Abstract
The auditory brainstem response (ABR) test provides information about the inner ear (cochlea) and the central pathways for hearing. The ABR reflects the electrical responses of both the cochlear ganglion neurons and the nuclei of the central auditory pathway to sound stimulation (Zhou et al., 2006; Burkard et al., 2007). The ABR contains 5 identifiable wave forms, labeled as I-V. Wave I represents the summated response from the spiral ganglion and auditory nerve while waves II-V represent responses from the ascending auditory pathway. The ABR is recorded via electrodes placed on the scalp of an anesthetized animal. ABR thresholds refer to the lowest sound pressure level (SPL) that can generate identifiable electrical response waves. This protocol describes the process of measuring the ABR of small rodents (mouse, rat, guinea pig, etc.), including anesthetizing the mouse, placing the electrodes on the scalp, recording click and tone burst stimuli and reading the obtained waveforms for ABR threshold values. As technology continues to evolve, ABR will likely provide more qualitative and quantitative information regarding the function of the auditory nerve and brainstem pathways involved in hearing.
Keywords: Mouse, Inner ear, Cochlea, Hearing, ABR
Materials and Reagents
Equipment
Software
Procedure
All procedures and animal handling described in this protocol should be done according to approved national ethical guidelines and complied with all protocol requirements of the Institutional Animal Care and Use Committee. Notes:
Representative data
Figure 4. Representative graph of an ABR testing. ABR thresholds (decibels of sound pressure level, dBSPL) were measured in mice with normal ABR (Black, Blue and Green curves) and abnormal ABR (Red curve). The mice with abnormal ABR showed higher ABR thresholds at click stimulus and at tones stimuli (8, 16, and 32 kHz) when compared to mice with normal ABR.
Recipes
Acknowledgments
The authors would like to acknowledge the financial support provided by Hearing Research Inc (HRI) and by NIH (NIDCD) Grant #R01DC0130671.
References
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