title: Amplitude-modulation detection by gerbils in reverberant sound fields.
abstract: Reverberation can dramatically reduce the depth of amplitude modulations which are critical for speech intelligibility. Psychophysical experiments indicate that humans' sensitivity to amplitude modulation in reverberation is better than predicted from the acoustic modulation depth at the receiver position. Electrophysiological studies on reverberation in rabbits highlight the contribution of neurons sensitive to interaural correlation. Here, we use a prepulse-inhibition paradigm to quantify the gerbils' amplitude modulation threshold in both anechoic and reverberant virtual environments. Data show that prepulse inhibition provides a reliable method for determining the gerbils' AM sensitivity. However, we find no evidence for perceptual restoration of amplitude modulation in reverberation. Instead, the deterioration of AM sensitivity in reverberant conditions can be quantitatively explained by the reduced modulation depth at the receiver position. We suggest that the lack of perceptual restoration is related to physical properties of the gerbil's ear input signals and inner-ear processing as opposed to shortcomings of their binaural neural processing.
authors.affiliation: Division of Neurobiology, Department Biology II, Ludwig-Maximilians-Universitaet Munich, Grosshaderner Str. 2-4, D-82152 Martinsried-Planegg, Germany. lingner@zi.biologie.uni-muenchen.de
authors.forename: Andrea
authors.initials: A
authors.lastname: Lingner
authors.forename: Kathrin
authors.initials: K
authors.lastname: Kugler
authors.forename: Benedikt
authors.initials: B
authors.lastname: Grothe
authors.forename: Lutz
authors.initials: L
authors.lastname: Wiegrebe
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology*; D001522:Behavior, Animal; D004423:Ear / Q000502:physiology; D004594:Electrophysiology; D004867:Equipment Design; D005849:Gerbillinae; D008297:Male; D009622:Noise; D016011:Normal Distribution; D010470:Perceptual Masking / Q000502:physiology; D011601:Psychophysics; D011984:Sensory Receptor Cells / Q000473:pathology; D013016:Sound; D013017:Sound Localization / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*