Summary

1. A partial lesion of the PPRF will produce a small phasic command and small (hypometric) saccades. A complete lesion of the PPRF will abolish all ipsilateral saccades (in this case to the left).
2. If the projection from PPRF to the motoneurons is damaged only a tonic command, through PPH, will get to the motorneurons and thus the saccade will be very slow.
3. If the PPH is lesioned the saccade will be normal but, because the tonic command is deficient, the eye will drift back.