1. Articles from Elizabeth S. Olson

    1-9 of 9
    1. Using volumetric optical coherence tomography to achieve spatially resolved organ of Corti vibration measurements

      Using volumetric optical coherence tomography to achieve spatially resolved organ of Corti vibration measurements

      Optical coherence tomography (OCT) has become a powerful tool for measuring vibrations within the organ of Corti complex (OCC) in cochlear mechanics experiments. However, the one-dimensional nature of OCT measurements, combined with experimental and anatomical constraints, make these data ambiguous: Both the relative positions of measured structures and their orientation relative to the direction of measured vibrations are not known a priori . We present a method by which these measurement features can be determined via the use of a volumetric OCT scan to determine the relationship between the imaging/measurement axes and the canonical anatomical axes. We provide evidence that ...

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    2. Salicylate-induced changes in organ of Corti vibrations

      Salicylate-induced changes in organ of Corti vibrations

      Intra organ of Corti (OC) vibrations differ from those measured at the basilar membrane (BM), with higher amplitudes and a wide-band nonlinearity extending well below a region’s best frequency. The vibrations are boosted by the cochlear amplifier, the active processes within the mammalian hearing organ, and are thus sensitive to metabolic or pharmacological manipulation. We introduced salicylate, a known blocker of outer hair cell (OHC) based electromotility, into the perilymphatic space by applying sodium salicylate onto the round window membrane. Vibration patterns of an area of the OC were mapped with phase sensitive optical coherence tomography before and after ...

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    3. Nonlinearity of intracochlear motion and local cochlear microphonic: Comparison between guinea pig and gerbil

      Nonlinearity of intracochlear motion and local cochlear microphonic: Comparison between guinea pig and gerbil

      Studying the in-vivo mechanical and electrophysiological cochlear responses in several species helps us to have a comprehensive view of the sensitivity and frequency selectivity of the cochlea. Different species might use different mechanisms to achieve the sharp frequency-place map. The outer hair cells (OHC) play an important role in mediating frequency tuning. In the present work, we measured the OHC-generated local cochlear microphonic (LCM) and the motion of different layers in the organ of Corti using optical coherence tomography (OCT) in the first turn of the cochlea in guinea pig. In the best frequency (BF) band, our observations were similar ...

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    4. Manipulation of the Endocochlear Potential Reveals Two Distinct Types of Cochlear Nonlinearity

      Manipulation of the Endocochlear Potential Reveals Two Distinct Types of Cochlear Nonlinearity

      The mammalian hearing organ, the cochlea, contains an active amplifier to boost the vibrational response to low level sounds. Hallmarks of this active process are sharp location-dependent frequency tuning and compressive nonlinearity over a wide stimulus range. The amplifier relies on outer hair cell (OHC) generated forces driven in part by the endocochlear potential (EP), the ̴ +80 mV potential maintained in scala media, generated by the stria vascularis. We transiently eliminated the EP in vivo by an intravenous injection of furosemide and measured the vibrations of different layers in the cochlea’s organ of Corti using optical coherence tomography. Distortion ...

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    5. Cochlear mechanics: new insights from vibrometry and Optical Coherence Tomography

      Cochlear mechanics: new insights from vibrometry and Optical Coherence Tomography

      The cochlea is a complex biological machine that transduces sound-induced mechanical vibrations to neural signals. Hair cells within the sensory tissue of the cochlea transduce vibrations into electrical signals, and exert electromechanical feedback that enhances the passive frequency separation provided by the cochlea's traveling wave mechanics; this enhancement is termed cochlear amplification. The vibration of the sensory tissue has been studied with many techniques, and the current state of the art is optical coherence tomography (OCT). The OCT technique allows for motion of intra-organ structures to be measured in vivo at many layers within the sensory tissue, at several ...

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    6. Scanning optical coherence tomography probe for in vivo imaging and displacement measurements in the cochlea

      Scanning optical coherence tomography probe for in vivo imaging and displacement measurements in the cochlea

      We developed a spectral domain optical coherence tomography (SDOCT) fiber optic probe for imaging and sub-nanometer displacement measurements inside the mammalian cochlea. The probe, 140 μm in diameter, can scan laterally up to 400 μm by means of a piezoelectric bender. Two different sampling rates are used, 10 kHz for high-resolution B-scan imaging, and 100 kHz for displacement measurements in order to span the auditory frequency range of gerbil (~50 kHz). Once the cochlear structures are recognized, the scanning range is gradually decreased and ultimately stopped with the probe pointing at the selected angle to measure the simultaneous displacements of ...

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    7. Adapting a commercial spectral domain optical coherence tomography system for time-locked displacement and physiological measurements

      Adapting a commercial spectral domain optical coherence tomography system for time-locked displacement and physiological measurements

      Measuring vibration within the cochlear partition is important to understand sound transduction and nonlinear amplification within the cochlea. Here we describe the customization of a commercially available Spectral Domain Optical Coherence Tomography system, the Thorlabs Telesto, for displacement measurements in the cochlea using a technique called Spectral Domain Phase Microscopy (SDPM). The paper describes the SDOCT data analysis pipeline composed of background subtraction, interpolation, and spectral shaping of the raw photodetector data, followed by the implementation of SDPM for vibration measurements. It also details the software and hardware modification necessary to couple the Telesto to a Tucker-Davis Technologies data acquisition ...

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    8. Optical coherence tomography reveals complex motion between the basilar membrane and organ of corti in the gerbil cochlea

      Optical coherence tomography reveals complex motion between the basilar membrane and organ of corti in the gerbil cochlea

      The mechanical basis of auditory transduction within the mammalian cochlea is not fully understood but relies on complex mechanical interactions between different structures within the Organ of Corti (OoC). We used spectral domain phase microscopy, a functional extension of optical coherence tomography (OCT), to measure the sound-evoked motion in response to “Zwuis” frequency complexes, in vivo, in the basal region of the gerbil cochlea. Because OCT allows for measurements from multiple axial positions along the optical path, we are able to simultaneously record vibration at different points within the OoC between the basilar membrane (BM) and tectorial membrane. Imaging through ...

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    9. Signal competition in optical coherence tomography and its relevance for cochlear vibrometry

      Signal competition in optical coherence tomography and its relevance for cochlear vibrometry

      The usual technique for measuring vibration within the cochlear partition is heterodyne interferometry. Recently, spectral domain phase microscopy (SDPM) was introduced and offers improvements over standard heterodyneinterferometry. In particular, it has a penetration depth of several mm due to working in the infrared range, has narrow and steep optical sectioning due to using a wideband light source, and is able to measure from several cochlear layers simultaneously. However, SDPM is susceptible to systematic error due to “phase leakage,” in which the signal from one layer competes with the signal from other layers. Here, phase leakage is explored in vibration measurements ...

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    1-9 of 9
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  2. Topics in the News

    1. (7 articles) Columbia University
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    Signal competition in optical coherence tomography and its relevance for cochlear vibrometry Optical coherence tomography reveals complex motion between the basilar membrane and organ of corti in the gerbil cochlea Adapting a commercial spectral domain optical coherence tomography system for time-locked displacement and physiological measurements Scanning optical coherence tomography probe for in vivo imaging and displacement measurements in the cochlea Cochlear mechanics: new insights from vibrometry and Optical Coherence Tomography Manipulation of the Endocochlear Potential Reveals Two Distinct Types of Cochlear Nonlinearity Nonlinearity of intracochlear motion and local cochlear microphonic: Comparison between guinea pig and gerbil Salicylate-induced changes in organ of Corti vibrations Using volumetric optical coherence tomography to achieve spatially resolved organ of Corti vibration measurements Influence of scan direction on subfoveal choroidal vascularity index using optical coherence tomography Subthreshold Nanosecond Laser for Non-resolving Central Serous Chorioretinopathy: A Double-masked Sham-controlled Randomised Trial Optical Coherence Tomography Angiography (OCTA) to Assess Cardiac Output and Cerebral Perfusion at the Time of Children's Cardiac Surgery