Neural Substrates for Vertical Saccades

• Vertical saccades originate from burst neurons in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF).
• The riMLF, like PPRF, produces the phasic command.
• Neurons in the interstitial nucleus of Cajal (INC) convert this to a tonic command (like the PPH for horizontal saccades).
• The phasic and tonic commands combine in the MN's in III & IV n.
• Both sides of the brainstem have neurons that generate upward saccades and others that generate downward saccades.
• Do neurons on each side do the same thing; i.e. is this a redundant representation?