Optimal response planes and canal convergence in secondary neurons in vestibular nuclei of alert cats.

Responses to natural stimulation were studied in electrically identified secondary vestibular neurons of awake cats. A class of neurons was identified whose response dynamics and responses to rotations in several vertical and horizontal planes indicated that they received semicircular canal input. Each canal neuron had clearly defined planes of maximal and null sensitivity to rotation. The orientation of these planes indicated that 44% of the neurons received input from one pair of canals, 40% from two, and 16% from all 3 canal pairs. Many cells also had oculomotor-related discharges and/or responded weakly to neck rotation.