A study of active artificial hair cell models inspired by outer hair cell somatic motility

2016 ◽  
Vol 28 (6) ◽  
pp. 811-823 ◽  
Author(s):  
Bryan S Joyce ◽  
Pablo A Tarazaga
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Dynamic Range ◽  
Outer Hair Cells ◽  
Quality Factors ◽  
Control Laws ◽  
Sensor Performance ◽  
Nonlinear Amplification ◽  
Key Aspects

The cochlea displays an important, nonlinear amplification of sound-induced oscillations. In mammals, this amplification is largely powered by the somatic motility of the outer hair cells. The resulting cochlear amplifier has three important characteristics useful for hearing: an amplification of responses from low sound pressures, an improvement in frequency selectivity, and an ability to transduce a broad range of sound pressure levels. These useful features can be incorporated into designs for active artificial hair cells, bio-inspired sensors for use as microphones, accelerometers, or other dynamic sensors. The sensor consists of a cantilever beam with piezoelectric actuators. A feedback controller applies a voltage to the actuators to mimic the outer hair cells’ somatic motility. This article describes three control laws for an active artificial hair cell inspired by models of the outer hair cells’ somatic motility. The first control law is based on a phenomenological model of the cochlea while the second and third models incorporate physiological aspects of the biological cochlea to further improve sensor performance. Simulations show that these models qualitatively reproduce the key aspects of the mammalian cochlea, namely, amplification of oscillations from weak stimuli, higher quality factors, and a wider input dynamic range.

Passive compliance and active force generation in the guinea pig outer hair cell

1995 ◽  
Vol 74 (6) ◽  
pp. 2319-2328 ◽  
Author(s):  
R. Hallworth
Keyword(s):  
Hair Cell ◽  
Cell Motility ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Outer Hair Cells ◽  
Force Generation ◽  
Axial Stiffness ◽  
Sinusoidal Voltage ◽  
Apparent Stiffness ◽  
Outer Hair Cell Motility

1. Cochlear outer hair cells 20-80 microns in length were compressed axially in vitro using calibrated glass fibers mounted on a piezoelectric actuator. 2. When driven by rectangular pulses in the compression direction, the motion of the fiber tip consisted of a rapid initial compression that was complete in 10-20 ms followed by a smaller compression of slower time course. 3. The initial fiber deflections were found to be linear in amplitude for compressions up to 400 nm. The axial compliances of outer hair cells were calculated from the difference between the fiber tip motions when unattached and when in contact with a cell. Axial compliances were found to be in the range of 0.04-1.2 km/N for 149 cells. The axial compliance was an increasing function of cell length. 4. The peak forces generated by electrically stimulated outer hair cells were measured from the deflection of a glass fiber when the cells were stimulated by sinusoidal voltage commands. The slope gains of force generation (force generated per mV of command at the cell membrane) were estimated to range from 0.01 to 100 pN/mV. Most of the results fell in the range of 0.1-20 pN/mV. 5. When the apparent stiffness of the fiber was increased by moving the cell closer to the fiber base, the peak amplitude of the fiber deflection generated by the cell decreased and the peak force increased, for the same sinusoidal voltage command. 6. The results of the previous experiment were interpreted in the light of a model of outer hair cell motility in which an ideal extension generating element is in series with an internal stiffness element. This internal stiffness was then calculated for 13 cells. 7. The internal stiffnesses of cells calculated by the above procedure were found to be positively correlated with the axial stiffness measurements obtained for the same cells. 8. The implications of the above results for the effectiveness of outer hair cell motility in vivo are discussed.

scholarly journals Unmyelinated type II afferent neurons report cochlear damage

2015 ◽  
Vol 112 (47) ◽  
pp. 14723-14727 ◽  
Author(s):  
Chang Liu ◽  
Elisabeth Glowatzki ◽  
Paul Albert Fuchs
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Cell Damage ◽  
Large Diameter ◽  
Outer Hair Cells ◽  
Type I ◽  
Type Ii ◽  
Inner Hair Cell ◽  
Hair Cell Damage

In the mammalian cochlea, acoustic information is carried to the brain by the predominant (95%) large-diameter, myelinated type I afferents, each of which is postsynaptic to a single inner hair cell. The remaining thin, unmyelinated type II afferents extend hundreds of microns along the cochlear duct to contact many outer hair cells. Despite this extensive arbor, type II afferents are weakly activated by outer hair cell transmitter release and are insensitive to sound. Intriguingly, type II afferents remain intact in damaged regions of the cochlea. Here, we show that type II afferents are activated when outer hair cells are damaged. This response depends on both ionotropic (P2X) and metabotropic (P2Y) purinergic receptors, binding ATP released from nearby supporting cells in response to hair cell damage. Selective activation of P2Y receptors increased type II afferent excitability by the closure of KCNQ-type potassium channels, a potential mechanism for the painful hypersensitivity (that we term “noxacusis” to distinguish from hyperacusis without pain) that can accompany hearing loss. Exposure to the KCNQ channel activator retigabine suppressed the type II fiber’s response to hair cell damage. Type II afferents may be the cochlea’s nociceptors, prompting avoidance of further damage to the irreparable inner ear.

scholarly journals The Effects of Urethane on Rat Outer Hair Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Mingyu Fu ◽  
Mengzi Chen ◽  
Xiao Yan ◽  
Xueying Yang ◽  
Jinfang Xiao ◽  
...  
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Electrical Response ◽  
Outward Current ◽  
Outer Hair Cells ◽  
Dependent Manner ◽  
Cochlear Microphonic ◽  
Patch Clamp Recording ◽  
Electrical Impulses

The cochlea converts sound vibration into electrical impulses and amplifies the low-level sound signal. Urethane, a widely used anesthetic in animal research, has been shown to reduce the neural responses to auditory stimuli. However, the effects of urethane on cochlea, especially on the function of outer hair cells, remain largely unknown. In the present study, we compared the cochlear microphonic responses between awake and urethane-anesthetized rats. The results revealed that the amplitude of the cochlear microphonic was decreased by urethane, resulting in an increase in the threshold at all of the sound frequencies examined. To deduce the possible mechanism underlying the urethane-induced decrease in cochlear sensitivity, we examined the electrical response properties of isolated outer hair cells using whole-cell patch-clamp recording. We found that urethane hyperpolarizes the outer hair cell membrane potential in a dose-dependent manner and elicits larger outward current. This urethane-induced outward current was blocked by strychnine, an antagonist of theα9 subunit of the nicotinic acetylcholine receptor. Meanwhile, the function of the outer hair cell motor protein, prestin, was not affected. These results suggest that urethane anesthesia is expected to decrease the responses of outer hair cells, whereas the frequency selectivity of cochlea remains unchanged.

scholarly journals Persistence of Cav1.3 Ca2+ Channels in Mature Outer Hair Cells Supports Outer Hair Cell Afferent Signaling

2007 ◽  
Vol 27 (24) ◽  
pp. 6442-6451 ◽  
Author(s):  
M. Knirsch ◽  
N. Brandt ◽  
C. Braig ◽  
S. Kuhn ◽  
B. Hirt ◽  
...  
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Outer Hair Cells ◽  
Afferent Signaling ◽  
Ca2 Channels

Morphology of Synapses at the Base of Hair Cells in the Organ of Corti of the Chimpanzee

1990 ◽  
Vol 99 (3) ◽  
pp. 215-220 ◽  
Author(s):  
Joseph B. Nadol ◽  
Barbara J. Burgess
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Single Neuron ◽  
Outer Hair Cell ◽  
Mammalian Species ◽  
Organ Of Corti ◽  
Outer Hair Cells ◽  
Nerve Terminals ◽  
Section Electron ◽  
Serial Section Electron Microscopy

The synaptic morphology of inner and outer hair cells of the organ of Corti of the chimpanzee was evaluated by serial section electron microscopy. The morphology of nerve terminals and synapses at both sites was very similar to that of human and other mammalian species. Two types of nerve terminals, nonvesiculated and vesiculated, with distinct synaptic morphology were found. In addition, between some nonvesiculated endings and outer hair cells, a reciprocal synaptic relationship was seen. In such terminals there was morphologic evidence for transmission from hair cell to neuron and from neuron to hair cell between a single neuron and an outer hair cell.

Reciprocal Synapses at the Base of Outer Hair Cells in the Organ of Corti of Man

1981 ◽  
Vol 90 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Joseph B. Nadol
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Organ Of Corti ◽  
Postsynaptic Membrane ◽  
Opposite Polarity ◽  
Outer Hair Cells ◽  
Human Organ ◽  
Single Nerve ◽  
Small Collection

Reciprocal synapses have been found between nerve terminals and the outer hair cells in the human organ of Corti. A single nerve ending of the nonvesiculated type may possess two types of synaptic specialization of opposite polarity. The first is typical of the “afferent” synapse with a presynaptic body in the hair cell and pre- and postsynaptic membrane thickening. The second consists of a small collection of presynaptic vesicles in the neural cytoplasm near the plasma membrane facing the hair cell and a subsynaptic cisterna within the hair cell cytoplasm. The second type of specialization is similar to the synapses seen in “efferent” endings. This suggests that both an afferent (hair cell to neuron) and efferent (neuron to hair cell) synaptic relationship may exist between an outer hair cell and a single nerve terminal.

Oral Ethanol Potentiates the Loss of Outer Hair Cells in Cisplatin-Exposed Rats

2007 ◽  
Vol 137 (2) ◽  
pp. 327-331 ◽  
Author(s):  
Dilip Madnani ◽  
Geming Li ◽  
Christopher M. Frenz ◽  
Dorothy A. Frenz
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Fold Increase ◽  
Cell Loss ◽  
Saline Group ◽  
Outer Hair Cells ◽  
Hair Cell Loss ◽  
Auditory Hair Cells ◽  
Ethanol Group

OBJECTIVE: The aim of this study was to examine the effect of oral ethanol on cisplatin ototoxicity. STUDY DESIGN AND SETTING: Twenty-seven-week-old, female Fisher 344 rats were divided into 4 experimental groups. The animals were administered per os (PO) saline (group 1), PO ethanol (group 2), PO saline with intraperitoneal (IP) cisplatin (group 3), or PO ethanol with IP cisplatin (group 4). After 3 days, scanning electron microscopy and counts of outer auditory hair cells were performed. RESULTS: A 2-fold increase in outer hair cell loss was obtained in the basal cochlear turn of rats receiving concomitant cisplatin and ethanol compared with animals receiving cisplatin and saline. No hair cell loss was observed in the middle cochlear turn of any experimental group. CONCLUSION: Our findings support potentiation of ototoxicity when cisplatin is combined with oral ethanol. SIGNIFICANCE: Contraindications for alcohol use in cancer patients receiving cisplatin are implicated.

scholarly journals Neuroplastin Isoform Np55 Is Expressed in the Stereocilia of Outer Hair Cells and Required for Normal Outer Hair Cell Function

2016 ◽  
Vol 36 (35) ◽  
pp. 9201-9216 ◽  
Author(s):  
W.-Z. Zeng ◽  
N. Grillet ◽  
J. B. Dewey ◽  
A. Trouillet ◽  
J. F. Krey ◽  
...  
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Cell Function ◽  
Outer Hair Cells

Properties of auditory nerve responses in absence of outer hair cells

1978 ◽  
Vol 41 (2) ◽  
pp. 365-383 ◽  
Author(s):  
P. Dallos ◽  
D. Harris
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Auditory Nerve ◽  
Outer Hair Cell ◽  
Nerve Fibers ◽  
Outer Hair Cells ◽  
Border Region ◽  
Histological Evaluation ◽  
High Threshold ◽  
Time Pattern

1. Recordings were made from chinchilla auditory nerve fibers after portions of the cochlear outer hair cell (OHC) population were destroyed with the antibiotic kanamycin. In most cases the inner hair cell (IHC) population was completely preserved as determined by phase-contrast microscopy. We presume that the remaining IHCs are functionally normal, and thus that recordings obtained from fibers originating from the lesioned cochlear segment reflect IHC behavior. 2. Behavioral thresholds were measured for all animals both before and after the production of the cochlear lesion. The audiograms and the histological evaluation of the ears were the basis for assessing whether a particular fiber originated in a normal, pathological (shifted threshold; IHC only), or border region. These criteria also identified the animals that sustained IHC damage together with the destruction of part of the OHC population. Only the data obtained from those fibers which probably originated from the OHC-free segment of the cochlea are considered in detail. 3. Fibers whose characteristic frequency (CF) identified them as belonging to the normal (audiometrically and histologically) region, were found to be normal in all respects. 4. Fibers from the border region (where the audiogram has a steep slope between normal and hearing-loss regions probably corresponding to the segment where OHC loss progresses from less than 10% to more than 90%) had very complex response patterns. Their frequency threshold curves (FTC) showed great variability. In general, the closer the fiber was to the fully developed lesion, the more abnormal its FTC became. 5. Those units that were concluded to have originated from the OHC-free part of the cochlea could be divided into three categories on the basis of the shape of their FTCs. A small fraction had very broad tuning (9%). The majority (53%) had approximately normal tail segment, normal bandwidth of the tip segment, and highly elevated threshold at CF. A group of fibers (38%) could not be assigned a CF. Probably the FTC of most of these latter fibers are similar to those of the previous group, but the sharply tuned short tip segment was either missed or was not reachable on account of its extremely high threshold level. 6. Such indexes of fiber response as latency, spontaneous rate, and time pattern (PST histograms) were not affected by the loss of OHCs. 7. On the basis of the data and of the assumptions made it was suggested that outer hair cells provide a frequency-dependent sensitizing influence to the inner hair cells. The frequency dependence could best be expressed as a flat-topped band pass characteristic.

Psychophysical Tuning Curves in Subjects with Tinnitus Suggest Outer Hair Cell Lesions

1995 ◽  
Vol 113 (3) ◽  
pp. 223-233 ◽  
Author(s):  
Curtin R. Mitchell ◽  
Thomas A. Creedon
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Tuning Curve ◽  
Control Design ◽  
Nerve Fibers ◽  
Outer Hair Cells ◽  
Tuning Curves ◽  
Hearing Thresholds

A study by Penner (J Speech Hear Res 1980;23:779–86) found evidence for Impaired lateral suppression in subjects with tinnitus and sensorineural hearing loss. If lateral suppression is related to tuning curve sharpness and lateral suppression is impaired, the shape of the tuning curve should be affected. The purpose of this study was to determine whether subjects with tinnitus have psychophysical tuning curves that are different from those of subjects without tinnitus. Psychophysical tuning curves and hearing thresholds were obtained from 18 subjects, 7 with tinnitus and 11 without tinnitus. Only subjects with normal audiograms (through 8 kHz) were selected for this study. In subjects with tinnitus psychophysical tuning curves were obtained in the region pitch-matched to their tinnitus. In nontinnitus subjects psychophysical tuning curves were determined at the same frequencies as for the tinnitus subjects in a yoked-control design. The slopes of the tails and tips and the Q10 and other measures were calculated for each tuning curve. The psychophysical tuning curves in subjects with tinnitus were significantly different (0.01 level) from those of control subjects and often had hypersensitive tails and some elevated tips. These shapes of tuning curves are consistent with cochlear lesions involving the loss of outer hair cells without damage to the Inner hair cells or nerve fibers.

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