This chapter demonstrates the central processing of otolithic information, by comparing motoneuron output with primary otolith input. It focuses on the importance of canal-otolith convergence for extending the frequency response characteristics of motoneurons involved primarily, but not exclusively, in vertical/rotatory eye movements. The functional importance of canal-otolithic convergence in vertical/oblique motoneurons, and probably also in horizontal motoneurons, is to extend the working range over a much wider frequency band than is provided by the simple canal vestibulo-ocular reflex (VOR). This is particularly evident in trochlear motoneurons during roll rotation where the canal and otolith responses have the same polarity. At high frequencies, the canal system may, therefore, serve to compensate for the lag present in the otolith system in addition to its compensation for the visco-elastic properties of the eye. When the roll movement is stopped the responses of canal and otolith are of opposite polarities and may cancel one another. In this case, the canal response may serve to prevent the eye from overshooting its final position. On the other hand, the otolith input serves to compensate for the poor canal performance in the low frequency range and, of course, during static head displacement.