Auditory spatial receptive fields created by multiplication

Examples of multiplication by neurons or neural circuits are scarce, althou gh many computational models use this basic operation. The owl's auditory s ystem computes interaural time (ITD) and Level (ILD) differences to create a two-dimensional map of auditory space. Space-specific neurons are selecti ve for combinations of ITD and ILD, which define, respectively, the horizon tal and vertical dimensions of their receptive fields. A multiplication of separate postsynaptic potentials tuned to ITD and ILD, rather than an addit ion, can account for the subthreshold responses of these neurons to ITD-ILD pairs. Other nonlinear processes improve the spatial tuning of the spike o utput and reduce the fit to the multiplicative model.