title: Aging effects on the binaural interaction component of the auditory brainstem response in the Mongolian gerbil: Effects of interaural time and level differences.
abstract: The effect of interaural time difference (ITD) and interaural level difference (ILD) on wave 4 of the binaural and summed monaural auditory brainstem responses (ABRs) as well as on the DN1 component of the binaural interaction component (BIC) of the ABR in young and old Mongolian gerbils (Meriones unguiculatus) was investigated. Measurements were made at a fixed sound pressure level (SPL) and a fixed level above visually detected ABR threshold to compensate for individual hearing threshold differences. In both stimulation modes (fixed SPL and fixed level above visually detected ABR threshold) an effect of ITD on the latency and the amplitude of wave 4 as well as of the BIC was observed. With increasing absolute ITD values BIC latencies were increased and amplitudes were decreased. ILD had a much smaller effect on these measures. Old animals showed a reduced amplitude of the DN1 component. This difference was due to a smaller wave 4 in the summed monaural ABRs of old animals compared to young animals whereas wave 4 in the binaural-evoked ABR showed no age-related difference. In old animals the small amplitude of the DN1 component was correlated with small binaural-evoked wave 1 and wave 3 amplitudes. This suggests that the reduced peripheral input affects central binaural processing which is reflected in the BIC.
authors.affiliation: Cluster of Excellence Hearing4all, Animal Physiology and Behavior Group, Department for Neuroscience, School of Medicine and Health Sciences, Oldenburg University, 26111, Oldenburg, Germany. Electronic address: genevieve.laumen@uni-oldenburg.de.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Laumen
authors.affiliation: Department of Physiology and Biophysics, School of Medicine, University of Colorado, Aurora, CO, 80045, USA. Electronic address: Daniel.Tollin@ucdenver.edu.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Tollin
authors.affiliation: Cluster of Excellence Hearing4all, Animal Physiology and Behavior Group, Department for Neuroscience, School of Medicine and Health Sciences, Oldenburg University, 26111, Oldenburg, Germany. Electronic address: rainer.beutelmann@uni-oldenburg.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Beutelmann
authors.affiliation: Cluster of Excellence Hearing4all, Animal Physiology and Behavior Group, Department for Neuroscience, School of Medicine and Health Sciences, Oldenburg University, 26111, Oldenburg, Germany. Electronic address: georg.klump@uni-oldenburg.de.
authors.forename: Georg M
authors.initials: GM
authors.lastname: Klump
mesh_terms: D000161:Acoustic Stimulation; D000375:Aging; D000818:Animals; D001933:Brain Stem / Q000502:physiology*; D004566:Electrodes; D004569:Electroencephalography; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D005849:Gerbillinae; D006309:Hearing / Q000502:physiology; D006801:Humans; D008297:Male; D013016:Sound; D013017:Sound Localization / Q000502:physiology; D013569:Synapses / Q000502:physiology; D013997:Time Factors
keywords: BIC; Binaural hearing; ILD; ITD; Mammal; Superior olivary complex