Figure 1c: a. The scheme of sagittal view of the brainstem [14] shows the mechanism of convergence impairment in pontine tegmentum. The arrows indicate the hypothetic indirect pathway from NRTP to MLF in the pontine lesion of our case. MLF, medial longitudinal fasciculus; MRF, mesencephalic reticular formation; NRTP, nucleus reticularis tegmenti pontis; PN, pontine nuclei; PPRF, paramedian pontine reticular formation; V, fourth ventricle; III, oculomotor nucleus; IV, trochlear nucleus; VI, abducens nucleus. b. The scheme of horizontal view [15] shows the regions of NRTP and MLF, and indicated the lesion in our case.