Estimating spatio-temporal receptive fields of auditory and visual neuronsfrom their responses to natural stimuli

We present a generalized reverse correlation technique that can be used to estimate the spatio-temporal receptive fields (STRFs) of sensory neurons fr om their responses to arbitrary stimuli such as auditory vocalizations or n atural visual scenes. The general solution for STRF estimation requires nor malization of the stimulus-response cross-correlation by the stimulus autoc orrelation matrix. When the second-order stimulus statistics are stationary , normalization involves only the diagonal elements of the Fourier-transfor med auto-correlation matrix (the power spectrum). In the non-stationary cas e normalization requires the entire auto-correlation matrix. We present mod elling studies that demonstrate the feasibility and accuracy of this method as well as neurophysiological data comparing STRFs estimated using natural versus synthetic stimulus ensembles. For both auditory and visual neurons, STRFs obtained with these different stimuli are similar, but exhibit syste matic differences that may be functionally significant. This method should be useful for determining what aspects of natural signals are represented b y sensory neurons and may reveal novel response properties of these neurons .