thalamic lesions short

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