Term
| Describe Weber syndrome (midbrain stroke), what's affected and what it causes |
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Definition
MIDBRAIN BASIS
-Cerebral peduncle: Contralateral hemiparesis
-Fascicles of CN III: Ipsilateral CN III palsy
-CN III: Impaired ipsilateral pupillary reflex and dilated pupil |
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Term
Describe Benedikt syndrome (midbrain stroke)
- structures involved and result |
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Definition
Midbrain TEGMENTUM AND BASIS
-CN III fascicles: CN III palsy usually with dilated pupil
-Red nucleus, subthalamic nucleus: Contralateral involuntary movements |
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Term
| Describe Claude syndrome (midbrain stroke), structures involved and result |
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Definition
Midbrain tegmentum – DORSAL
-CN III fascicles: CN III palsy
- Dentatothalamic fibers within the superior cerebellar peduncle: Contralateral hemiataxia and dysmetria (you don’t see this in the Benedikt syndrome because you are weak because you hit the peduncle)
- Red nucleus: Contralateral rubral tremor |
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Term
| Describe cavernous sinus syndrome and what structures are affected |
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Definition
Ophthalmoplegia, horner's, proptosis, decreased sensation in V1 and V2
CN III, IV, V1, V2, VI and ICA |
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Term
| CNs affected in Jugular foramen syndrome |
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Definition
CN IX, X, XI
hoarse, weak shoulder, decreased sensation posterior 1/3 tongue |
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Term
| Describe carotid sheath syndrome and what structures are involved |
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Definition
Hoarse and honer's
CN XII, sympathetics to eye, ICA and jugular |
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Term
| Describe orbital apex syndrome and what is involved |
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Definition
Mass lesion near apex of eye causes ophthalmoplegia, V1 sensory loss, vision loss
Affects CN II, III, IV, V1, and VI |
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Term
| What bony structures does the ICA go through to enter the skull? |
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Definition
carotid foramen/canal> foramen lacerum
also later is in the cavernous sinus |
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Term
What does orexin do?
Where is it produced?
What inhibits it? |
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Definition
Orexin (hypocretin) promotes wakefulness and is produced in the posterior lateral hypothalamus.
It is inhibited by GABA and galanin from the VLPO (Ventrolateral preoptic area) of the anterior hypothalamus to promote sleep. |
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Term
| Describe the circuitry of REM sleep that causes the awake EEG pattern and the circuitry that reduces muscle tone |
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Definition
During REM sleep GABA from the pontine REM-on-cells and from the VLPO inhibit release of adrenaline (locus ceruleus) and serotonin (raphe nuclei), which removes inhibition of cholinergic cells and contributes to increased cholinergic inputs to the thalamus (leading to awake appearing EEG during REM sleep).
> These cholinergic neurons also activate other REM-on cells in the pons which reduce muscle tone during REM sleep, using glycine in the medulla and spinal cord. |
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Term
| What are the three major outputs of the reticular formation (for arousal)? |
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Definition
Basal forebrain
Hypothalamus
Thalamus |
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Term
| What are the 4 major inputs to the reticular formation (for arousal)? |
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Definition
Thalamic reticular nucleus
Limbic and cingulate cortex
Sensory from body
From fronto-perietal association cortex |
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Term
| What are the 4 main regions of the brain that produce acetylcholine? |
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Definition
-Medial septal nucleus (projects to hipoccampus)
-Nucleus basalis of Meunert (projects to cortex)
- Laterodorsal tegmental nucleus and peduncopontine nucleus |
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Term
| What two locations in the brain produce dopamine? |
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Definition
Substantia nigra pars compacta
Ventral tegmental area |
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Term
| What are the 3 potential projections of dopamine in the brain and what does each do? |
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Definition
Mesostriatal pathway: to striatum (caudate and putamen) to promote movement in basal ganglia
Mesolimbic: involved in reward circuitry
Mesocortical: to prefrontal cortex to promote working memory, movement initiation (in abulia) |
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Term
| Where are the respiratory centers in the brainstem? |
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Definition
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Term
| What artery supplies the inferior cerebellum and lateral medulla? Where does it come from? |
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Definition
| The PICA (first branch off the basilar artery) |
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Term
| What artery supplies the medial cerebellum? What else does it supply? |
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Definition
the AICA (second branch off of the basilar)
also supplies the internal auditory artery |
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Term
| What arteries supply the pons? |
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Definition
Basilar perforators:
Short circumferential arteries supply lateral pons
Paramedian penetrating arteries supply the deep pons (along the ventricle) |
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Term
What is affected in Foville's syndrome (stroke)?
- Where
- Tracts affected
- Clinical features |
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Definition
- stroke of medial pontine base and tegmentum
- Corticospinal and corticobulbar tracts + facial colliculus
- whole face weakness, contralateral arm and leg weakness, ipsilateral horizontal gaze palsy
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Term
Pontine wrong-way eyes
- Where
- Structures involved
- Clinical features |
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Definition
- stroke of medial pontine base and tegmentum
- Corticospinal and corticobulbar tracts + abducens nucleus or PPRF
- contralateral face weakness, arm and leg weakness, ipsilateral horizontal gaze palsy |
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Term
Millard-Gubler syndrome
- Where
- Structures involved
- Clinical features |
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Definition
- stroke of medial pontine base and tegmentum
- Corticospinal and corticobulbar tracts + facial colliculus
- whole face weakness, contralateral arm and leg weakness, ipsilateral face weakness |
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Term
Describe AICA syndrome
-Where
-Structures involved and clinical features |
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Definition
In the lateral caudal pons
Middle cerebellar peduncle: ipsilateral ataxia
Vestibular nuclei: vertigo and nystagmus
Trigeminal nucleus: decreased ipsilateral pain and temp sensation
Spinothalamic tract: decreased contralateral pain and temp sensation
Descending sympathetics: ipsilateral horner's |
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Term
| Where is norepinephrine produced in the brain? (2) |
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Definition
| Pons: locus ceruleus and lateral tegmental area |
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Term
| Where is serotonin produced in the brain? (3) |
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Definition
| Midbrain, pons, and medulla raphe nuclei |
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Term
| Where is histamine produced in the brain? (2) |
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Definition
Hypothalamus: tubomammillary nucleus
Midbrain: reticular formation |
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Term
Describe Medial medulla syndrome (stroke)
- Vascular supply
- Structures affected and clinical features |
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Definition
Stroke from the paramedian branches of vertebral and anterior spinal arteries
Pyramidal tract: contralateral arm and leg weakness
Medial lemniscus: contralateral decreased position and vibration sense
Hypoglossal nucles: Ipsilateral tongue weakness |
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