Microsecond Precision of Phase Delay in the Auditory System of the Barn Owl

• Published in: Journal of neurophysiology 2005-08, Vol.94 (2), p.1655-1658
• Main Authors: Wagner, Hermann, Brill, Sandra, Kempter, Richard, Carr, Catherine E
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation - methods; Animals; Auditory Pathways - physiology; Auditory Perception - physiology; Auditory Threshold - physiology; Brain Stem - physiology; Dose-Response Relationship, Radiation; Evoked Potentials, Auditory - physiology; Fourier Analysis; Reaction Time - physiology; Strigiformes - physiology; Time Factors; Tyto alba
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.01226.2004

1 Institute for Biology II, Rheinisch-Westfölische Technische Hochschule Aachen, Aachen, Germany; 2 Department of Biology, University of Maryland, College Park, Maryland; and 3 Institute for Theoretical Biology, Humboldt University Berlin, and Neuroscience Research Centre, Charité Medical Faculty of Berlin, and Bernstein Center for Computational Neuroscience, Berlin, Germany Submitted 1 December 2004; accepted in final form 7 April 2005 The auditory system encodes time with sub-millisecond accuracy. To shed new light on the basic mechanism underlying this precise temporal neuronal coding, we analyzed the neurophonic potential, a characteristic multiunit response, in the barn owl's nucleus laminaris. We report here that the relative time measure of phase delay is robust against changes in sound level, with a precision sharper than 20 µs. Absolute measures of delay, such as group delay or signal-front delay, had much greater temporal jitter, for example due to their strong dependence on sound level. Our findings support the hypothesis that phase delay underlies the sub-millisecond precision of the representation of interaural time difference needed for sound localization. Address for reprint requests and other correspondence: H. Wagner, Institut für Biologie II, RWTH Aachen, Kopeinikusstra e 16, D-52074 Aachen