Browsing by Subject "Evoked Potentials, Auditory, Brain Stem"
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Item Open Access An operant-based detection method for inferring tinnitus in mice.(Journal of neuroscience methods, 2017-11) Zuo, Hongyan; Lei, Debin; Sivaramakrishnan, Shobhana; Howie, Benjamin; Mulvany, Jessica; Bao, JianxinBackground
Subjective tinnitus is a hearing disorder in which a person perceives sound when no external sound is present. It can be acute or chronic. Because our current understanding of its pathology is incomplete, no effective cures have yet been established. Mouse models are useful for studying the pathophysiology of tinnitus as well as for developing therapeutic treatments.New method
We have developed a new method for determining acute and chronic tinnitus in mice, called sound-based avoidance detection (SBAD). The SBAD method utilizes one paradigm to detect tinnitus and another paradigm to monitor possible confounding factors, such as motor impairment, loss of motivation, and deficits in learning and memory.Results
The SBAD method has succeeded in monitoring both acute and chronic tinnitus in mice. Its detection ability is further validated by functional studies demonstrating an abnormal increase in neuronal activity in the inferior colliculus of mice that had previously been identified as having tinnitus by the SBAD method.Comparison with existing methods
The SBAD method provides a new means by which investigators can detect tinnitus in a single mouse accurately and with more control over potential confounding factors than existing methods.Conclusion
This work establishes a new behavioral method for detecting tinnitus in mice. The detection outcome is consistent with functional validation. One key advantage of mouse models is they provide researchers the opportunity to utilize an extensive array of genetic tools. This new method could lead to a deeper understanding of the molecular pathways underlying tinnitus pathology.Item Open Access Optimizing non-invasive functional markers for cochlear deafferentation based on electrocochleography and auditory brainstem responses.(The Journal of the Acoustical Society of America, 2022-04) Harris, Kelly C; Bao, JianxinAccumulating evidence suggests that cochlear deafferentation may contribute to suprathreshold deficits observed with or without elevated hearing thresholds, and can lead to accelerated age-related hearing loss. Currently there are no clinical diagnostic tools to detect human cochlear deafferentation in vivo. Preclinical studies using a combination of electrophysiological and post-mortem histological methods clearly demonstrate cochlear deafferentation including myelination loss, mitochondrial damages in spiral ganglion neurons (SGNs), and synaptic loss between inner hair cells and SGNs. Since clinical diagnosis of human cochlear deafferentation cannot include post-mortem histological quantification, various attempts based on functional measurements have been made to detect cochlear deafferentation. So far, those efforts have led to inconclusive results. Two major obstacles to the development of in vivo clinical diagnostics include a lack of standardized methods to validate new approaches and characterize the normative range of repeated measurements. In this overview, we examine strategies from previous studies to detect cochlear deafferentation from electrocochleography and auditory brainstem responses. We then summarize possible approaches to improve these non-invasive functional methods for detecting cochlear deafferentation with a focus on cochlear synaptopathy. We identify conceptual approaches that should be tested to associate unique electrophysiological features with cochlear deafferentation.Item Open Access Otoprotective Effects of Stephania tetrandra S. Moore Herb Isolate against Acoustic Trauma.(Journal of the Association for Research in Otolaryngology : JARO, 2018-12) Yu, Yan; Hu, Bing; Bao, Jianxin; Mulvany, Jessica; Bielefeld, Eric; Harrison, Ryan T; Neton, Sarah A; Thirumala, Partha; Chen, Yingying; Lei, Debin; Qiu, Ziyu; Zheng, Qingyin; Ren, Jihao; Perez-Flores, Maria Cristina; Yamoah, Ebenezer N; Salehi, PezhmanNoise is the most common occupational and environmental hazard, and noise-induced hearing loss (NIHL) is the second most common form of sensorineural hearing deficit. Although therapeutics that target the free-radical pathway have shown promise, none of these compounds is currently approved against NIHL by the United States Food and Drug Administration. The present study has demonstrated that tetrandrine (TET), a traditional Chinese medicinal alkaloid and the main chemical isolate of the Stephania tetrandra S. Moore herb, significantly attenuated NIHL in CBA/CaJ mice. TET is known to exert antihypertensive and antiarrhythmic effects through the blocking of calcium channels. Whole-cell patch-clamp recording from adult spiral ganglion neurons showed that TET blocked the transient Ca2+ current in a dose-dependent manner and the half-blocking concentration was 0.6 + 0.1 μM. Consistent with previous findings that modulations of calcium-based signaling pathways have both prophylactic and therapeutic effects against neural trauma, NIHL was significantly diminished by TET administration. Importantly, TET has a long-lasting protective effect after noise exposure (48 weeks) in comparison to 2 weeks after noise exposure. The otoprotective effects of TET were achieved mainly by preventing outer hair cell damage and synapse loss between inner hair cells and spiral ganglion neurons. Thus, our data indicate that TET has great potential in the prevention and treatment of NIHL.