Thalamic Functional Divisions
1. reticular (arousal) intralaminar (nociception)
2. sensory
3. motor
4. limbic
5. higher cognitive function
Four arteries that perfuse thalamus
1. Tuberothalamic (off of pcom)
2. Paramedian ( p1)
3. Inferolaterals (P2)
4. Posterior choroidal (P2)
12%
Tuberothalamic perfuses - reticular, intralaminar, VA, mamillothalamic tract, amygdalofugal pathway
Pathology - fluctuating arousal, impaired learning and memory, autobiographical memory,
"emotional facial paralysis" - volition but asymmetry when laughing crying
Left VL - anomia, acalculia, comprehension impaired, preserved repetition and reading.
Right VL - hemispatial neglect
contralateral clumsiness
***tuberothalamic confined to anterior (sparing VL/MD) - deficits in new learning/apathy
superimposition of temporally unrelated information parallel expression of mental activities - palipsychism
35%
Paramedian artery perfuses - MD, intralaminar nuclei (CL, CM Pf), periventricular, posteriomedial VL, ventro medial pulvinar
Pathology - neuropscyh disturbances in arousal and memory (left right asymmetry, langauge/visual)
hypophonia, perseveration, agitation, aggressive, apathy
bilateral infarct - deep coma, awake unresponsiveness sudden labile affect changes to mania, inappropriate social behaviors, lack of shame, perseveration
dysarthria!!!
utilization behaviors
thalamic dementia - amnestic syndrome cjd
chronotaraxis - prominent disorientation in time
neurological signs - asterixis, vertical gaze paresis, 6th nerve palsies, bilateral internuclear ophthalmoplegia
miosis, light sensitivity.
45%
Inferolateral artery
Pathology - sensory loss, impaired extremity movement, thalamic pain syndrome - no neuropsych
"thalamic hand" of Foix and Hillemand - flexed, pronated, thumb beneath four fingers, spares language
Principal - VP (M,L,I, pc)
thalamic pain Dejerine and Roussy 1906 hypesthesia, hemiparesis, hemiataxia
Medial branches - (MGN)
Inferolateral pulvinar - rostral and lateral pulvinar
8%
Posterior choroidal -
Lateral - LGN, LD, LP, inferolateral parts of pulvinar
rare - quadrantanopsia, impaired fast phase of optokinetc response opposite the lesion. contralateral hemibody numbness, mild aphasia
homonymous quadrantanopsia, horizontal sectoranopsia, hemisensory loss, transcortical aphasia, memory
Medial - MGN, posterior parts of CM and CL, pulvinar
pulvinar infarct created - hyperkinetic motor syndrome (ataxia, rubral tremor, dysotnia, myoclonus, chorea "jerky dystonic unsteady hand"
Recovery
prognosis is correlated w/volume of hematoma
LOC @ onset
motor weakness @ onset
presence of intraventricular extension/hydrocephalus
generally considered good when consider mortality, recovery of motor
cognitive/psychiatric persistence reported (rates not well established)
Diaschisis - a lesion in one brain region produces impairment in distant but connected region
