PonsUpper ExtremityBrain StemUpper Gastrointestinal TractBrain Stem NeoplasmsBrainMedulla OblongataMagnetic Resonance ImagingBrain Stem InfarctionsMyelinolysis, Central PontineCerebellumReticular FormationOlivopontocerebellar AtrophiesRespirationCerebellar DiseasesMesencephalonDysarthriaPolandTrigeminal NerveCerebellar AtaxiaAryldialkylphosphatasePyramidal TractsNeural PathwaysLaughter