Brain lesions Flashcards
Homunculus
Toes, legs at the top
Hand in the middle
Face and teeth at the bottol
Ex: lower extremity deficit in sensation or movement may indicate movement of the ACA.
Cerebral cortex function
Primary auditory cortex: in the temporal lobe
Arcuate fasciculus: parietal lobe
Premotor area: part of extra prymaidal circut, anterior to principal motor area.
Amygdala (bilateral) lesion
Kluver Bucy sydrome: hyperorality, hypersexuality, disinhibited behavior
Associated with HSV-1
Frontal lobe lesion
Disinhibition and deficits in concentration, orientation, and judgment; may have re-emergency of primitive reflexes
Right parietal lobe lesion
Spatial neglect syndrome
Agnosia of the contralateral side of the world
Reticular activating system (midbrain) lesion
Reduced levels of arousal and wakefulness (e.g. coma)
Mammillary bodies (bilateral) lesion
Wernicke-Korsakoff syndrome: confusion, opthalmoplegia, ataxia; memory loss, (antero and retrograde), confabulation, personality change
Associated with B1 deficiency, EtOH use.
Can be precipitated by giving glucose with B1 in B1 deficient patients.
Basal ganglia lesion
May result in tremor at rest, chorea, athetosis
Parkinson’s
Cerebellar hemisphere lesion
Intention tremor, limb ataxia, and loss of balance
Damage to the cerebellum results in ipsilateral deficits;
fall toward side of lesion
Cerebellar hemisphere are LATERALly located- thus affects LATERAL limbs
Cerebellar vermis lesion
Truncal ataxia, dysarthria
Vermis is centrally located–affected central body
Subthalamic nucleus lesion
Contralateral hemiballismus
Hippocampus lesion
Anterograde amnesia - inability to make new memories
Paramedian pontine reticular formation (PPRF) lesion
Eyes look away from side of lesion
vs. toward on frontal eye field lesion
Frontal eye field lesion
Eyes look toward lesion
vs. away in PPRF lesion
Central pontine myelinolysis
Acute paralysis, dysarthria, dysphagia, diplopia, and loss of conciousness
Can cause locked-in syndrome
Caused by overly rapid correction of hyponatremia
T2-weighted MRI with FLAIR shows abnormal increased signal in central pons.
Aphasia vs dysarthria
Aphasia= higher order inability to speak Dysarthria = motor inability to speak (movement deficit)
Broca’s
Nonfluent aphasia with intact comprehension.
Broca’s area- inferior frontal gyrus of frontal lobe
Wernicke’s
Fluent aphasia with impaired comprehension.
Wernicke’s- superior temporal gyrus of temporal lobe
Global aphasia
Both broca’ and werniche’s involved
Nonfluent aphasia with impaired comprehension
Conduction
Poor repetition but fluent speech, intact comprehension.
Can be caused by damage to arcuate fasciculus
Can’t repeat phrases such as “no ifs, ands, or buts.”
Watershed zone
Between anterior cerebral/middle cerebral, posterior cerebral/middle cerebral arteries.
Damage in severe hypotension => upper leg/upper arm weakness, defects in higher-order visual processing.
