A multi-metric approach to characterizing mouse peripheral auditory nerve function using the auditory brainstem response

• Published in: Journal of neuroscience methods Vol. 346; p. 108937
• Main Authors: McClaskey, Carolyn M., Panganiban, Clarisse H., Noble, Kenyaria V., Dias, James W., Lang, Hainan, Harris, Kelly C.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2020
• Subjects: Acoustic Stimulation; Animals; Auditory brainstem response (ABR); Auditory Threshold; Cochlear Nerve; Evoked Potentials, Auditory, Brain Stem; Mice; Mice, Inbred CBA; Mouse auditory nerve (AN); Neural synchrony; Noise; Suprathreshold function; Mouse auditory nerve (AN); Auditory brainstem response (ABR); Neural synchrony; Suprathreshold function
• ISSN: 0165-0270; 1872-678X
• DOI: 10.1016/j.jneumeth.2020.108937

•We propose a novel method to characterize auditory nerve function in vivo in mice.•Six complementary metrics are quantified from the mouse auditory brainstem response.•This approach emphasizes suprathreshold levels and neural synchrony•We find evidence supporting the presence of heterogeneous auditory nerve fibers. The auditory brainstem response (ABR), specifically wave I, is widely used to noninvasively measure auditory nerve (AN) function. Recent work in humans has introduced novel electrocochleographic measures to comprehensively characterize AN function that emphasize suprathreshold processing and estimate neural synchrony. This study establishes new tools for evaluating AN function in vivo in adult mice using tone-evoked ABRs obtained from young-adult CBA/CaJ mice, adapting the approach previously introduced in humans. Six metrics are obtained from ABR wave I at suprathreshold stimulus levels. Change-point analyses show that the metrics’ rate of change with stimulus level differs between moderate and high suprathreshold levels, suggesting that this approach can potentially characterize the presence of heterogeneous AN fiber types. Traditional ABR approaches focus on response thresholds and averaged amplitudes/latencies. In contrast, our multi-metric approach, which uses single-trial data and suprathreshold stimuli, provides novel information and identifies evidence of neural synchrony deficits and changes in the heterogeneity of AN fibers underlying AN behavior. The techniques reported here provide a novel tool to assess changes in AN function in vivo in a commonly used animal model. A benchmark of most current hearing research is the transition from animal to human studies. Here we established a translational objective approach, applying methods that were first developed in humans to animals. This approach enables researchers to identify changes in AN function arising from the animal models with well-characterized pathology, and predict similar pathological changes in human AN dysfunction and hearing loss.