Dynamic Polarization Vector of Spatially Tuned Neurons

The study of the dynamic properties of otolith neurons has been difficult previously because of the differing response sensitivities of individual cells to specific stimulus directions and the lack of a general mathematical scheme that could explain and account for all their response features. The present paper describes a method for estimating both the spatial and temporal properties of neurons like the otolith neurons that are spatially tuned to different stimulus directions. At each stimulus frequency, a response ellipse can be constructed from the neural responses elicited by stimulation along three linear independent axes. The semimajor axis of the ellipse will specify the neuron’s direction of maximum sensitivity (polarization vector), whereas the semiminor axis will provide its sensitivity in the perpendicular direction. The predictions of the method for nonzero length of the semiminor axis are qualitatively the same as the experimentally observed dependance of response phase on stimulus orientation.