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91

GPe vs. GPi/SNr

GPi/SNr tonically inhibits the VA/VL. GPe tonically inhibits the sub-thalamic nucleus (which activates the GPi/SNr). Globus = globally tonically active in inhibiting. Internal segment INHIBITS movt. External = EXTRA and inhibits STN, which normally inhibits GPi)

92

Chorea vs. athetosis?

Sudden jerky movts vs. slow writhing movts (esp. fingers). Both seen in basal ganglia lesions (HD).

93

Essential vs. resting vs. intention tremor?

Action tremor exacerbated by holding posture/limb vs. alleviation by movt (Parkinson's) vs. poor finger2nose (cerebellar)

94

General homunculus

Medial to lateral = Toes to hand to face to tongue and swallowing

95

Amygdala lesions

B/l - Kluver-Bucy = hyperorality, hypersexuality, disinhibied behavior. Associated with HSV-1

96

Mammillary body lesion?

B/l lesions in Wernicke-Korsakoff syndrome (confusion, opthalmoplegia, ataxia, memory, confab, personality)

97

STN lesion?

STN activates GPi to inhibit movt. So lesion = contralateral hemiballismus.

98

Hippocampus lesion?

B/l lesions lead to anterograde amnesia.

99

Central pontine myelinolysis

Massive axonal demyelination in pontine white matter 2/2 osmotic forces and edema (Na+ from low to high correction). Acute paralysis, dyarthria, dysphagia, dipolopia, LOC. (Pseudobulbar symptoms)

100

Where do the ICA's come from?

Right one from the brachiocephalic artery. Left one straight from the aortic arch.

101

Basilar artery into Circle of Willis anatomy?

Superior cerebellar arteries come off 1st, THEN the posterior cerebral arteries!

102

Where do the vertebral arteries come from?

Right one from braciocephalic artery (after R ICA). Left one from the subclavian artery.

103

AICA vs. PICA?

PICA's off the vertebral arteries. AICA's at junction with basilar artery.

104

A1 vs. A2 ACA?

A1 between MCA and ACom. A2 after Acom.

105

P1 vs. P2 PCA?

P2 after PCom. P1 between Pom and Basilar before Superior cerebellar arteries.

106

Two numbers to know for cerebral blood flow.

PO2 < 50 mmHg ---> increased cerebral perfusion pressure. PCO2 > 90 mmHg is LIMIT to increasing cerebral blood flow (via vasodilation) in proportion to PCO2.

107

Therapeutic hyperventilation?

By decreasing PCo2, we decreased cerebral blood flow and therefore intracranial pressure. Used for stroke, trauma.

108

MCA stroke

Contralateral paralysis of upper limb and face. Contralateral loss of sensation in upper and lower limbs, and face. Aphasia if dominant or hemineglect if non-dominant.

109

ACA stroke

Contralateral paralysis and loss of sensation in the LOWER limb. (B/c ACA perfuses in the middle-inside portion of brain.

110

Common location of lacunar stroke?

Internal capsule of the striatum supplied by lenticulotriate artery.

111

ASA (anterior spinal artery) stroke

Complete motor paralysis. Loss of pain and temp b/l. Retained propioception.

112

PICA stroke

Lateral Medullary syndrome - dec. pain and temp from ipsilateral face and contralateral body, dysphagia, hoarseness, dec. gag, ipsilateral Horner, ataxia

113

AICA stroke

Lateral pontine syndrome - vertigo, vomiting, nystagmus, falling over to side, ipsi facial paralysis and loss of sensation

114

PCA stroke

Contralateral hemianopia w/ macular sparing

115

Basilar artery stroke

Locked-in syndrome.

116

ACom lesion

Most commonly from aneurysm. Visual field deficits.

117

PCom lesion

Saccular aneurysm. CN III palsy.

118

Berry aneurysm

Occurs at bifurcations in Circle of Willis. e.g. Acom and ACA. Rupture to SAH. Associated with ADPKD, Ehlers-Danlos, Marfan. Age, HTN, smoking.

119

Charcot-Bouchard microaneurysm

Associated with chronic HTN, affecting small vessels

120

Crossing hematomas. Epidural vs. subdural?

Epidural will cross Falx and tentorium but NOT sutures. Subdural is exact opposite.