- frontal eye fields initiate the excitatory signal for horizontal gaze and saccades formation. Damage to the frontal eye field will result in deviation of the eyes towards the side of the lesion — right MCA stroke
- Anterior Circulation — from internal carotid artery (ACA, MCA, lacunar, watershed) ★
- Posterior Circulation — from vertebral, basillar and posterior cerebral arteries, Brainstem stroke syndromes
- Lobar Hemorrhage (elderly + amyloid angiopathy)
- Aphasia (Broca vs Wernicke)
- Cerebellar Stroke
Visual Field Defects
Sensory Deficit Localization:
Strokes in many CNS locations can result in sensory loss and can be further localized according to the specific pattern:
- Primary somatosensory cortex: Deficits are contralateral to the lesion. Based on the blood supply and the somatotopic organization of the somatosensory cortex, sensory deficits do not often impact the face, arm, and leg equally. Other deficits related to nearby cortical areas (eg, motor weakness, aphasia) are usually present.
- Thalamus: The thalamic ventral posterior lateral nucleus receives input from the spinothalamic tract and dorsal columns, and the ventral posterior medial nucleus receives input from the trigeminal pathway. Damage to these nuclei (eg, ischemia, hemorrhage) may result in contralateral complete sensory loss (eg, touch, pain/temperature, vibration/proprioception).
- Lateral pons or medulla: Strokes in these areas can lead to contralateral loss of pain and temperature sensation of the body (due to impact of the spinothalamic tract) and the ipsilateral face (due to impact of the spinal trigeminal nucleus). Patients often have vertigo, ataxia, and bulbar weakness (ie, lateral medullary syndrome).
- Medial medulla: Damage to the medial lemniscus can result in contralateral loss of vibration and joint position sense. It is typically also associated with contralateral arm and/or leg weakness and ipsilateral tongue weakness (medial medullary syndrome).
- Spinal cord: Damage to the spinal cord causes specific patterns of sensation loss that do not impact the face.