Biology subjects

Zosuls, A.

Publications and source records attributed to Zosuls, A..

3 recordsLinked to original sources

bioRxiv2026

Sound-Driven Motion of Human Cochlear Structures Depends on Organ of Corti Integrity

Optical coherence tomography (OCT) was used to image and measure the passive sound-driven displacements of cochlear structures in situ through the intact round window membrane of fresh human cadaveric specimens at 12 to 30 hours postmortem. We find that the anatomical integrity of the organ of Corti (OoC) affects cochlear structural motion. OoC with high integrity (erect with supporting cells) have small osseous spiral lamina (OSL) motion. Conversely, OoC with low integrity (flattened without supporting cells) have large OSL motion. For the ratio of motion between the basilar membrane (BM) and OSL (BM/OSL), OoC with high integrity has large BM/OSL motion while a cochlear partition without OoC has small BM/OSL motion. Furthermore, the high-integrity OoC has reticular lamina surface motion that is lower than the BM, whereas low-integrity OoC has similar reticular lamina and BM motion. This relationship between OoC anatomical integrity and cochlear structural motion will have consequential effects on sound transduction.

neuroscience↗

bioRxiv2025

Anatomical integrity of the human cochlea estimated with optical coherence tomography for future clinical application

The human cochlea is encased within the otic capsule, the densest bone in the body, posing significant challenges for anatomical imaging of cochlear structures. Because of difficult access and fragility of cochlear structures, our understanding of intracochlear anatomy has historically relied on postmortem histology. We thus have a limited understanding of human cochlear anatomy in its native, unfixed state. Clinical diagnostics for hearing loss, such as audiometry and otoacoustic emissions, offer functional assessments but fail to elucidate the often diverse underlying structural pathologies with any degree of precision. To address the critical need for assessing the human cochlear anatomy and associated pathologies without the risk of traumatizing cochlear structures, we imaged fresh cochleae in situ soon after death through the intact round window membrane with Optical Coherence Tomography (OCT) without inserting instruments inside or opening the cochlea. Micron-resolution OCT cross-sectional images of the human intracochlear structures were acquired and compared with corresponding histology systematically to aid in the identification of fine structural features and possible pathologies. With OCT imaging, we observed varied anatomy of the organ of Corti, and developed a cochlear "integrity" rating system to differentiate healthy appearing cochleae from various pathological states. These results demonstrate the capability of OCT to non-traumatically visualize cochlear integrity, highlighting its potential as a diagnostic tool. This work shows promise in translating the ability to determine the likelihood of existing or lack of hair cells and supporting cells in live patients, which would enable appropriate targeted treatments.

physiology↗

bioRxiv2018

Imaging forward and Reverse Traveling Waves in the Cochlea

The presence of forward and reverse traveling wave modes on the basilar membrane has important implications to how the cochlea functions as a filter, transducer, and amplifier of sound. The presence and parameters of traveling waves are of particular importance to interpreting otoacoustic emissions (OAE). OAE are vibrations that propagate out of the cochlea and are measureable as sounds emitted from the tympanic membrane. The interpretation of OAE is a powerful research and clinical diagnostic tool, but OAE use has not reached full potential because the mechanisms of their generation and propagation are not fully understood. Of particular interest and deliberation is whether the emissions propagate as a fluid compression wave or a structural traveling wave. In this study a mechanical probe was used to simulate an OAE generation site and optical imaging was used to measure displacement of the inner hair cell stereocilia of the gerbil cochlea. Inner hair cell stereocilia displacement measurements were made in the radial dimension as a function of their longitudinal location along the length of the basilar membrane in response to a transverse stimulation from the probe. The analysis of the spatial frequency response of the inner hair cell stereocilia at frequencies near the characteristic frequency (CF) of the measurement location suggests that a traveling wave propagates in the cochlear partition simultaneously basal and apical (forward and reverse) from the probe location. The traveling wave velocity was estimated to be 5.9m/s - 8m/s in the base (near CF of 29kHz - 40kHz) and 1.9m/s - 2.4m/s in the second turn (near CF of 2kHz - 3kHz). These results suggest that the cochlear partition is capable of supporting both forward and reverse traveling wave modes generated by a source driving the basilar membrane. This suggests that traveling waves in the cochlear partition contribute to OAE propagation.

biophysics↗