Snapshot A 35-year-old woman presents to the emergency department with lower extremity weakness and double vision. Past medical history is significant for multiple sclerosis which is treated with Rituximab. Physical examination is significant for 2/5 strength in the bilateral lower extremity as well as right-sided internuclear ophthalmoplegia. MRI of the brain and spine shows new hyperintense lesions. (Lesion affecting the medial longitudinal fasciculus) Introduction Select Central Nervous System Lesions Lesion Clinical Features Frontal lobe Frontal lobe lesions can result in disinhibition and an impairment in judgment orientation concentration frontal release signs magnetic gait Frontal eye field (FEF) lesions can result in eye deviation towards the side of the lesion an example is a stroke affecting the FEF Parietal lobe Lesions affecting the dominant parietal (usually the left) cortex results in Gerstmann's syndrome agraphia acalculia finger agnosia right-left confusion non-dominant (usually the right) parietal cortex results in contralateral hemineglect distortion of perceived space extinction Temporal lobe Lesions affecting the superior temporal lobe (Wernicke area) can result Wernicke aphasia and a right superior quadrant visual defect Lesions affecting limbic structures can result in deficits in consolidation and behavioral changes Seizures in the medial temporal lobe limbic structures results in emotions such as fear deja vu olfactory hallucinations Bilateral lesions in the amygdala results in Kluver-Bucy syndrome Brainstem Lesions affecting the superior colliculus Parinaud syndrome reticular activating system decreased consciousness and coma basal ganglia resting tremor chorea athetosis medial longitudinal fasciculus internuclear ophthalmoplegia paramedian pontine reticular formation eyes look aways from the side of the lesion