Neuro Flashcards
(228 cards)
1
Q
Where does cauda equina start?
A
T12/L1
2
Q
Is the cauda equina part of SNS or PNS?
A
PNS
3
Q
Condition where posterior neuropore of neural tube fails to close?
A
Rachischisis
4
Q
Does spina bifida have neurological deficits?
A
Yes! But no cognitive deficit
5
Q
Causes of hydrocephalus?
A
Spina bifida, cerebral aqueduct stenosis
6
Q
Types of spina bifida?
A
Occulta, meningocele (arachnoid only), myelomeningocele (arachnoid and neural tissue)
7
Q
How can we detect neural tube defects prenatally?
A
Serum alpha fetoprotein
8
Q
What is an arnold-chiari malformation?
A
Cerebellum sits in foramen magnum, hydrocephalus results. Type II chiari malformations due to myelomeningocele.
9
Q
Why do we have a cauda equina?
A
Because after 3mo’s the vertebral column grows faster than the cord
10
Q
What do neural crest cells become?
A
Dorsal root ganglions, bones of face and skull, melanocytes, adrenal medulla, schwann cells
11
Q
Why are neural crest cells so vulnerable to teratogens?
A
They have a very complex migratory pattern
12
Q
Name two genetic diseases associated with neural crest cells?
A
Hirschprung’s disease- nerves missing from GI so constipation
DiGeorge- problem in neural crest migration e.g. leading to abnormal facies, thyroid problems, cardiac defects
13
Q
Where do somatic reflex arcs synapse?
A
ventral horn of spinal cord
14
Q
What is the jendrassik maneouvre?
A
clench teeth and lock hands and pull, easier to elicit reflexes
15
Q
What do you use gadolinium for?
A
Can reveal vascular tumours or meningiomas on MRIs because it doesn’t cross the BBB normally and will reveal if the BBB has been breached
16
Q
Name the three types of glia
A
Astrocytes, oligodendrocytes, microglia
17
Q
What do astrocytes do?
A
Provide lactate (neurons can’t store glycogen so need lactate for citric acid cycle for ATP), re-uptake of neurotransmitters and to mop up K+
18
Q
Astrocytes and oligodendrocytes are from ____, microglia are from ____
A
astro and oligo from ectoderm, microglia from mesoderm
19
Q
Name layers of the BBB
A
Lumen of capillary, basement membrane and endothelial cells surround it, then pericytes are around endothelial cells and can make capillaries contract, then foot processes of astrocytes
20
Q
Can T cells enter the CNS?
A
Yes, but then something in the brain inhibits a pro-inflam response
21
Q
What channel opens in neurons that triggers release of presynaptic neurotransmitter?
A
Calcium channels
22
Q
Name inhibitory neurotransmitters of CNS
A
Glycine, GABA
23
Q
Name mixed + and - neuroTs of CNS
A
NA, 5-HT, dopamine
24
Q
Name activatory neuroTs of CNS
A
Glutamate, ACh
25
Name amino acid neuroTs
GABA, glycine, glutamate
26
Name biogenic amine neuroTs
ACh, NA, dopamine, 5-HT
27
Location of ACh neurons
Basic ace- nucleus basalis & septal neurones
28
Location of dopamine neurons
Nigrostriatal pathway, mesolimbic, mesocortical
29
Location of NA neurons
Locus coeruleus of pons
| Medulla
30
Location of 5-HT neurons
Brainstem raphe nucleus
31
Are you aroused in this locus?
NA!
| Na is the neuroT, locus ceruleus is the place
32
What does ACh have a role in?
Arousal. In the nucleus basalis, arousal is basic
33
What are the dopamine pathways roles?
Nigrostriatal is motor control, mesolimbic/cortical are mood, arousal, reward.
34
Two neuroTs involved in patellar reflex?
Glutamate to activate effector quadriceps, glycine to inhibit hamstrings to relax them
35
What are the jobs of the cerebellar peduncles and the cerebral peduncles?
Cerebellar peduncles attach cerebellum to brainstem and cerebral peduncles (crux cerebri) attach cerebrum to brainstem
36
Where is the tectum? (and what does it consist of)
Dorsal part of midbrain. The superior and inferior colliculi together make the tectum
37
What do the medullary pyramids do?
Descending motor pathways
38
How is glycine involved in sleep?
Glycine in the basal ganglia paralyses LMNs in sleep
39
What do arachnoid granulations do?
Transfer CSF from subarachnoid space into dural venous sinuses
40
What do the neural tube and the neural canal become?
The neural tube becomes the tissue of the CNS and the neural canal becomes the ventricular system
41
What is white matter?
Axons and glial cells
42
What structures is ventricle IV associated with?
Pons, medulla, cerebellum
43
Where are ventral and dorsal root cell bodies found, respectively?
Ventral root cell bodies are in the gray matter of the spinal cord and dorsal root cell bodies are in ganglia
44
What meningeal layers cover the spinal cord?
Pia, arachnoid and dura, and the arachnoid and dura are very tightly connected together and CSF circulates in subarachnoid space
45
Where does C8 emerge?
Between vertebrae C7 and T1
46
What is the conus medullaris?
Terminal end of the spinal cord at L1/2. Cauda equina is below (which is dorsal and ventral roots below the conus medularis)
47
What's a safe level for LP?
L3/4. Go lower in babies because their conus medullaris is at L3.
48
Which modalities travel in spinothalamic?
Temperature, pain, pressure (crude touch)
49
Which modalities travel in dorsal column?
Two-point discrimination, fine touch, vibration, propioception
50
How does the acuity of a sensory neuron relate to the size of its receptive field?
Big receptive field = lower acuity, small receptive field = higher acuity
51
Does the brain think in terms of dermatomes?
No, it converts them to the homunculus
52
What nerve symptoms can a patient with vitamin B12 deficiency (e.g. due to pernicious anemia where intrinsic factor not made)?
Glossitis, parasthesia, muscle weakness (due to denervation of dorsal column and sometimes lateral columns)
53
Hirschsprung’s disease?
Absence of ganglions in GI causing constipation and need for surgery
54
Where would vibration from the leg travel (in which side) and where would it synapse (in which nuclei)
Enters the dorsal column medially and synapses in the gracile nucleus of the medulla
55
Where would vibration from the arm travel (in which side) and where would it synapse (in which nuclei)
In the lateral side of the dorsal column, synapsing in the cuneate nucleus of the medulla
56
Where are upper and lower body in the spinothalamic tract
Upper is deep
| Lower is superficial
57
What are c and a fibres
C are pain
| A are mechanosensory and can activate inhibitory interneurones to inhibit pain eg if rubbing
58
Where do DC and ST fibres decussate
DC decussates in medulla (gracile and cuneate nuclei)
| ST decussates in dorsal horn of spinal cord
59
Where do DC and ST fibres swap lower and upper fibre positions to be in the right position for the homunculus
DC lower fibres start medially, after the medulla they decussate and swap sides so still medial on their contralateral side
ST lower fibres synapse in dorsal horn and decussate, go to contralateral side in same positions so need a swap over in the tertiary neurones in cortex
60
Describe Brown-Sequard
When one half of the spinal cord is damaged, you get DC (fine touch, 2 point, vibration, propio) damage on ipsilateral side because it hasn't decussated yet and ST damage (crude touch, pain, temp) on ipsilateral side because its already decussated
61
What nerve symptoms might vegans present with?
Parasthesia and muscle weakness- can cause a B12 deficiency which denervates particularly posterior and sometimes lateral columns. Might also have a smooth tongue!
62
What's syringomyelia?
Cyst in the spinal cord that expands over time, may be caused by a chiari malformation
63
What is lateral inhibition and which cells are responsible for it?
When one neuron becomes excited it reduces the activity of its neighbours. Horizontal cells do this.
64
What cells are present at the fovea?
Cone cells in high amounts
No ganglions
No bipolar cells
65
Describe the pathway of light information to the optic nerve
Through cornea, through lens, through the neural layer of the retina (ganglions then bipolar cells then photoreceptors) then the pigmented layer of the retina and then choroid
66
Describe the impulse pathway in the eye
Photoreceptors --> bipolar cells --> ganglions --> optic nerve
67
What technique do you use to look at the retina e.g. for retinal detachment
Optical coherence tomography
68
The right visual field is received by which orbit
The left side of the orbit
69
A lesion in the right optic nerve produces what deficit
Monocular vision loss
70
A lesion in the optic chiasm produces what deficit
Bitemporal hemianopia
71
A lesion in the right optic tract produces what deficit
Contralateral homonymous hemianopia (ie right orbit of both eyes, left visual field of both eyes)
72
A lesion in the right superior/parietal fibres produces what deficit
Contralateral inferior quandrantonopia
73
A lesion in the inferior/temporal fibres produces what deficit
Contralateral superior quandrantonopia
74
A posterior cerebral artery stroke produces what deficit
Contralateral homonymous hemianopia with macula sparing
75
What results in macula sparing
Posterior cerebral artery supplies most of occipital lobe where PVC is but the MIDDLE cerebral artery supplies the occipital pole which supplies the macula
76
Describe the pathway for the pupillary reflex
Light enters left eye, left optic nerve, optic chiasm, optic tract, splits to enter pretectal area, projects onto both EDW nuclei for consensual, ciliary ganglion, pupil constricts via sphincter pupillae
77
Describe the accomodation reflex in terms of contracting the ciliary muscle (and when you'd do this)
Optic nerve, optic chiasm, optic tract, LGN, pre-tectal area, EDW, CN III to ciliary ganglion, contracts ciliary muscle
If ciliary muscle is contracted, suspensory ligaments are slack, so lens is fat and the object is near
78
What are the three Cs of accomodation
Pupillary constriction, convergence (medial rectus) and convexity of lens
79
Why do you get glare with cataracts
Because of the contrast of light levels getting through cloudy patches vs clear patches
80
What is internuclear opthalmoplegia
Damage to the medial fasiculus (white matter tract) that is responsible for adducting affected eye when other eye moves laterally. Communicates between CNs III, IV, and VI and coordinates eye movements: responsible for optokinetic, saccadic and vestibulocular movements
81
What are optokinetic, saccadic and vestibulocular movements
Optokinetic- fixation on objects moving relative to head
Saccadic- quick eye movements
Vestibulocular- movement of eyes in relation to movement of head
82
In what disease could you get internuclear opthalmoplegia
MS- involves demyelination of white matter structures such as the medial fasiculus
83
Considering which structures are nearby, in a patient with a tumour in the cerebral aqueduct of the midbrain what eye symptoms could result?
Close to EDW- this is where accomodation occurs so eyes won't accomodate. Also where it would signal to constrict the pupil so that won't happen in the same eye
The oculomotor nucleus is also close- down and out eye
84
```
Describe functions of the midbrain "mickey mouse":
Ears
Eyes
Tears
Nose
Nose hairs
Mouth
Lips
Double chin
```
Ears- cerebral peduncles so descending motor tracts
Eyes- red nuclei, motor function
Tears- medial lemniscus. Part of DC, ascending sensory tract on its way to the thalamus
Nose- CN III and EDW
Nose hairs- CN III fibres
Mouth- cerebral aqueduct
Lips- periaqueductal grey matter
Double chin- superior colliculus. Does reflex responses of visual system eg look at lightning. Inferior colliculus at lower levels does reflexes to auditory stimuli
85
Which two paired arteries supply the brain?
Internal carotid and vertebral arteries
86
Name the branches of the internal carotid that form the circle of willis
(Opthalmic artery), posterior communicating, anterior cerebral, and then continues as the middle cerebral
87
How do the paired vertebral arteries contribute to the circle of willis?
Give off posterior inferior cerebellar artery, combine to form basilar artery, pontine arteries, anterior inferior cerebellar artery, superior cerebellar artery, end by birfurcating as the posterior cerebral artery
88
Where do the anterior, middle, and posterior cerebral arteries supply?
Anterior is misleading because its mostly medial at the front
Middle is lateral frontal and parietal, and superior temporal
Posterior is occipital and inferior temporal
89
What important branch of the middle cerebral artery is prone to emboli
Lenticulostriate branches- role in motor function
90
What do the pontine arteries of the basilar artery do and what condition results if there is a problem
Supply the pons
| Locked in syndrome
91
Which vessels supply the cerebellum and where else do they help supply?
Superior cerebellum
Anterior inferior
Posterior inferior
Also supply the brainstem on their way down
92
Lenticulostriate vessels supply the...
Internal capsule
93
Which neurones are involved in the motor pathway? (always descending)
UMN and LMN
94
Where are UMNs and LMNs located
UMN are exclusively CNS, LMN has cell body in CNS but axon goes into PNS
95
Where are the cell bodies of LMNs located
Either in the ventral horn of the spinal cord or the motor nuclei in the brainstem
96
Describe the patellar reflex
Muscle spindle detects stretch in patellar tendon
Afferent fibre along L3 spinal nerve travels to ventral horn of spinal cord, where it synapses with a LMN that will send an efferent signal to contract the quads
The sensory neurone also sends a signal to an inhibitory interneurone at L5 which acts to inhibit the LMN for the hamstrings, relaxing them to allow contraction of the quads
This is called reciprocal inhibition
97
What is reciprocal inhibition
In reflexes you inhibit one action to allow for activation of the other e.g. in patellar reflex the hamstrings are inhibited
98
What is the purpose of tendon reflexes
Postural correction- e.g. if get blown by wind it will detect the extending and act to contract to bring you back to normal
99
What is the babinski reflex
If stimulated on lateral border of foot this elicits plantarflexion in normal adults. In babies and people with UMN damage this causes plantarextension
100
Name UMN damage signs
Hyperreflexia (because overall effect of UMNs on LMNs is inhbitiory)
Extensor Babinski
Hypertonia
Weakness
101
Name LMN damage signs
```
Areflexia
Hypotonia
Weakness
Wasting
Fasiculation
```
102
What is spinal shock
UMN signs (except weakness) take days-weeks to develop so UMN damage initially presents as LMN signs. This is because LMNs are initially depressed following UMN damage but later become excited
103
Where are UMN cell bodies found
Precentral gyrus only
104
Describe the journey from the cell body of an UMN for the lower limb to its target
```
Starts in medial precentral gyrus
Through corona radiata
Internal capsule
Enters midbrain via cerebral peduncles
Enters medulla via medullary pyramids
Decussates in the medulla
On other side is part of the lateral corticospinal tract in the lateral funiculus
Descends down spinal cord to synapse with LMN in ventral horn
```
105
What is the lateral corticospinal tract
Part of the route of an UMN after it decussates in the medulla- it is responsible for fine, dextrous movements in the extremities e.g. hands
106
How is the route of an UMN supplying the face different to other UMNs
It starts more laterally in the precentral gyrus, as normal descends through corona radiata and internal capsule but instead of decussating in the medulla it leaves the internal capsule to go in the corticobulbar tract
107
Tell me about the facial motor nuclei and how it affects UMN lesions
So the facial motor nuclei to the upper face has bilateral UMN innervation but the lower face is unilateral. This means that if there is a lesion of the left UMN, this results in right lower face paralysis but not right upper face paralysis (because still receiving innervation from other side)
= UMN lesion is forehead sparing
108
How will facial nerve lesions present compared to UMN lesions supplying face?
Facial nerve lesion = complete unilateral paralysis
| UMN lesion supplying face = forehead sparing unilateral lower face paralysis
109
What are the vestibulospinal and reticulospinal tracts?
Vestibulospinal- connects semicircular canals to spinal cord so allows postural changes with movement info
Reticulospinal- connects reticular formation to spinal cord so inhibitory pathways in sleep go through here
110
How does the cerebellum connect with the brainstem and name the different parts of this structure
Cerebellar peduncles
Superior c.p. connects to midbrain
Middle c.p. connects to pons
Inferior c.p. connects to medulla
111
Via what structure does the cerebellum communicate with the cortex
Thalamus
112
Describe the structure of the cerebellum and what the different parts control
Vermis in the midline controls the trunk
| The lateral hemispheres control the limbs
113
Tracts in the cerebellum are ipsi/contra lateral?
Ipsilateral
114
What is ataxia?
Lack of coordination
115
What kind of symptoms could a vermis lesion cause
Pressing on 4th ventricle --> hydrocephalus
Truncal ataxia
Abnormal gait
116
Describe symptoms of cerebellar disease
```
DANISH
Dysdiadochokinesis
Ataxia (e.g. ataxic gait)
Nystagmus
Intention tremor
Slurred speech
Hypotonia
```
117
What is the basal ganglia
```
Caudate nucleus
Putamen
Globus pallidus (interna and externa)
Thalamus
Substantia nigra (pars compacta and pars reticularis)
```
118
What is the striatum
Putamen + caudate nucleus
119
What is the lentiform nucleus
Putamen + globus pallidus
120
Tell me about the substantia nigra
The pars compacta is more dorsal and has dopamingergic neurons- double D.
The pars reticularis is ventral
121
Is dopamine excitatory or inhibitory?
Can be either!
122
How do the direct and indirect pathways of the basal ganglia affect the thalamus with and without presence of dopamine?
Direct is excitatory to the thalamus and then more excitatory with dopamine
Indirect is inhibitory to the thalamus and then excitatory with dopamine
123
What sort of symptoms do basal ganglia disorders cause
Dyskinesis, abnormal motor control, altered posture, altered muscle tone
124
Define Parkinson's disease
Chronic progressive movement disorder with unilateral bradykinesia, hypertonicity and resting tremor. Also micrographia, shuffling gait (risk of falls), depression, reduced facial expression, dementia, hypophonia.
125
How does Parkinson's disease affect the basal ganglia pathways
Direct without dopamine is overall stimulatory (but less so)
| Indirect without dopamine is inhibitory
126
Define Huntingdon's disease
AD progressive neurodegenerative disorder, onset 30-50yrs. Chorea (abnormal jerky movements), dystonia, incoordination, cognitive decline, behavioural difficulties, abnormal gait. Occurs due to loss of GABAnergic neurones in the striatum (putamen + caudate nucleus)
127
What is chorea
Abnormal jerky movements, occurs with Huntingdon's disease
128
How does Huntingdon's cause its effects
Loss of gabanergic neurons in the striatum (caudate nucleus + putamen)
129
Where is the subthalamic nucleus?
Just medial to the substantia nigra
130
What is hemiballismus?
Dysfunction in contralateral subthalamic nucleus (structure just medial to substantia nigra). Causes large amplitude unilateral abnormal movement- sudden intense flailing motion. Often secondary to subcortical lacuna strokes
131
What can a subcortical lacuna stroke cause?
Hemiballismus
132
Following destruction of C3 and C4 spinal cord, at what levels would UMN and LMN signs appear?
C3 and C4 have had their LMNs destroyed so will have LMN signs (hyporeflexia, hypotonia) but below this LMNs are fine but have lost connections with UMNs so will have UMN signs (hyperreflexia, hypertonia), extensor plantar reflex
133
How will motor signs be different if spinal cord damage is blunt or sharp?
If it is blunt it will destroy the LMNs in those segments so will get LMN signs there and UMN signs below
If it is sharp the LMNs themselves will be intact so just initial spinal shock (looks like LMN) and then UMN signs
134
What is motor neurone disease?
Group of diseases with differential LMN and UMN involvement. ALS is both LMN and UMN, SMA is pure LMN
135
What does this suggest: 73yo F left hand tremor, bilateral hypertonia (but more on L side), shuffling gait, paucity of movement
Parkinson's- Suggests neurodegeneration in SNc (R side especially).
136
Where is this lesion: 29yo F unsteady gait, vertigo, 3mo progression, impaired coordination (R side more), nystagmus, slurred speech
Right cerebellar hemisphere
137
If having cerebellar surgery, what could you damage?
Brainstem, anything in jugular foramen (IX,X,XI), IAM (VII,VIII), vertebral arteries, occipital lobe
138
Define dermatome and myotome
```
Dermatome = area of skin supplied by a single spinal nerve
Myotome = muscles supplied by a single ventral root
```
139
What pattern is information arranged in the cord versus the brain, and where changes this organisation?
Spinal cord is dermatomal
Brain is homuncular
Thalamus changes the code
140
What structure does the thalamus squash?
The third ventricle
141
What colours are grey matter, white matter and CSF on a CT
CSF black
Grey matter white
White matter dark
142
Name the parts of the internal capsule and where it runs between
Anterior limb, genu, posterior limb
| Runs between cortex-thalamus
143
Which part of brain do these go to:
Left visual fields -->
Superior visual fields -->
Inferior visual fields -->
Left to right hemisphere
Superior to inferior radiations
Inferior to superior radiations
144
If the lateral ventricles inflated, what structures could they damage?
Corpus callosum, caudate nucleus, corona radiata, cortex
145
If the third ventricle inflated, what could it damage?
Thalamus
146
What is the medial lemniscus?
Part of the dorsal column between the medulla where the fibres decussate and the thalamus
147
If the cerebral aqueduct expanded, what could it damage?
Passes through midbrain so could damage CN III motor nuclei, EDW, medial lemniscus, cerebral peduncles
148
Which structures are immediately above and below the lateral ventricles?
Corpus callosum is above (with cingulate gyrus above that)
| Fornix is below
149
The internal capsule is between...
The globus pallidus interna and the thalamus
150
Which structures are involved in motor planning
Prefrontal cortex thinks of movement it wants to do
Basal ganglia chooses a set of movements
Cerebellum looks at current position of limbs to decide which sequence the movements should be carried out in
151
Where do inputs to the cortex come from?
1. Other cortical neurones
| 2. The thalamus
152
What is the major output of the cortex?
Pyramidal cells (excitatory neurones, particularly prominent in motor and premotor areas. UMNs are a type of pyramidal cells)
153
What functions does the frontal lobe have
Judgment, social and sexual behaviour, personality, Broca's area (motor component of speech), precentral gyrus so motor centre (inc. continence), memory, problem solving
154
What functions does the parietal lobe have
Postcentral area so sensory centre, Wernicke's area (comprehension of speech), calculation, writing, understanding body image, awareness of external environment, superior optic radiations
155
Temporal lobe functions
Primary auditory cortex
Olfactory cortex
Inferior optic radiations pass through
Memory and emotion
156
Tell me about cerebral lateralisation
Left hemisphere is normally language functions and calculation/logic
Right is normally body image, emotion, music, visuospatial awareness
157
Why might you cut someone's corpus callosum?
In epilepsy to prevent activity spreading from one hemisphere to the other
158
Where are Broca's and Wernicke's areas located?
Broca lateral inferior frontal (near motor cortex)
| Wernicke inferior parietal (near auditory cortex)
159
How are Broca's and Wernicke's connected?
Arcuate fasciculus
160
What are Broca's and Wernicke's aphasia?
Broca's- can understand speech but has difficulty speaking
| Wernicke's- no problem speaking but problem understanding (fluent speech that doesn't make sense)
161
How do you speak a written word?
Visual cortex in the occipital lobe receives visual information → Wernicke’s area which converts visual signals into words → via arcuate fasiculus → Broca’s area makes motor plan → motor cortex in precentral gyrus to move the mouth
162
How do you speak a thought?
Thoughts could come from anywhere in the cortex → Wernicke’s area comprehends these and turns into words → arcuate fasiculus → Broca’s area makes motor plan → motor cortex in precentral gyrus moves the mouth
163
Name the two types of memory and where they are stored
Declarative (explicit facts)
Non-declarative (implicit, motor skills, emotion)
Declarative stored across cerebral cortex, non-declarative stored in cerebellum
164
Name a part of the brain that's important for consolidating declarative memories
Hippocampus- strengthens association between neurones by making them release more neuroTs, more post-synaptic Rs
165
Define arousal
Being directed towards a goal or avoiding something noxious
166
Define consciousness
Being aware of internal and external states
167
What are the two ingredients for consciousness
Cerebral cortex and reticular formation
168
What is the reticular formation
Important for consciousness, group of interneurones in the brainstem that communicates with the cortex and receives input from cortex and somatosensory system
169
What are the three excitatory outputs of the reticular formation
- -> basal forebrain nuclei --> ACh to excite cortex
- -> hypothalamus --> histamine to excite cortex
- -> thalamus --> glutamate to excite cortex
170
Why can antihistamines and anticholinergics make you drowsy?
Outputs from the reticular formation:
- basal forebrain nuclei use ACh to excite cortex
- hypothalamus uses histamine to excite cortex
171
What are the ascending fibres called that go between the reticular formation and its relay stations?
Reticular activating system
172
What three things does the GCS assess?
eye opening, motor response, verbal response
173
Name 2 ways to assess consciousness
GCS (scale)
| EEG
174
What do cortical neurones have a tendency to do?
Synchronise! This is what happens in sleep
175
Describe a normal sleep
5-6 cycles of sleep, between REM-stage 1-stage 4- REM
176
What are alpha and beta waves
Beta waves are eyes open or REM sleep, 50Hz frequency
| Alpha waves are eyes closed- less inputs to brain so more synchrony, waves slow down 10Hz
177
What is stage 1 sleep
Background of alpha waves (10Hz) with some theta waves (5Hz)
178
What is stage 2/3 sleep
Background of theta waves (5Hz) with final death throws called sleep spindles and big broad K complexes
179
What is stage 4 sleep
Dominated by K complexes which here are called delta waves (1Hz)
180
What area is responsible for REM sleep?
Pons
181
Why is it hard to wake people up in REM sleep?
The thalamus is strongly inhibited so its hard to get inputs up to the cortex
182
Why do you get floppy limbs in sleep?
The RF sends glycinergic projections down to LMNs to inhibit them
183
Why do you get nocturnal bruxism?
Teeth grinding at night even though limbs are floppy is because teeth grinding is controlled by cranial nerves which reside in the brainstem, rather than LMNs in the spinal cord (which are inhibited by glycine)
184
What other things happen in REM?
Consolidation of knowledge and autonomic effects such as penile erection
185
Compare and contrast coma and persistent vegetative state
Coma- widespread cortical and brainstem damage, no sleep-wake cycle, unresponsive to stimuli
Persistent vegetative state- sleep-wake cycle detectable, cortex is damaged but RF is relatively spared, can respond to stimuli via brainstem reflexes, some spontaneous eye opening
186
What is locked in syndrome
Fully conscious but no control of body (cortex is fine but pons is not)- caused by damage to pontine artery
187
Name ways in which infection could reach brain
In the blood e.g. meningitis
Direct spread e.g. basal skull fracture, infection in danger triangle
Iatrogenic e.g. LP
188
Define meningitis
Inflammation of the leptomeninges (arachnoid and pia), with or without septicaemia
189
Name causative organisms of meningitis at different ages
Babies: e.coli, listeria monocytogenes
2-5: Haemophilus influenza type B (hence vaccine happens then)
5-30: neisseria meningitidis
190
Define SIRS, sepsis, severe sepsis, septic shock
SIRS is resp rate over 20, temp over 38 or less than 36
Sepsis is SIRS with infection confirmed
Severe sepsis is sepsis with organ failure, hypotension, hypoperfusion
Septic shock is when hypotension won't respond to fluids
191
Typically encephalitis (i.e. infecting neurones) is what type of organism? Give examples
Viral
| e.g. rabies affects brainstem, herpes affects temporal lobe
192
Viral replication within neurones (as in encephalitis) produces which microscopic pathology
Inclusion bodies (look like owl's eyes)
193
How does encephalitis present and how should you treat
Less acutely than meningitis with headaches, vomiting, photophobia. Manage supportively
194
Define dementia
Global loss of intellect, reason and personality without damage to consciousness. Most common cause is Alzheimer's (also Lewy body, vascular, Picks disease)
195
What is Alzheimer's disease
Most common cause of dementia. An exaggerated ageing process with senile atrophy (loss of cortical neurones), wider sulci and narrower gyri
Tau proteins become hyperphosphorylated and clumps --> neurofibrillary tangles
Amyloid proteins abnormal --> amyloid plaques
196
Name a cause of familial Alzheimer's disease and why it causes this
Down's syndrome (30-40yo). Chromosome 21 encodes for amyloid precursor protein, presinilin genes 1 and 2 (which break amyloid down). So problems with these --> abnormal amyloid --> amyloid plaques
197
What is ICP normally, on coughing/straining, and what level must it be lower than
Normally 10mmHg
On coughing 20mmHg
Must be lower than the systolic BP otherwise blood can't get here
198
Up to what level can vascular mechanisms keep ICP compensated? Beyond this what happened?
Up to 60mmHg
| Above this you get hypertension so that the BP is higher than the ICP
199
What is Cushing's reflex?
Hypertension (need BP to be higher than ICP to maintain perfusion)
Bradykinesia (aortic arch baroreceptors trigger vagus)
Low resp rate (ischaemia to medulla respiratory centres)
200
Name three types of brain herniation
Subfalcine- cingulate gyrus pushed under falx cerebrum (may be asymptomatic, haemorrhage, ischaemia, contralateral leg weakness)
Uncal/tentorial- uncus goes through tentorium (presses on midbrain, CN III, cerebral peduncle so contra leg weakness)
Cerebellar- "coning", cerebellum into foramen magnum (reduced consciousness, resp and heart dysfunction)
201
Name benign and malignant CNS tumours
Benign- meningioma
| Malignant- most common is mets to the brain (lung, colon). Also astrocytomas
202
Risk factors for stroke
HTN, hyperlipidemia, DM
203
Name categories of stroke
Ischaemic (80%)- normally from embolism
| Haemorrhagic (20%)
204
What is a subarachnoid haemorrhage
Rupture of a berry aneurysm (abnormal outpouching of vessel). Risks are HTN, male, PCKD. Sudden thunderclap headache
205
Define dementia
Progressive decline in cognitive function leading to global impairment of memory, intellect and personality that affects ability to cope with daily living
206
Name reversible causes of dementia
Depression, trauma, vitamin deficiency, alcohol, thyroid disorders
207
Describe possible presenting symptoms of dementia
altered personality, wandering, anomic aphasia (can't retrieve word they want), dysphagia, reduction in food intake, apraxia
208
What should you do if patient presents with possible dementia
```
MMSE (mini mental state exam) to ascertain baseline
Check for reversible causes of dementia
Full neuro exam
CT/MRI
Memory clinic refer
```
209
Describe delirium
Acute confused state that has presented suddenly e.g. fall, severe pain, constipation, UTI. Signs are fluctuating mental status, fluctuating agitated/very quiet, inattention, disorganised thinking
210
What score do you test for dementia and delirium
```
Dementia MMSE
Delirium CAM (confusion assessment method)
```
211
Describe the progression of dementia from AD, Lewy body, and vascular
AD- slope
Vascular- step wise
Lewy body- loopy up and down
212
How does dementia with lewy bodies link to Parkinson's?
Parkinson's is Lewy bodies in the substantia nigra
In dementia w LB they are in the SN and the cortex, presenting with bradykinesia and resting tremor PLUS visual hallucinations, cognitive impairment, frequent falls
213
Describe management of dementia
Meds: can give acetylcholinerase for mild/mod AD but doesn't work in most
Family: discuss care, mental capacity to make decisions now and in the future
Memory aids and therapies (pets, babies)
214
Define seizure
A sudden irregular discharge of electrical activity in the brain causing symptoms e.g. sensory disturbance, convulsions
215
What is status epilepticus
Continuous epileptic seizures without recovery of consciousness in between, a medical emergency, may become cyanotic
216
What are the first and second most common partial seizures and what makes them more likely to occur
First- temporal lobe epilepsy (often comes with auras). More common in 1st/2nd decade following fever or early brain injury
Second most common parietal lobe
217
Name the five types of generalised seizures
```
Affect whole brain
Absence (daydreaming)
Myoclonic (break muscle jerking)
Tonic (increased tone)
Atonic (drop to floor)
Tonic-clonic (increased tone then convulsions)
```
218
Give causes of epilepsy
```
Vascular- stroke, TIA
Infection- TB, meningitis
Trauma- intracerebral haemorrhage
Autoimmune- SLE
Metabolic- hypoxia, hypoglycaemia, thyroid
Iatrogenic- drugs
Neoplastic
Congenital
```
219
Describe management of epilepsy
Acutely ABCDE and benzos (lorazepam, diazepam- GABAa agonists)
MRI for new onset seizures, EEG can support diagnosis but not diagnose
220
How does dementia most commonly result in death
Dysphagia and aspiration
221
Diagnose: patient with one sided weakness and sensory loss in limb/genitals plus urinary incontinence
ACA stroke
| UI from paracentral lobules in medial frontal and parietal
222
Diagnose: patient with one sided weakness and sensory loss in upper limb/face plus leg, contralateral hemianopia, hemispatial neglect, global aphasia,
MCA stroke
| Face too because its affected internal capsule (MCA branches lenticulostriate artery)
223
Diagnose: patient with contralateral heminanopia with macula sparing
PCA stroke
224
Diagnose: patient with DANISH symptoms and R sided oculomotor deficit and L sided weakness
Cerebellar artery stroke
| Get crossed deficits (ipsilateral CN with contralateral long nerves)
225
Diagnose: fully conscious but no motor control
Basilar artery/pontine artery stroke
226
Diagnose: blindess from a stroke
Basilar artery stroke (bilateral loss of PVC occipital lobe supply)
227
Hyperdense =, hypodense =
Hyperdense is white!
| Hypodense is black
228
Name non stroke causes of weakness/dysphagia
Hypoglycemia
Epilepsy
Intracranial tumours
Migraine
