scholarly journals Motion of organ of Corti structures in the gerbil cochlear apex, measured with a commercial optical coherence tomography (OCT) system

2018 ◽  
Author(s):  
Michael E. Ravicz ◽  
Nam-Hyun Cho ◽  
Nima Maftoon ◽  
Sunil Puria
Keyword(s):  
Optical Coherence Tomography ◽  
Organ Of Corti ◽  
Optical Coherence

Measurement ofin vivobasal-turn vibrations of the organ of Corti using phase-sensitive Fourier domain optical coherence tomography

2013 ◽  
Author(s):  
Sripriya Ramamoorthy ◽  
Yuan Zhang ◽  
Tracy Petrie ◽  
Fangyi Chen ◽  
Hrebesh M. Subhash ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Organ Of Corti ◽  
Fourier Domain ◽  
Optical Coherence ◽  
Phase Sensitive

In vivo measurement of amplifying motion within the organ of Corti under sound stimulation using optical coherence tomography

2012 ◽  
Author(s):  
Niloy Choudhury ◽  
Fangyi Chen ◽  
Dingjun Zha ◽  
Anders Fridberger ◽  
Jiefu Zheng ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Organ Of Corti ◽  
Optical Coherence ◽  
Sound Stimulation ◽  
In Vivo Measurement

scholarly journals Multiple Wavelength Optical Coherence Tomography Assessments for Enhanced Ex Vivo Intra-Cochlear Microstructural Visualization

Electronics ◽  
2018 ◽  
Vol 7 (8) ◽  
pp. 133 ◽  
Author(s):  
Sungwook Kim ◽  
Ruchire Wijesinghe ◽  
Jaeyul Lee ◽  
Muhammad Shirazi ◽  
Pilun Kim ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
High Resolution ◽  
Wavelength Range ◽  
Basilar Membrane ◽  
Ex Vivo ◽  
Organ Of Corti ◽  
Depth Range ◽  
Optical Coherence ◽  
Multiple Wavelength ◽  
Multiple Wavelengths

The precise identification of intra-cochlear microstructures is an essential otorhinolaryngological requirement to diagnose the progression of cochlea related diseases. Thus, we demonstrated an experimental procedure to investigate the most optimal wavelength range, which can enhance the visualization of ex vivo intra-cochlear microstructures using multiple wavelengths (i.e., 860 nm, 1060 nm, and 1300 nm) based optical coherence tomography (OCT) systems. The high-resolution tomograms, volumetric, and quantitative evaluations obtained from Basilar membrane, organ of Corti, and scala vestibule regions revealed complementary comparisons between the aforementioned three distinct wavelengths based OCT systems. Compared to 860 nm and 1300 nm wavelengths, 1060 nm wavelength OCT was discovered to be an appropriate wavelength range verifying the simultaneously obtainable high-resolution and reasonable depth range visualization of intra-cochlear microstructures. Therefore, the implementation of 1060 nm OCT can minimize the necessity of two distinct OCT systems. Moreover, the results suggest that the performed qualitative and quantitative analysis procedure can be used as a powerful tool to explore further anatomical structures of the cochlea for future studies in otorhinolaryngology.

scholarly journals Organ of Corti vibration within the intact gerbil cochlea measured by volumetric optical coherence tomography and vibrometry

2018 ◽  
Vol 120 (6) ◽  
pp. 2847-2857 ◽  
Author(s):  
Wei Dong ◽  
Anping Xia ◽  
Patrick D. Raphael ◽  
Sunil Puria ◽  
Brian Applegate ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
High Frequency ◽  
Mechanical Response ◽  
Low Frequency ◽  
Organ Of Corti ◽  
Corner Frequency ◽  
Gradual Transition ◽  
Optical Coherence ◽  
Pass Filter ◽  
Low Pass Filter

There is indirect evidence that the mammalian cochlea in the low-frequency apical and the more commonly studied high-frequency basal regions function in fundamentally different ways. Here, we directly tested this hypothesis by measuring sound-induced vibrations of the organ of Corti (OoC) at three turns of the gerbil cochlea using volumetric optical coherence tomography vibrometry (VOCTV), an approach that permits noninvasive imaging through the bone. In the apical turn, there was little frequency selectivity, and the displacement-vs.-frequency curves had low-pass filter characteristics with a corner frequency of ~0.5–0.9 kHz. The vibratory magnitudes increased compressively with increasing stimulus intensity at all frequencies. In the middle turn, responses were similar except for a slight peak in the response at ~2.5 kHz. The gain was ~50 dB at the peak and 30–40 dB at lower frequencies. In the basal turn, responses were sharply tuned and compressively nonlinear, consistent with observations in the literature. These data demonstrated that there is a transition of the mechanical response of the OoC along the length of the cochlea such that frequency tuning is sharper in the base than in the apex. Because the responses are fundamentally different, it is not appropriate to simply frequency shift vibratory data measured at one cochlear location to predict the cochlear responses at other locations. Furthermore, this means that the number of hair cells stimulated by sound is larger for low-frequency stimuli and smaller for high-frequency stimuli for the same intensity level. Thus the mechanisms of central processing of sounds must vary with frequency. NEW & NOTEWORTHY A volumetric optical coherence tomography and vibrometry system was used to probe cochlear mechanics within the intact gerbil cochlea. We found a gradual transition of the mechanical response of the organ of Corti along the length of the cochlea such that tuning at the base is dramatically sharper than that at the apex. These data help to explain discrepancies in the literature regarding how the cochlea processes low-frequency sounds.

scholarly journals Watching Death in the Gerbil Cochlea Using Optical Coherence Tomography (OCT)

2021 ◽  
Author(s):  
Nam Hyun Cho ◽  
Haobing Wang ◽  
Sunil Puria
Keyword(s):  
Optical Coherence Tomography ◽  
Hair Cell ◽  
Outer Hair Cell ◽  
Round Window ◽  
Fluid Pressure ◽  
Organ Of Corti ◽  
Round Window Membrane ◽  
Tectorial Membrane ◽  
Optical Coherence

Because it is difficult to directly observe the morphology of the living cochlea, our ability to infer the mechanical functioning of the living ear has been limited. Nearly all of our knowledge about cochlear morphology comes from postmortem tissue that was fixed and processed using procedures that possibly distort the structures and fluid spaces of the organ of Corti. In this study, optical coherence tomography was employed to obtain in vivo and postmortem micron-scale volumetric images of the high-frequency hook region of the gerbil cochlea through the round-window membrane. The anatomical structures and fluid spaces of the organ of Corti were segmented and quantified in vivo and over a 90-minute postmortem period. The results show that some aspects of the organ of Corti are significantly altered over the course of death, such as the volumes of the fluid spaces, whereas the dimensions of other features change very little. We postulate that the fluid space of the outer tunnel and its surrounding tectal cells form a resonant structure that can affect the motion of the reticular lamina and thereby have a profound effect on outer-hair-cell transduction and thus cochlear amplification. In addition, the in vivo fluid pressure of the inner spiral sulcus is postulated to effectively inflate the connected sub-tectorial gap between the tectorial membrane and the reticular lamina. This gap height decreases after death, which is hypothesized to reduce and disrupt hair-cell transduction.

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