Generation of two-dimensional spatial and temporal properties through spatiotemporal convergence between one-dimensional neurons

Primary otolith afferents are characterized by diverse temporal and spatial response properties. The temporal properties of these neurons vary from tonic to phasic response characteristics during stimulation with linear acceleration. This study examines the response properties of target neurons that arise from spatiotemporal convergence (STC) between purely tonic and phasic-tonic afferents. The transfer function of the phasic-tonic afferent is described by either fractional leaky differentiator or integrator terms. Target neurons would generally exhibit two-dimensional spatial sensitivity and are characterized by two perpendicular response vectors. It is shown that target neurons have different temporal properties during stimulation along different spatial directions. Specifically, they could exhibit tonic temporal response dynamics during stimulation along the second response vector. The phasic dynamics along one response vector are described by a complete ideal differentiator for frequencies below the corner frequency of the leaky operator terms.