Wiener-Kernel Analysis of Responses to Noise of Chinchilla Auditory-Nerve Fibers

1 Department of Communication Sciences and Disorders, Institute for Neuroscience and Hugh Knowles Center, Northwestern University, Evanston, Illinois; 2 Department of Otorhinolaryngology, University Hospital Groningen, School of Behavioral and Cognitive Neurosciences, University of Groningen, Groningen, The Netherlands; and 3 Department of Physiology, University of Wisconsin, Madison, Wisconsin Submitted 25 August 2004; accepted in final form 13 January 2005 Responses to broadband Gaussian white noise were recorded in auditory-nerve fibers of deeply anesthetized chinchillas and analyzed by computation of zeroth-, first-, and second-order Wiener kernels. The first-order kernels (similar to reverse correlations or "revcors") of fibers with characteristic frequency (CF) 2 kHz decreased with increasing CF at a rate of about –18 dB per octave. However, residual first-order kernels could be detected in fibers with CF as high as 12 kHz. Second-order kernels, 2-dimensional matrices, reveal prominent periodicity at the CF frequency, regardless of CF. Thus onset delays, frequency glides, and near-CF group delays could be estimated for auditory-nerve fibers innervating the entire length of the chinchilla cochlea. Address for reprint requests and other correspondence: M. A. Ruggero, Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Drive, Evanston, IL 60208-3550 (E-mail: mruggero{at}northwestern.edu )