Cochlea
Encyclopedia
The cochlea is the auditory portion of the inner ear
. It is a spiral-shaped cavity in the bony labyrinth
, making 2.5 turns around its axis, the modiolus
.
A core component of the cochlea is the Organ of Corti
, the sensory organ of hearing
, which is distributed along the partition separating fluid chambers in the coiled tapered tube of the cochlea.
The name is from the Latin for snail shell, which is from the Greek
κοχλίας kokhlias ("snail, screw"), from κόχλος kokhlos ("spiral shell") in reference to its coiled shape; the cochlea is coiled in most mammals, monotreme
s being the exceptions.
The lengthwise partition that divides most of the cochlea is itself a fluid-filled tube, the third scala. This central column is called the scala media
, or cochlear duct. Its fluid, endolymph
, also contains electrolytes and proteins, but is chemically quite different from perilymph. Whereas the perilymph is rich in sodium ions, the endolymph is rich in potassium ions, which produces an ionic, electrical potential.
The hair cells are arranged in four rows in the organ of Corti
along the entire length of the cochlear coil. Three rows consist of outer hair cells (OHCs) and one row consists of inner hair cells (IHCs). The inner hair cells provide the main neural output of the cochlea. The outer hair cells, instead, mainly receive neural input from the brain, which influences their motility as part of the cochlea's mechanical pre-amplifier. The input to the OHC is from the olivary body
via the medial olivocochlear bundle.
The cochlear duct is almost as complex on its own as the ear itself. It is bounded on its three sides by the basilar membrane
, the stria vascularis
, and Reissner's membrane
. Stria vascularis is a rich bed of capillaries and secretory cells; reissner's membrane is a thin membrane that just separates endolymph from perilymph; and the basilar membrane is a mechanically somewhat stiff membrane, supporting the receptor organ for hearing, the organ of Corti
, and determines the mechanical wave propagration properties of the cochlear system.
, which moves in response to the vibrations coming from the middle ear via the oval window. As the fluid moves, the cochlear partition (basilar membrane and organ of Corti) moves; thousands of hair cell
s sense the motion via their cilia, and convert that motion to electrical signals that are communicated via neurotransmitters to many thousands of nerve cells. These primary auditory neurons transform the signals into electrochemical impulses known as action potentials, which travel along the auditory nerve to structures in the brainstem for further processing.
– to match the soundwave travelling through air to that travelling in the fluid–membrane system.
At the base of the cochlea, each scala ends in a membranous portal that faces the middle ear cavity: The scala vestibuli
ends at the oval window
, where the footplate of the stapes sits. The footplate vibrates when the pressure is transmitted via the ossicular chain. The wave in the perilymph moves away from the footplate and towards the helicotrema
. Since those fluid waves move the cochlear partition that separates the scalae up and down, the waves have a corresponding symmetric part in perilymph of the scala tympani, which ends at the round window, bulging out when the oval window bulges in.
The perilymph in scala vestibuli and the endolymph
in scala media act mechanically as a single duct, being kept apart only by the very thin Reissner's membrane
.
The vibrations of the endolymph in the scala media displace the basilar membrane in a pattern that peaks a distance from the oval window depending upon the soundwave frequency. The organ of Corti vibrates due to outer hair cells further amplifying these vibrations. Inner hair cells are then displaced by the vibrations in the fluid, and depolarise by an influx of K+ via their tip-link-connected channels, and send their signals via neurotransmitter to the primary auditory neurons of the spiral ganglion
.
The hair cells in the organ of Corti are tuned to certain sound frequencies by way of their location in the cochlea, due to the degree of stiffness in the basilar membrane. This stiffness is due to, among other things, the thickness and width of the basilar membrane, which along the length of the cochlea is stiffest nearest its beginning at the oval window, where the stapes introduces the vibrations coming from the eardrum. Since its stiffness is high there, it allows only high-frequency vibrations to move the basilar membrane, and thus the hair cells. The farther a wave travels towards the cochlea's apex (the helicotrema), the less stiff the basilar membrane is; thus lower frequencies travel down the tube, and the less-stiff membrane is moved most easily by them where the reduced stiffness allows: that is, as the basilar membrane gets less and less stiff, waves slow down and it responds better to lower frequencies. In addition, in mammals, the cochlea is coiled, which has been shown to enhance low-frequency vibrations as they travel through the fluid-filled coil. This spatial arrangement of sound reception is referred to as tonotopy
.
For very low frequencies (below 20 Hz), the waves propagate along the complete route of the cochlea – differentially up scala vestibuli and scala tympani all the way to the helicotrema. Frequencies this low still activate the organ of Corti to some extent, but are too low to elicit the perception of a pitch. Higher frequencies do not propagate to the helicotrema, due to the stiffness-mediated tonotopy.
A very strong movement of the basilar membrane due to very loud noise may cause hair cells to die. This is a common cause of partial hearing loss and is the reason why users of firearms or heavy machinery often wear earmuffs or earplug
s.
on their outer membranes; it generates additional movement that couples back to the fluid–membrane wave. This "active amplifier" is essential in the ear's ability to amplify weak sounds.
The active amplifier also leads to the phenomenon of soundwave vibrations being emitted from the cochlea back into the ear canal (otoacoustic emissions).
, since they are present when the cochlea is working well, and less so when it is suffering from loss of OHC activity.
s. In birds and in other non-mammalian vertebrate
s, the compartment containing the sensory cells for hearing is occasionally also called “cochlea,” despite not being coiled up. Instead, it forms a blind-ended tube, also called the cochlear duct. This difference apparently evolved in parallel with the differences in frequency range of hearing and in frequency resolution between mammals and non-mammalian vertebrates. Most bird species do not hear above 4–5 kHz, the currently known maximum being ~ 11 kHz in the barn owl. Some marine mammals hear up to 200 kHz. The superior frequency resolution in mammals is due to their unique mechanism of pre-amplification of sound by active cell-body vibrations of outer hair cells. A long coiled compartment, rather than a short and straight one, provides more space for mapping pitches, so is therefore better adapted to the highly derived functions in mammalian hearing.
As the study of the cochlea should fundamentally be focused upon the level of hair cells, it is important to note the anatomical and physiological differences between the hair cells of various species. In birds, for instance, instead of outer and inner hair cells, there are tall and short hair cells. There are several similarities of note in regard to this comparative data. For one, the tall hair cell is very similar in function to that of the inner hair cell, and the short hair cell is very similar in function to that of the outer hair cell. One unavoidable difference, however, is that while all hair cells are attached to a tectorial membrane in birds, only the outer hair cells are attached to the tectorial membrane in mammals.
created an electronic chip
that can quickly analyze a very large range of radio frequencies
while using only a fraction of the power needed for existing technologies; its design specifically mimics a cochlea.
Inner ear
The inner ear is the innermost part of the vertebrate ear. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts:...
. It is a spiral-shaped cavity in the bony labyrinth
Bony labyrinth
The Bony labyrinth or osseous labyrinth consists of three parts: the vestibule, semicircular canals, and cochlea. These are cavities hollowed out of the substance of the bone, and lined by periosteum; they contain a clear fluid, the perilymph, in which the membranous labyrinth is situated....
, making 2.5 turns around its axis, the modiolus
Modiolus (cochlea)
The modiolus is a conical shaped central axis in the cochlea. It consists of spongy bone and the cochlea turns approximately 2.5 times around it. The spiral ganglion is situated inside it.-External links:...
.
A core component of the cochlea is the Organ of Corti
Organ of Corti
The organ of Corti is the organ in the inner ear of mammals that contains auditory sensory cells, or "hair cells."The organ was named after the Italian anatomist Marquis Alfonso Giacomo Gaspare Corti , who conducted microscopic research of the mammaliean auditory system.-Structure and function:The...
, the sensory organ of hearing
Hearing (sense)
Hearing is the ability to perceive sound by detecting vibrations through an organ such as the ear. It is one of the traditional five senses...
, which is distributed along the partition separating fluid chambers in the coiled tapered tube of the cochlea.
The name is from the Latin for snail shell, which is from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
κοχλίας kokhlias ("snail, screw"), from κόχλος kokhlos ("spiral shell") in reference to its coiled shape; the cochlea is coiled in most mammals, monotreme
Monotreme
Monotremes are mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals...
s being the exceptions.
Anatomy
Structures
The cochlea is a spiralled, hollow, conical chamber of bone, in which waves propagate from the base (near the middle ear and the oval window) to the apex (the top or center of the spiral). Its structures include:- Three scalae or chambers:
- the scala vestibuliScala vestibuliScala vestibuli is a perilymph-filled cavity inside the cochlea of the inner ear that conducts sound vibrations to the scala media.It is separated from the scala media by Reissner's membrane and extends from the vestibule of the ear to the helicotrema where it joins scala tympani.-External links:* ...
(containing perilymphPerilymphPerilymph is an extracellular fluid located within the cochlea in two of its three compartments: the scala tympani and scala vestibuli. The ionic composition of perilymph is comparable to that of plasma and cerebrospinal fluid...
), which lies superior to the cochlear duct and abuts the oval windowOval windowThe oval window is a membrane-covered opening which leads from the middle ear to the vestibule of the inner ear.Vibrations that come into contact with the tympanic membrane travel through the three ossicles and into the inner ear... - the scala tympaniScala tympaniScala tympani is one of the perilymph-filled cavities in the cochlear labyrinth of the human ear. It is separated from the scala media by the basilar membrane, and it extends from the round window to the helicotrema, where it continues as scala vestibuli....
(containing perilymphPerilymphPerilymph is an extracellular fluid located within the cochlea in two of its three compartments: the scala tympani and scala vestibuli. The ionic composition of perilymph is comparable to that of plasma and cerebrospinal fluid...
), which lies inferior to the scala media and terminates at the round windowRound windowThe round window is one of the two openings into the inner ear. It is closed off from the middle ear by the round window membrane, which vibrates with opposite phase to vibrations entering the inner ear through the oval window... - the scala mediaScala mediaThe cochlear duct is an endolymph filled cavity inside the cochlea, located in between the scala tympani and the scala vestibuli, separated by the basilar membrane and Reissner's membrane respectively....
(containing endolymphEndolymphEndolymph is the fluid contained in the membranous labyrinth of the inner ear. It is also called Scarpa's fluid, after Antonio Scarpa.-Composition:...
), or cochlear duct, a region of high potassium ion concentration that the cilia of the hair cells project into
- the scala vestibuli
- The helicotremaHelicotremaThe helicotrema is the part of the cochlear labyrinth where the scala tympani and the scala vestibuli meet. It is the main component of the cochlear apex. The hair cells in this area best detect low frequency sounds.-External links:* at Allegheny University of the Health Sciences* at IUPUI...
, the location where the scala tympani and the scala vestibuli merge, at the apex of the cochlea - Reissner's membraneReissner's membraneReissner's membrane is a membrane inside the cochlea of the inner ear. It separates scala media from scala vestibuli. Together with the basilar membrane it creates a compartment in the cochlea filled with endolymph, which is important for the function of the organ of Corti...
, which separates the scala vestibuli from the scala media - The basilar membraneBasilar membraneThe basilar membrane within the cochlea of the inner ear is a stiff structural element that separates two liquid-filled tubes that run along the coil of the cochlea, the scala media and the scala tympani .-Function:...
, a main structural element that separates the scala media from the scala tympani and determines the mechanical wave propagation properties of the cochlear partition - The Organ of CortiOrgan of CortiThe organ of Corti is the organ in the inner ear of mammals that contains auditory sensory cells, or "hair cells."The organ was named after the Italian anatomist Marquis Alfonso Giacomo Gaspare Corti , who conducted microscopic research of the mammaliean auditory system.-Structure and function:The...
, the sensory epithelium, a cellular layer on the basilar membrane, in which sensory hair cells are powered by the potential difference between the perilymph and the endolymph - hair cells, sensory cells in the Organ of Corti, topped with hair-like structures called stereocilia
Detailed anatomy
The walls of the hollow cochlea are made of bone, with a thin, delicate lining of epithelial tissue. This coiled tube is divided through most of its length by an inner membranous partition. Two fluid-filled outer spaces (scalae) are formed by this dividing membrane. The fluid in both of these ouiding membrane. This continuation at the helicotrema allows fluid being pushed into the scala vestibuli by the oval window to move back out via movement in scala tympani and deflection of the round window; since the fluid is nearly incompressible and the bony walls are rigid, it is essential for the conserved fluid volume to exit somewhere.The lengthwise partition that divides most of the cochlea is itself a fluid-filled tube, the third scala. This central column is called the scala media
Scala media
The cochlear duct is an endolymph filled cavity inside the cochlea, located in between the scala tympani and the scala vestibuli, separated by the basilar membrane and Reissner's membrane respectively....
, or cochlear duct. Its fluid, endolymph
Endolymph
Endolymph is the fluid contained in the membranous labyrinth of the inner ear. It is also called Scarpa's fluid, after Antonio Scarpa.-Composition:...
, also contains electrolytes and proteins, but is chemically quite different from perilymph. Whereas the perilymph is rich in sodium ions, the endolymph is rich in potassium ions, which produces an ionic, electrical potential.
The hair cells are arranged in four rows in the organ of Corti
Organ of Corti
The organ of Corti is the organ in the inner ear of mammals that contains auditory sensory cells, or "hair cells."The organ was named after the Italian anatomist Marquis Alfonso Giacomo Gaspare Corti , who conducted microscopic research of the mammaliean auditory system.-Structure and function:The...
along the entire length of the cochlear coil. Three rows consist of outer hair cells (OHCs) and one row consists of inner hair cells (IHCs). The inner hair cells provide the main neural output of the cochlea. The outer hair cells, instead, mainly receive neural input from the brain, which influences their motility as part of the cochlea's mechanical pre-amplifier. The input to the OHC is from the olivary body
Olivary body
In anatomy, the olivary bodies or simply olives are a pair of prominent oval structures in the medulla oblongata, the lower portion of the brainstem...
via the medial olivocochlear bundle.
The cochlear duct is almost as complex on its own as the ear itself. It is bounded on its three sides by the basilar membrane
Basilar membrane
The basilar membrane within the cochlea of the inner ear is a stiff structural element that separates two liquid-filled tubes that run along the coil of the cochlea, the scala media and the scala tympani .-Function:...
, the stria vascularis
Stria vascularis
The upper portion of the spiral ligament contains numerous capillary loops and small blood vessels, and is termed the stria vascularis. It produces endolymph for the scala media, one of the three fluid-filled compartments of the cochlea...
, and Reissner's membrane
Reissner's membrane
Reissner's membrane is a membrane inside the cochlea of the inner ear. It separates scala media from scala vestibuli. Together with the basilar membrane it creates a compartment in the cochlea filled with endolymph, which is important for the function of the organ of Corti...
. Stria vascularis is a rich bed of capillaries and secretory cells; reissner's membrane is a thin membrane that just separates endolymph from perilymph; and the basilar membrane is a mechanically somewhat stiff membrane, supporting the receptor organ for hearing, the organ of Corti
Organ of Corti
The organ of Corti is the organ in the inner ear of mammals that contains auditory sensory cells, or "hair cells."The organ was named after the Italian anatomist Marquis Alfonso Giacomo Gaspare Corti , who conducted microscopic research of the mammaliean auditory system.-Structure and function:The...
, and determines the mechanical wave propagration properties of the cochlear system.
Summary
The cochlea is filled with a watery liquid, the perilymphPerilymph
Perilymph is an extracellular fluid located within the cochlea in two of its three compartments: the scala tympani and scala vestibuli. The ionic composition of perilymph is comparable to that of plasma and cerebrospinal fluid...
, which moves in response to the vibrations coming from the middle ear via the oval window. As the fluid moves, the cochlear partition (basilar membrane and organ of Corti) moves; thousands of hair cell
Hair cell
Hair cells are the sensory receptors of both the auditory system and the vestibular system in all vertebrates. In mammals, the auditory hair cells are located within the organ of Corti on a thin basilar membrane in the cochlea of the inner ear...
s sense the motion via their cilia, and convert that motion to electrical signals that are communicated via neurotransmitters to many thousands of nerve cells. These primary auditory neurons transform the signals into electrochemical impulses known as action potentials, which travel along the auditory nerve to structures in the brainstem for further processing.
Detailed events
The stapes (stirrup) ossicle bone of the middle ear transmits vibrations to the fenestra ovalis (oval window) on the outside of the cochlea, which vibrates the perilymph in the scala vestibuli (upper chamber of the cochlea). The ossicles are essential for efficient coupling of sound waves into the cochlea, since the cochlea environment is a fluid–membrane system, and it takes more pressure to move sound through fluid–membrane waves than it does through air; a pressure increase is achieved by the area ratio of the tympanic membrane to the oval window, resulting in a pressure gain of about 20× from the original sound wave pressure in air. This gain is a form of impedance matchingImpedance matching
In electronics, impedance matching is the practice of designing the input impedance of an electrical load to maximize the power transfer and/or minimize reflections from the load....
– to match the soundwave travelling through air to that travelling in the fluid–membrane system.
At the base of the cochlea, each scala ends in a membranous portal that faces the middle ear cavity: The scala vestibuli
Scala vestibuli
Scala vestibuli is a perilymph-filled cavity inside the cochlea of the inner ear that conducts sound vibrations to the scala media.It is separated from the scala media by Reissner's membrane and extends from the vestibule of the ear to the helicotrema where it joins scala tympani.-External links:* ...
ends at the oval window
Oval window
The oval window is a membrane-covered opening which leads from the middle ear to the vestibule of the inner ear.Vibrations that come into contact with the tympanic membrane travel through the three ossicles and into the inner ear...
, where the footplate of the stapes sits. The footplate vibrates when the pressure is transmitted via the ossicular chain. The wave in the perilymph moves away from the footplate and towards the helicotrema
Helicotrema
The helicotrema is the part of the cochlear labyrinth where the scala tympani and the scala vestibuli meet. It is the main component of the cochlear apex. The hair cells in this area best detect low frequency sounds.-External links:* at Allegheny University of the Health Sciences* at IUPUI...
. Since those fluid waves move the cochlear partition that separates the scalae up and down, the waves have a corresponding symmetric part in perilymph of the scala tympani, which ends at the round window, bulging out when the oval window bulges in.
The perilymph in scala vestibuli and the endolymph
Endolymph
Endolymph is the fluid contained in the membranous labyrinth of the inner ear. It is also called Scarpa's fluid, after Antonio Scarpa.-Composition:...
in scala media act mechanically as a single duct, being kept apart only by the very thin Reissner's membrane
Reissner's membrane
Reissner's membrane is a membrane inside the cochlea of the inner ear. It separates scala media from scala vestibuli. Together with the basilar membrane it creates a compartment in the cochlea filled with endolymph, which is important for the function of the organ of Corti...
.
The vibrations of the endolymph in the scala media displace the basilar membrane in a pattern that peaks a distance from the oval window depending upon the soundwave frequency. The organ of Corti vibrates due to outer hair cells further amplifying these vibrations. Inner hair cells are then displaced by the vibrations in the fluid, and depolarise by an influx of K+ via their tip-link-connected channels, and send their signals via neurotransmitter to the primary auditory neurons of the spiral ganglion
Spiral ganglion
The spiral ganglion is the group of nerve cells that serve the sense of hearing by sending a representation of sound from the cochlea to the brain...
.
The hair cells in the organ of Corti are tuned to certain sound frequencies by way of their location in the cochlea, due to the degree of stiffness in the basilar membrane. This stiffness is due to, among other things, the thickness and width of the basilar membrane, which along the length of the cochlea is stiffest nearest its beginning at the oval window, where the stapes introduces the vibrations coming from the eardrum. Since its stiffness is high there, it allows only high-frequency vibrations to move the basilar membrane, and thus the hair cells. The farther a wave travels towards the cochlea's apex (the helicotrema), the less stiff the basilar membrane is; thus lower frequencies travel down the tube, and the less-stiff membrane is moved most easily by them where the reduced stiffness allows: that is, as the basilar membrane gets less and less stiff, waves slow down and it responds better to lower frequencies. In addition, in mammals, the cochlea is coiled, which has been shown to enhance low-frequency vibrations as they travel through the fluid-filled coil. This spatial arrangement of sound reception is referred to as tonotopy
Tonotopy
In physiology, tonotopy is the spatial arrangement of where sounds of different frequency are processed in the brain. Tones close to each other in terms of frequency are represented in topologically neighbouring regions in the brain...
.
For very low frequencies (below 20 Hz), the waves propagate along the complete route of the cochlea – differentially up scala vestibuli and scala tympani all the way to the helicotrema. Frequencies this low still activate the organ of Corti to some extent, but are too low to elicit the perception of a pitch. Higher frequencies do not propagate to the helicotrema, due to the stiffness-mediated tonotopy.
A very strong movement of the basilar membrane due to very loud noise may cause hair cells to die. This is a common cause of partial hearing loss and is the reason why users of firearms or heavy machinery often wear earmuffs or earplug
Earplug
An earplug is a device that is meant to be inserted in the ear canal to protect the wearer's ears from loud noises or the intrusion of water, foreign bodies, dust or excessive wind.-Protection from water:...
s.
Amplification by the hair cells
Not only does the cochlea "receive" sound, it generates and amplifies sound when it is healthy. Where the organism needs a mechanism to hear very faint sounds, the cochlea amplifies by the reverse transducer of the OHCs, converting electrical signals back to mechanical in a possitive-feedback configuration. The OHCs have a protein motor called prestinPrestin
Prestin is a protein that in humans is encoded by the SLC26A5 gene.Prestin is the motor protein of the outer hair cells of the inner ear of the mammalian cochlea. It is highly expressed in the outer hair cells, and is not expressed in the nonmotile inner hair cells...
on their outer membranes; it generates additional movement that couples back to the fluid–membrane wave. This "active amplifier" is essential in the ear's ability to amplify weak sounds.
The active amplifier also leads to the phenomenon of soundwave vibrations being emitted from the cochlea back into the ear canal (otoacoustic emissions).
Otoacoustic emissions
Otoacoustic emissions are due to a wave exiting the cochlea via the oval window, and propagating back through the middle ear to the eardrum, and out the ear canal, where it can be picked up by a microphone. Otoacoustic emissions are important in some types of tests for hearing impairmentHearing impairment
-Definition:Deafness is the inability for the ear to interpret certain or all frequencies of sound.-Environmental Situations:Deafness can be caused by environmental situations such as noise, trauma, or other ear defections...
, since they are present when the cochlea is working well, and less so when it is suffering from loss of OHC activity.
Comparative physiology
The coiled form of cochlea is unique to mammalMammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s. In birds and in other non-mammalian vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s, the compartment containing the sensory cells for hearing is occasionally also called “cochlea,” despite not being coiled up. Instead, it forms a blind-ended tube, also called the cochlear duct. This difference apparently evolved in parallel with the differences in frequency range of hearing and in frequency resolution between mammals and non-mammalian vertebrates. Most bird species do not hear above 4–5 kHz, the currently known maximum being ~ 11 kHz in the barn owl. Some marine mammals hear up to 200 kHz. The superior frequency resolution in mammals is due to their unique mechanism of pre-amplification of sound by active cell-body vibrations of outer hair cells. A long coiled compartment, rather than a short and straight one, provides more space for mapping pitches, so is therefore better adapted to the highly derived functions in mammalian hearing.
As the study of the cochlea should fundamentally be focused upon the level of hair cells, it is important to note the anatomical and physiological differences between the hair cells of various species. In birds, for instance, instead of outer and inner hair cells, there are tall and short hair cells. There are several similarities of note in regard to this comparative data. For one, the tall hair cell is very similar in function to that of the inner hair cell, and the short hair cell is very similar in function to that of the outer hair cell. One unavoidable difference, however, is that while all hair cells are attached to a tectorial membrane in birds, only the outer hair cells are attached to the tectorial membrane in mammals.
Bionics
In 2009, engineers at the Massachusetts Institute of TechnologyMassachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
created an electronic chip
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
that can quickly analyze a very large range of radio frequencies
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
while using only a fraction of the power needed for existing technologies; its design specifically mimics a cochlea.
See also
- LabyrinthLabyrinthIn Greek mythology, the Labyrinth was an elaborate structure designed and built by the legendary artificer Daedalus for King Minos of Crete at Knossos...
- Cochlear implantCochlear implantA cochlear implant is a surgically implanted electronic device that provides a sense of sound to a person who is profoundly deaf or severely hard of hearing...
- Cochlear nerveCochlear nerveThe cochlear nerve is a nerve in the head that carries signals from the cochlea of the inner ear to the brain...
- Cochlear nucleiCochlear nucleiThe cochlear nuclei are two heterogeneous collections of neurons in the mammalian brainstem that receive input from the cochlear nerve, which carry sound information from the cochleae...
- Noise health effectsNoise health effectsNoise health effects are the health consequences of elevated sound levels. Elevated workplace or other noise can cause hearing impairment, hypertension, ischemic heart disease, annoyance and sleep disturbance. Changes in the immune system and birth defects have been attributed to noise exposure...
- Cochlear virus
- Cochlear implosions
External links
- "Promenade 'Round the Cochlea" by R. Pujol, S. Blatrix, T. Pujol et al. at University of MontpellierUniversity of MontpellierThe University of Montpellier was a French university in Montpellier in the Languedoc-Roussillon région of the south of France. Its present-day successor universities are the University of Montpellier 1, Montpellier 2 University and Paul Valéry University, Montpellier III.-History:The university...
- "The Cochlea Homepage", F. Mammano and R. Nobili of the Venetian Institute of Molecular Medicine
- MYSTERIES OF THE COCHLEA Dr. Janez Faganel Memorial Lecture at University Medical Centre Ljubljana