Four patients had anosognosia for hemiplegia (AHP) as a manifestation of po
ntine infarction in the mediolateral region. Patients with AHP syndrome had
no mental and neuropsychologic disturbances, and all had involvement of th
e medial or lateral part of the pens (medial or lateral pontine reticular n
uclei). Brainstem lesions, which activate frontoparietosubcortical areas, m
ay be a critical factor in the development of AHP syndrome.