New variations on the derivation of spectro-temporal receptive fields for primary auditory afferent axons.

The spectro-temporal receptive field [Hear. Res 5 (1981) 147; IEEE Trans BME 15 (1993) 177] provides an explicit image of the spectral and temporal aspects of the responsiveness of a primary auditory afferent axon. It exhibits the net effects of the competition between excitatory and inhibitory (or suppressive) phenomena. In this paper, we introduce a method for derivation of the spectro-temporal receptive field directly from a second-order Wiener kernel (produced by second-order reverse correlation between spike responses and broad-band white-noise stimulus); and we expand the concept of the spectro-temporal receptive field by applying the new method not only to the second-order kernel itself, but also to its excitatory and inhibitory subkernels. This produces separate spectro-temporal images of the excitatory and inhibitory phenomena putatively underlying the competition. Applied, in simulations, to models with known underlying excitatory and suppressive tuning and timing properties, the method successfully extracted a faithful image of those properties for excitation and one for inhibition. Applied to three auditory axons from the frog, it produced images consistent with previously published physiology.