
```
5 layers:
epithelium
bowman membrane
stroma
descemets membrane
endothelium
```
133
what is the uvea?
vascular coat of eyeball
between sclera and retina
iris, ciliary body and choroid
134
what is the iris? function?
controls light levels inside eye
opening in centre → pupil
has tiny muscles which dilate/constrict pupil
135
structure and function of the lens?
outer acellular capsule
regular inner elongated fibres - transparency
refractive power - 1/3 of eyes focusing power
accommodation
elasticity
136
what happens when lenses lose transparency?
cataracts form
137
function of the retina?
capturing light rays that enter the eye
138
structure and function of the optic nerve?
electrical impulses from retina to brain
connects to eye near macula
visible part = optic disc
139
what is the blind spot?
where optic nerve meets retina - no light sensitive cells
| optic disc
140
structure and function of the macula?
centre if retina, temporal to optic nerve
responsible for detailed central vision eg. reading
fovea is the centre of macula
141
what is the proportion of cell types at the fovea?
highest concentration of cones, low of rods
142
how is central vision assessed? what is loss called?
visual acuity assessment
| loss of foveal vision = poor visual acuity
143
how is peripheral vision assessed? what does loss lead to?
visual field assessment
| loss of visual field = unable to navigate
144
what is the structure of the retina?
outer - photoreceptors detect light
middle - bipolar cells, local signal processing
inner - retinal ganglion cells , transmit from eye to brain
145
2 types of photoreceptors and differences?
rod cells - more sensitive to light (more pigment, higher spatial and temporal summation) , slow response, night/scotopic vision, more numerous, peripheral
cone cells - faster response, fine & colour vision (photopic), central
146
different cone cell types and colours?
S - blue
M - green
L - red
147
what is the commonest form of colour blindness?
deuteranomaly - don't perceive the colour red
148
what is full colour blindness called?
achromatopsia
149
what test can be used for red green colour blindness?
Ishihara test
150
what is emmetropia?
adequate correlation between axial length and refractive power, parallel light rays fall on retina
(normal)
151
what is ametropia?
mismatch between axial length and refractive power
| parallel rays don't fall in retina
152
types of ametropia?
hyperopia
myopia
astigmatism
presbyopia
153
what is myopia? symptoms? causes?
parallel rays converge anterior to retina (near sightedness)
blurred distance vision → squint → headache
excessive long globe (axial myopia)
excessive refractive power (refractive myopia)
154
treatment for myopia?
diverging lenses
contact lenses
remove eye lens to reduce refractive power
155
what is hyperopia? symptoms? causes?
parallel rays converge at a point posterior to the retina (far sightedness)
blurred near vision, can be intermittent, worse when tired
eyepian, headache, burning sensation
excessive short globe (axial hyperopia)
insufficient refractive power (refractive hyperopia)
156
what can uncorrected hyperopia leas to?
amblyopia (lazy eye)
157
treatment for hyperopia?
converging lenses ± cataract extraction
contact lenses
intraocular lenses
158
what is astigmatism? cause? symptoms?
paralle rays focus in 2 lines
hereditary
refractive media is not spherical
headache, eyepain, blurred distorted vision, head tilting/turning
159
treatment for astigmatism?
regular :
cylinder lenses ± spherical lenses
surgery
irregular:
rigid cylinder lenses
surgery
160
what is the near response triad?
adaptation for near vision
pupillary miosis (constriction) with sphincter pupillae to increase depth of field
convergence with medial recti
accommodation with circular cillary muscles contracting → ↑ refractive power (lens thickens)
161
what is presbyopia?how is it corrected?
naturally occurring loss of accommodation
onset ≥40yrs
distant vision fine
corrected w reading glasses (convex lens) to ↑ refractive power
162
what are the types of optical correction?
contact lenses
intraocular lenses
surgical - keratorefractive or intraocular
163
what is the visual pathway from the eye to the visual cortex?
eye (1st&2nd order) → optic nerve (3rd order) → optic chiasm (half fibres cross) → optic tract → lateral geniculate nucleus (fibres synapse) → optic radiation (4th order) → primary visual cortex in occipital lobe
164
which fibres cross in the optic chiasma?
those from nasal retina - temporal visual field
165
what visual field defects occur if theres a lesion anterior to the optic chiasm? eg. optic nerve compression
only one eye affected - whole visual field affected
166
what visual field defects occur if theres a lesion at the optic chiasm? eg. pituitary tumour
damages crossed fibres (nasal retinal fibres)
| → bitemporal hemianopia
167
what visual field defects occur if theres a lesion posterior to the optic chiasm? eg right sided stroke
affects right temporal fibres and left nasal fibres → left homonymous hemianopia (right temporal and left nasal fields affected)
168
how does homonymous hemianopia with macular sparing occur?
stroke affecting primary visual cortex
| maculae receive blood supply from posterior cerebral arteries on both sides
169
what happens to the pupil when exposed to light? how is it mediated?
constriction (miosis) mediated by parasympthateic nerve in CN III → circular muscles contract
decreases glare
increases depth of field
reduces bleaching of photopigments
170
what happens to the pupil when exposed to dark? how is it mediated?
pupillary dilation mediated by sympathetic nerves → radial muscles contract
↑ light sensitivity → more light can enter eye
171
what is the pathway of the pupillary reflex?
rod& cone photoreceptors → bipolar cells → retinal ganglion cells → optic tract → lateral geniculate nucleus → edinger-westphal nuclei → occulmotor nerve efferent → ciliary ganglion → short posterior cilliary nerve → pupillary sphincter
172
direct vs consensual reflex?
```
direct = constriction of pupil of the light stimulated eye
consensual = constriction of pupil of the other eye
```
173
afferent vs efferent defects and affects in eye?
afferent defect eg damage to optic nerve → no constrcition of either pupil when damaged side is stimulated with light, normal contraction in both eyes when other side is stimulated
efferent defect eg. CNIII lesion, no constriction on affected side no matter which side is stimulated. unaffected side will constrict regardless
174
how can a relative afferent pupillary defect be tested for?
swinging torch test
175
2 different types of eye movement?
saccade - short fast burst
| smooth pursuit - slow movement
176
different types of saccade?
reflexive
scanning
predictive
memory guided
177
what direction does the superior oblique move the eye?
down and out
| trochlear nerve
178
what direction does the inferior oblique move the eye?
up and out
179
what is levoversion and dextroversion?
levo - eyes both move to left, left abduction, right adduction
dextro - eyes both move right
180
symptoms of third nerve palsy?
occulmotor affcvetd → superior, inferior, medial rect & inferior oblique
eye is down and out (unopposed superior oblique and lateral rectus)
droopy eye lid (levator palpabrae superioris)
181
symptoms of sixth nerve palsy?
eye cannot abduct (no lateral rectus) → deviates inwards
| double vision
182
what is the optokinetic nystagmus reflex?
useful in testing visual acuity in preverbal children
| smooth pursuit & fast phase reset saccade
183
what happens when theres damage to the posterior colliery ganglion? what is it known as?
tonically dilated pupil - Adie's pupil
| parasympathetic fibres have no effect
184
what is pilocarpine?
muscarinic receptor agonist on M3 receptors in iris sphincter muscle → miosis
(independent of parasympathetic nerves)
185
explain Adie's pupil?
light-near dissociation
damage to posterior cilliary ganglion → ↑ regulation of postsynaptic receptors in iris instead of ciliary body → more meiosis with accommodation than with light
186
manoeuvres for BPPV?
epley and semont manouvers
187
3 main blood supply arteries to the brain?
vertebral artery
| internal and common carotids
188
circle of willis?
vertebral arteries → basillar artery → posterior cereal → posterior communicating → middle cereal & internal carotid → anterior cerebral →anterior communicating
189
4 types of brain haemorrhage?
extra dural - arterial, trauma esp @ pterion
subdural - venous, trauma
subarachnoid - circle of willis, ruptured aneurysm
intracerebral - spontaneous hypertensive
190
what is a cerebrovascular accident?
rapidly developing focal disturbance of brain function of presumed vascular origin and go ≥24hrs
thromboembolic or haemorrhagic
191
how does a TIA differ from a CVA?
it resolves completely within 24 hours
192
infraction vs ischaemia?
degenerative changes in tissue following artery occlusion vs
| lack of sufficient blood flow → permanent damage if blood flow not restored
193
5 risk factors for stroke?
```
age
smoking
hypertension
cardiac disease
diabetes
```
194
symptoms of an anterior cerebral artery stroke?
paralysis of contralateral structures
abulia → disturbance of intellect, judgement
loss os appropriate social behaviour
195
symptoms of middle cerebral artery stroke?
contralateral hemiplegia
contralateral hemisensory defects
hemianopia
aphasia if L sided lesion
196
symptoms of posterior cerebral artery stroke?
```
homonymous hemianopia
visual agnosia (cannot recognise objects)
```
197
why can you get a headache with a subdural bleed?
build up of intracranial pressure
198
sy,tpoms of a cerebellar lesion?
wobbly eye movements
ataxia
broad hesitant gait
slurred speech
199
what are the major motor descending tracts?
pyramidal : (pass though medulla pyramids), voluntary, motor cortex to spinal cord
corticospinal
corticobulvar
```
extrapyramidal: involuntary, brainstem nuclei to spinal cod
vestibulospinal
reticulspinal
tectospinal
rubrospinal
```
200
function of the primary motor cortex?
precentral gyrus
| fine, discrete, precise voluntary movements
201
function of the premotor area?
anterior to primary motor cortex
planning movements
regulates externally cued movements
202
function of supplementary motor area?
anteriomedial to primary motor cortex
planning complex movemnts, internally cued
active prior to voluntary movement
203
difference between anterior and lateral corticospinal tracts?
anterior - trunk, decussate in spinal cord
| lateral - limbs, decussates at medulla
204
function of the vestibulospinal tract?
stabilise head
coordinate head and eye movements
postural adjustments
205
function of the reticulospinal tract?
from medulla and pons
changes in muscle tone
postural stability
206
function of the tectospinal tract?
superior colliculis to midbrain
| orientation of head and neck during eye movements
207
function of the rubrospinal tract?
from red nucelus of midbrain
| innervate LMNs of flexors of upper limb
208
signs of an UMN lesion?
negative :
loss of voluntary motor function - paresis or paralysis
```
positive :
loss of inhibitory descending inputs
spasticity
hyperreflexia
clonus
babinskis sign
```
209
what is apraxia? lesion? causes?
disorder of skilled movement
lesion in SMA/premotor cortex
stroke and dementia
210
signs of an LMN lesion?
```
weakness
hypotonia
hyporeflxia
muscle atrophy
fasiculations - visible twitches
fibrillations - can be seen on EMG
```
211
signs of motor neurone disease?
same as UMN and LMN signs
dysphagia
dysarthria
nasal speech
212
MND alternative name?
ALS - amyotrophic lateral sclerosis
213
what are the basal ganglia?
```
caudate nucleus
lentiform nucleus (putamen and external globus pallidus)
nucleus accumbens
sub thalamic nuclei
substantia nigra
```
214
what does the striatum consist of?
caudate and putamen
215
function of the basal ganglia?
decision to move
elaborating associated movements
moderating and coordinating movements
performing movements in order
216
pathophysiology of Parkinson's?
degeneration of the dopaminergic neurons that originate in the substantial nigra and project to the striatum
217
signs of parkinsons?
```
bradykinesia
hypomimc face
akinesia
rigidity
tremor at rest
```
218
pathophysiology of Huntington's disease?
degeneration of GABAergic neurons in striatum
| genetic, chromosome 4, autosomal dominant, CAG repeat
219
signs of Huntington's?
```
choreic movements
rapid jerky involuntary movements
speech impairment
dysphagia
unsteady gait
cognitive decline→ dementia
```
220
what is ballism?
from stroke affecting sub thalamic nucleus
sudden uncontrolled flinging of extremities
contralateral symptoms
221
what separates cerebrum from cerebellum?
tentorium cerebelli
222
vestibulocerebellum function?
regulates gait and posture
coordinates head and eye movements
damage = gait ataxia
223
spinocerbellum function?
coordinate speech and limb movements
adjust muscle tone
damage = legs , abnormal gait and stance - usually caused by chronic alcoholism
224
cerebrocerebellum function?
coordinate skilled movements
cognitive function, attention, language processing, emotion control
damage = arms, tremor and speech
225
signs of cerebellar dysfunction?
```
ataxia
dysmetria
intention tremor
dysdiadokinesia
scanning speech
```
226
what are the alpha motor neurons?
LMNs of the brainstem and spinal cord
innervate extrafusal muscles
activation = contraction
227
define motor unit
all the muscle fibres innervated by a single motor neon , smallest functional unit able ton produce force
228
types of motor unit?
slow (I)
fast fatigue resistant (IIA)
fast fatiguable (IIB)
(cell bodies, dendritic trees, conduction velocity, thickness)
229
how are the motor unit types classified?
amount of tension
fatiguability
speed of contraction
230
how is muscle force regulated?
recruitment - size principle, smaller units recruited first, allows fine control
rate coding - sloe units with lower frequencies recruited first
231
what are neurotrophic factors?
growth factor
prevent neuronal death
promote neuronal growth after injury
232
what do motor unit characteristics depend on? how is it known?
on the nerve fibres that innervate them
| cross innervation → muscle fibres changes characteristics
233
when do fibres Tina`ge from IIB to IIa?
after training
234
when do fibres change from I to II?
severe deconditioning /spinal coed injury
| microgravity
235
why do contraction times get slower with age?
loss of type I and II fibres but II lost in greater proportion
236
what manoeuvre can be used to make reflexes larger?
jendrassik → reduces amount of inhibition CNS exerts on reflexes
237
what happens in decerebration? re reflexes
reveals excitatory control from supraspinal areas (loss of inhibitory control) → over active/tonic stretch reflex → rigidity and spasticity
238
what is the positive babinski sign?
toes curl upwards (should be downwards)
this is normal in babies
UMN lesion
239
what is MS?
autoimmune disorder → loss of myelin from CNS neurons
240
symptoms of MS?
```
blurred vision
fatigue
difficulty walking
paraesthesia
muscle stifness/spasms
```
241
what is the M wave?
fast response when motor axons are activated → muscle contraction
242
what is the h reflex?
stimulus activates sensory neurons
| action potentials go nerve → spinal cord → LMN activated → motor neurons → muscle → twitch
243
what is the F wave?
large electrical stimulus - APS travel motor neurone → spinal cord (antidromic) → LMN activated → motor neurones → muscle → twitch
244
what does antidromic mean?
action potentials travel in the opposite direction to normal
| orthodromic is normal
245
what is a motor evoked potential?
seen on EMG when UMN. are activated so that action potentials travel along upper and lower motor neurons to cause muscle contraction
gives total motor conduction time (TMCT)
246
how can the motor cortex be stimulated?
transcranial magnetic stimulation
247
what is peripheral motor conduction time?
time from spinal cord to muscle along motor axon
PMCT = (M wave + F wave - 1) /2
(-1 is for time estimated for action potentials at LMN to turn around)
248
how is central motor conduction time calculated?
TMCT - PMCT
249
effects of MS on TMCT and PMCT?
MEP latency longer than usual = TMCT delayed
normal F wave latency = normal PMCT
→ problem in CNS
250
red flags for headaches?
```
thunderclap, acute onset
meningism
systemic - fever, rash, wt loss
visual loss, seizures, confusion, Horner syndrome, 3rd nerve palsy
orthostatic
strictly unilateral
```
251
presentation of a subarachnoid haemorrhage?
sudden headache
stiff neck
photophobia
252
subarachnoid haemorrhage management?
```
nimodipine and BP control
neurosurgical assessment
CT brain
lumbar puncture (RBCs and xanthochromia)
MRA
angiogram
fill aneurysm with platinum coil
```
253
what can an acute intracerbeal haemorrhage lead to?
coning due to ↑ ICP
254
what is papilloedema?
optic disc swelling due to raised ICP
255
treatment for carotid/vertebral artery dissection?
aspirin/anticoag for 6/12
256
signs & symptoms of temporal arteritis?
unilateral headache
jaw claudication
scalp tenderness
↑cRP and ESR
257
what will a biopsy show in temporal arteritis?
inflammation
| giant cells
258
treatment for temporal arteritis?
high dose steroids
| aspirin
259
what can cause blindness in temporal arteritis?
posterior cilliary artery involvement
260
what is affected in temporal arteritis?
internal elastic lamina
261
risk factors for cerebral venous thrombosis?
thrombophilia
pregnancy
Bechets
dehydration
262
viral causes of meningitis?
coxsackie
echovirus
mumps
EBV
263
bacterial causes of meningitis?
meningo/pneumoccoci
264
symptoms of meningitis?
```
fever
malaise
photophobia
neck stiffness
headache
confusion
```
265
management of meningitis?
```
treat then diagnose
Abx
blood and urine cultures
CT/MRI
lumbar puncture - ↑ WCC, ↓ glucose , antigens, cytology , culture
```
266
how will bacterial meningitis present on CT?
cerebral oedema
effacement of ventricles & sulci
inflamed meninges
267
how will sinusitis be seen on xray?
oppacifictaion of sinuses
268
symptoms of sinusitis?
malaise fever headache
loss of vocal resonance
anosmia
nasal catarrh
269
headache most often seen in obese young women?
idiopathic intracranial hypertension / pseudomotor cerebri
270
symptoms of IIH/PC?
```
headache
visual obscurations
diplopia
tinnitus
papilloedma
visual field loss
```
271
causes of IIH/PC?
hormones eg OCP
vitamin E
Abx
steroids
272
treatment for IIH/PC?
weight loss
diurteics
optic nerve sheath decompression
lumboperitoneal shunt
273
↑ ICP on CT?
effacement of ventricles and sulci with cerebral oedema
274
what can cause a low pressure headache?
CSF leak - tear in dura, traumatic, post lumbar puncture, spontaneous
275
treatment for a csf leak?
rehydration
caffeine
blood patch
276
how can a low pressure headache present on MRI?
meningeal enhancement
277
what is the chiari malformation?
brain that sits very low in skull
cerebellar tonsils descend through foramen magnum
when coughing they descend further → tug on meninges → headache
278
how can OSA lead to a headache?
↑ CO2 retained → vasodilation of blood vessels → accumulation of blood → ↑ICP
279
what can trigeminal neuralgia be a symptom of?
MS
280
what can cause trigeminal neuralgia pain?
neurovascular conflict at point of entry into pons
281
treatment for trigeminal neuralgia?
carbamazepine
lamotrigine
gabapentin
posterior fossa decompression
282
management for atypical facial pain?
tricyclics
283
risk factors for atypical facial pain?
middle aged women
depresed
anxious
284
management for post traumatic headaches?
explanation
prevent analgesic abusee
NSAIDs
tricyclics eg amitriptyline
285
commonest cause of a new onset headache in older patients?
cervical spondylosis, narrowing of joint space
286
cervical spondylosis symptoms?
```
bilateral headache
occipital pain → frontal
steady pain
no N&v
worsened by moving neck
```
287
management for cervical spondylosis?
rest, deep heat, massage
| NSAIDs
288
5 phases of migraine?
prodrome - mood changes, polyuria, cravings
aura - visual, sensory, weakness, speech
headache - w nausea and photophobia
resolution - rest and sleep
recovery - moody, food intolerance, hangover
289
what are the symptoms of migraine aura?
+ve - scintilations
| -ve - blindpsots
290
treatment for an acute migraine attcak?
NSAIDs, paracetamol, metoclopramide
Triptans with NSAIDs
nap
TMS
291
migraine prophylaxis?
```
TCAs
beta blockers
serotonin antagonists
CCBs
anticonvulsants
botox
suppress ovulation
erenumab - monoclonal antibody
```
292
management for a tension type headache?
NSAIDs
paracetamol
TCAS eg amitriptyline
293
symptoms of a cluster headache?
```
severe unilateral pain , 15-180 mins
ipsilateral conjunctival redness, lacrimation, nasal congestion, eyelid oedema
forehead/facial; sweating
miosis/ptosis
restelessness
```
294
what is a cluster headache classified as?
trigeminal autonomic cephalgia
295
treatment for acute cluster headache?
inhaled oxygen - inhibits neuronal activation in the trigeminocervical complex
sc or nasal sumatriptan
296
prevention for cluster headaches?
predinisolone
lithium
valproate
gabapentin
297
differences between migraines and cluster headaches?
```
women vs men
3-12hrs vs 45mins-3hrs
monthly vs daily
long remissions
N&V
pulsating hemicranial pain vs severe well localised unilateral pain
auras vs autonomic symptoms
lie in dark vs pacing about
```
298
structure of the BBB?
capillaries with ++ tight junctions → ↓↓ solute and fluids leakage cross capillary wall
299
symptoms of encephalitis?
flu like
pyrexia, headache
confusion, seizures, personality changes, dysarthria , weakness, loss of consciousness
300
commonest causes of encephalitis?
```
viral :
HSV
measebles
varicella
rubella
```
(mosquito, trauma, autoimmune, bacterial)
301
treatments for encephalitis?
```
anitvirals
steorids
Abx
alagesics
anticonvulsants
ventilation
```
302
commonest causes of meningitis?
```
bacterial:
meningococcla
pneumococcal
HIb
streptococcal **neonates
```
303
what are MS relapses linked to?
inflammatory activity
304
what causes inflammation in MS?
perivascular immune celll infiltration (CD3 T and CD20 B cells)
305
what is myelitis?
infection of the spinal cord (encephamyelitis if brain too)
