English: Illustration of lesions in "One and a half syndrome". The MLF connects the abducens nerve on one side with the occulomotor nerve on the contralateral side. The PPRF stimulates the abducens nerve ipsilaterally. The red block lines indicate the site of lesion. 1, at the level of MLF; 2 at the level of PPRF and 3 at the level of the 6th cranial nerve. Abbreviations: MLF, medial longitudinal fasciculus; PPRF, paramedian pontine reticular formation; III, cranial nerve 3 (occulomotor); VI, cranial nerve 6 (abducens).