query: where are sound vibrations converted into action potentials

pos: Transduction (physiology) the brain. A change in neurotransmitter release is mediated through a second messenger system. Note that the change in neurotransmitter release is by rods. Because of the change, a change in light intensity causes the response of the rods to be much slower than expected (for a process associated with the nervous system). In the auditory system, sound vibrations (mechanical energy) are transduced into electrical energy by hair cells in the inner ear. Sound vibrations from an object cause vibrations in air molecules, which in turn, vibrate the ear drum. The movement of the eardrum causes the bones of the

pos: Topographic map (neuroanatomy) a discontinuity has been introduced in either the visual field or the retina. The maps in V2 and other extrastriate cortex are second-order representations. The auditory system is the sensory system for hearing in which the brain interprets information from the frequency of sound waves, yielding the perception of tones. Sound waves enter the ear through the auditory canal. These waves arrive at the eardrum where the properties of the waves are transduced into vibrations. The vibrations travel through the bones of the inner ear to the cochlea. In the cochlea, the vibrations are transduced into electrical information through the

pos: Ear tube. The three ossicles transmit sound from the outer ear to the inner ear. The malleus receives vibrations from sound pressure on the eardrum, where it is connected at its longest part (the manubrium or handle) by a ligament. It transmits vibrations to the incus, which in turn transmits the vibrations to the small stapes bone. The wide base of the stapes rests on the oval window. As the stapes vibrates, vibrations are transmitted through the oval window, causing movement of fluid within the cochlea. The round window allows for the fluid within the inner ear to move. As the

pos: Transduction (physiology) the brain. A change in neurotransmitter release is mediated through a second messenger system. Note that the change in neurotransmitter release is by rods. Because of the change, a change in light intensity causes the response of the rods to be much slower than expected (for a process associated with the nervous system). In the auditory system, sound vibrations (mechanical energy) are transduced into electrical energy by hair cells in the inner ear. Sound vibrations from an object cause vibrations in air molecules, which in turn, vibrate the ear drum. The movement of the eardrum causes the bones of the

neg: Sensorineural hearing loss and the IHCs is to function as sensory receptors. The main function of the IHCs is to transmit sound information via afferent neurons. They do this by transducing mechanical movements or signals into neural activity. When stimulated, the stereocilia on the IHCs move, causing a flow of electric current to pass through the hair cells. This electric current creates action potentials within the connected afferent neurons. OHCs are different in that they actually contribute to the active mechanism of the cochlea. They do this by receiving mechanical signals or vibrations along the basilar membrane, and transducing them into electrochemical signals.

neg: Somatosensory system vibration (10–50 Hz) and light touch. They are located in the dermal papillae; due to their reactivity they are primarily located in fingertips and lips. They respond in quick action potentials, unlike Merkel. They are responsible for the ability to read Braille and feel gentle stimuli. Lamellar corpuscles determine gross touch and distinguish rough and soft substances. They react in quick action potentials, especially to vibrations around 250 Hz (even up to centimeters away). They are the most sensitive to vibrations, and have large receptor fields. Pacinian reacts only to sudden stimuli so pressures like clothes that are always compressing

neg: Hearing cochlea, and low at the apex. Basilar membrane motion causes depolarization of the hair cells, specialized auditory receptors located within the organ of Corti. While the hair cells do not produce action potentials themselves, they release neurotransmitter at synapses with the fibers of the auditory nerve, which does produce action potentials. In this way, the patterns of oscillations on the basilar membrane are converted to spatiotemporal patterns of firings which transmit information about the sound to the brainstem. The sound information from the cochlea travels via the auditory nerve to the cochlear nucleus in the brainstem. From there, the signals

neg: Computational auditory scene analysis auditory system, it is necessary to view parts of the biological auditory system in terms of known physical models. Consisting of three areas, the outer, middle and inner ear, the auditory periphery acts as a complex transducer that converts sound vibrations into action potentials in the auditory nerve. The outer ear consists of the external ear, ear canal and the ear drum. The outer ear, like an acoustic funnel, helps locating the sound source. The ear canal acts as a resonant tube (like an organ pipe) to amplify frequencies between 2–5.5 kHz with a maximum amplification of about 11 dB

neg: Hair cell action potential. Instead, the influx of positive ions from the endolymph in the scala media depolarizes the cell, resulting in a receptor potential. This receptor potential opens voltage gated calcium channels; calcium ions then enter the cell and trigger the release of neurotransmitters at the basal end of the cell. The neurotransmitters diffuse across the narrow space between the hair cell and a nerve terminal, where they then bind to receptors and thus trigger action potentials in the nerve. In this way, the mechanical sound signal is converted into an electrical nerve signal. Repolarization of hair cells is done in

neg: Tactile corpuscle vibrations, but for the same reasons, they are limited in their detection because they can only signal that something is touching the skin. Any physical deformation of the corpuscle will cause sodium ions to enter it, creating an action potential in the corpuscle's nerve fiber. Since they are rapidly adapting or phasic, the action potentials generated quickly decrease and eventually cease (this is the reason one stops "feeling" one's clothes). If the stimulus is removed, the corpuscle regains its shape and while doing so (i.e.: while physically reforming) causes another volley of action potentials to be generated. Tactile corpuscle Tactile

neg: Electron scattering due to energy being converted into vibrations which can be interpreted as heat, waves (sound), or vibrations between constituent particles of either collision party. Particles "may" also split apart, further energy can be converted into breaking the chemical bonds between components. Furthermore, momentum is conserved in both elastic and inelastic scattering. The other two results are reactions (when the structure of the interacting particles is changed producing two or more (generally complex particles)), and that new particles that are not constituent elementary particles of the interacting particles are created. Compton scattering, so named for Arthur Compton who first observed the

neg: Neural coding can travel down nerve fibers. Sensory neurons change their activities by firing sequences of action potentials in various temporal patterns, with the presence of external sensory stimuli, such as light, sound, taste, smell and touch. It is known that information about the stimulus is encoded in this pattern of action potentials and transmitted into and around the brain. Although action potentials can vary somewhat in duration, amplitude and shape, they are typically treated as identical stereotyped events in neural coding studies. If the brief duration of an action potential (about 1ms) is ignored, an action potential sequence, or spike train,

neg: Neural decoding brains are constantly making decisions about what object they are looking at, where they need to move their eyes next, and what they find to be the most salient aspects of the input stimulus. As these images hit the back of the retina, these stimuli are converted from varying wavelengths to a series of neural spikes called action potentials. These pattern of action potentials are different for different objects and different colors; we therefore say that the neurons are encoding objects and colors by varying their spike rates or temporal pattern. Now, if someone were to probe the brain by

neg: Action potential either of which may stimulate subsequent neuron(s) into firing an action potential. For illustration, in the human ear, hair cells convert the incoming sound into the opening and closing of mechanically gated ion channels, which may cause neurotransmitter molecules to be released. In similar manner, in the human retina, the initial photoreceptor cells and the next layer of cells (comprising bipolar cells and horizontal cells) do not produce action potentials; only some amacrine cells and the third layer, the ganglion cells, produce action potentials, which then travel up the optic nerve. In sensory neurons, action potentials result from an external

neg: Infrasonic burglar alarm Infrasonic burglar alarm The infrasonic burglar alarm reacts to shock waves in the air that are produced by a break-in. When an intruder tries to break a window or force open a door or a window, the resultant air pressure variations (or shock waves) produce sound vibrations in the air, from 0.1 – 50 Hz. These low frequency sound vibrations are captured by a very sensitive receiver in the alarm and converted into electronic signals. These signals are then passed through a pre-programmed electronic filtering system for analysis and when found positive, activate the alarm siren immediately; thus dissuading the

neg: Action potential potential is independent of the amount of current that produced it. In other words, larger currents do not create larger action potentials. Therefore, action potentials are said to be all-or-none signals, since either they occur fully or they do not occur at all. This is in contrast to receptor potentials, whose amplitudes are dependent on the intensity of a stimulus. In both cases, the frequency of action potentials is correlated with the intensity of a stimulus. In sensory neurons, an external signal such as pressure, temperature, light, or sound is coupled with the opening and closing of ion channels, which

neg: Transduction (physiology) middle ear (the ossicles) to vibrate. These vibrations then pass into the cochlea, the organ of hearing. Within the cochlea, the hair cells on the sensory epithelium of the organ of Corti bend and cause movement of the basilar membrane. The membrane undulates in different sized waves according to the frequency of the sound. Hair cells are then able to convert this movement (mechanical energy) into electrical signals (graded receptor potentials) which travel along auditory nerves to hearing centres in the brain. In the olfactory system, odorant molecules in the mucus bind to G-protein receptors on olfactory cells. The G-protein

neg: Binaural unmasking brain, before being subtracted one from the other. In effect, the coincidence detectors are replaced with neurons that are excited by action potentials from one ear, but inhibited by action potentials from the other. However, EC theory is not generally framed in such explicit neurological terms, and no suitable neural substrate has been identified in the brain. Nonetheless, EC theory has proved a very popular modelling framework, and has fared well in direct comparison with cross-correlation models in psychoacoustic experiments The ear filters incoming sound into different frequencies: a given place in the cochlea, and a given auditory nerve fibre,

neg: Afterhyperpolarization Afterhyperpolarization Afterhyperpolarization, or AHP, is the hyperpolarizing phase of a neuron's action potential where the cell's membrane potential falls below the normal resting potential. This is also commonly referred to as an action potential's undershoot phase. AHPs have been segregated into "fast", "medium", and "slow" components that appear to have distinct ionic mechanisms and durations. While fast and medium AHPs can be generated by single action potentials, slow AHPs generally develop only during trains of multiple action potentials. During single action potentials, transient depolarization of the membrane opens more voltage-gated K channels than are open in the resting state, many

neg: Cochlea Corti, and determines the mechanical wave propagation properties of the cochlear system. The cochlea is filled with a watery liquid, the perilymph, 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 cells sense the motion via their stereocilia, 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

neg: Cochlear nucleus of the cochlear nuclei it is first necessary to understand the way sound information is represented by the fibers of the auditory nerve. Briefly, there are around 30,000 auditory nerve fibres in each of the two auditory nerves. Each fiber is an axon of a spiral ganglion cell that represents a particular frequency of sound, and a particular range of loudness. Information in each nerve fibre is represented by the rate of action potentials as well as the particular timing of individual action potentials. The particular physiology and morphology of each cochlear nucleus cell type enhances different aspects of sound

neg: Whale no major competitors. Odontocetes are known as toothed whales; they have teeth and only one blowhole. They rely on their well-developed sonar to find their way in the water. Toothed whales send out ultrasonic clicks using the melon. Sound waves travel through the water. Upon striking an object in the water, the sound waves bounce back at the whale. These vibrations are received through fatty tissues in the jaw, which is then rerouted into the ear-bone and into the brain where the vibrations are interpreted. All toothed whales are opportunistic, meaning they will eat anything they can fit in their

neg: Law of specific nerve energies by optic nerve, and the auditory experience from sound coming into the ear, or from electrical stimulation of the cochlea, arises from some different, special quality of the energy carried by the auditory nerve. In 1912, Lord Edgar Douglas Adrian showed that all neurons carry the same energy, electrical energy in the form of action potentials. That means that the quality of an experience depends on the part of the brain to which nerves deliver their action potentials (e.g., light from nerves arriving at the visual cortex and sound from nerves arriving at the auditory cortex). In 1945, Roger Sperry

neg: Tin can telephone as to avoid coming into contact with the object around which the signal is to be directed. Tin can telephone A tin can telephone is a type of acoustic (non-electrical) speech-transmitting device made up of two tin cans, paper cups or similarly shaped items attached to either end of a taut string or wire. It is a form of mechanical telephony, where sound is converted into and then conveyed by vibrations along a liquid or solid medium, and then reconverted back to sound. Before the invention of the electromagnetic telephone, there were mechanical acoustic devices for transmitting spoken words and

neg: Sensory neuron of animal species. Sensory neuron Sensory neurons also known as afferent neurons are neurons that convert a specific type of stimulus, via their receptors, into action potentials or graded potentials. This process is called sensory transduction. The cell bodies of the sensory neurons are located in the dorsal ganglia of the spinal cord. This sensory information travels along afferent nerve fibers in an afferent or sensory nerve, to the brain via the spinal cord. The stimulus can come from "extoreceptors" outside the body, for example light and sound, or from "interoreceptors" inside the body, for example blood pressure or the

neg: Sensory neuron Sensory neuron Sensory neurons also known as afferent neurons are neurons that convert a specific type of stimulus, via their receptors, into action potentials or graded potentials. This process is called sensory transduction. The cell bodies of the sensory neurons are located in the dorsal ganglia of the spinal cord. This sensory information travels along afferent nerve fibers in an afferent or sensory nerve, to the brain via the spinal cord. The stimulus can come from "extoreceptors" outside the body, for example light and sound, or from "interoreceptors" inside the body, for example blood pressure or the sense of body

neg: Psychoacoustics sensory and perceptual event; in other words, when a person hears something, that something arrives at the ear as a mechanical sound wave traveling through the air, but within the ear it is transformed into neural action potentials. The outer hair cells (OHC) of a mammalian cochlea give rise to an enhanced sensitivity and better frequency resolution of the mechanical response of the cochlear partition. These nerve pulses then travel to the brain where they are perceived. Hence, in many problems in acoustics, such as for audio processing, it is advantageous to take into account not just the mechanics of

neg: Diaphragm (acoustics) Diaphragm (acoustics) In the field of acoustics, a diaphragm is a transducer intended to inter-convert mechanical vibrations to sounds, or vice versa. It is commonly constructed of a thin membrane or sheet of various materials, suspended at its edges. The varying air pressure of sound waves imparts mechanical vibrations to the diaphragm which can then be converted to some other type of signal; examples of this type of diaphragm are found in microphones and the human eardrum. Conversely a diaphragm vibrated by a source of energy beats against the air, creating sound waves. Examples of this type of diaphragm are

neg: Action potential potential), action potentials are generated anew along excitable stretches of membrane and propagate without decay. Myelinated sections of axons are not excitable and do not produce action potentials and the signal is propagated passively as electrotonic potential. Regularly spaced unmyelinated patches, called the nodes of Ranvier, generate action potentials to boost the signal. Known as saltatory conduction, this type of signal propagation provides a favorable tradeoff of signal velocity and axon diameter. Depolarization of axon terminals, in general, triggers the release of neurotransmitter into the synaptic cleft. In addition, backpropagating action potentials have been recorded in the dendrites of pyramidal

neg: Diathermy propelled through the tissues, are converted into heat. This type of diathermy is especially useful in the delivery of heat to selected musculatures and structures because there is a difference in the sensitivity of various fibers to the acoustic vibrations; some are more absorptive and some are more reflective. For example, in subcutaneous fat, relatively little energy is converted into heat, but in muscle tissues there is a much higher rate of conversion to heat. The therapeutic ultrasound apparatus generates a high-frequency alternating current, which is then converted into acoustic vibrations. The apparatus is moved slowly across the surface of

neg: Postsynaptic potential Postsynaptic potential Postsynaptic potentials are changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Postsynaptic potentials are graded potentials, and should not be confused with action potentials although their function is to initiate or inhibit action potentials. They are caused by the presynaptic neuron releasing neurotransmitters from the terminal bouton at the end of an axon into the synaptic cleft. The neurotransmitters bind to receptors on the postsynaptic terminal, which may be a neuron or a muscle cell in the case of a neuromuscular junction. These are collectively referred to as postsynaptic receptors, since they are

neg: Inferior temporal gyrus the eye. This chemical energy is then converted into action potentials that are transferred through the optic nerve and across the optic chiasm, where it is first processed by the lateral geniculate nucleus of the thalamus. From there the information is sent to the primary visual cortex, region V1. It then travels from the visual areas in the occipital lobe to the parietal and temporal lobes via two distinct anatomical streams. These two cortical visual systems were classified by Ungerleider and Mishkin (1982, see two-streams hypothesis). One stream travels ventrally to the inferior temporal cortex (from V1 to V2 then

neg: Tin can telephone Tin can telephone A tin can telephone is a type of acoustic (non-electrical) speech-transmitting device made up of two tin cans, paper cups or similarly shaped items attached to either end of a taut string or wire. It is a form of mechanical telephony, where sound is converted into and then conveyed by vibrations along a liquid or solid medium, and then reconverted back to sound. Before the invention of the electromagnetic telephone, there were mechanical acoustic devices for transmitting spoken words and music over a distance greater than that of normal speech. The very earliest mechanical telephones were based

neg: Saltatory conduction Saltatory conduction Saltatory conduction (from the Latin "saltare", to hop or leap) is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials. The uninsulated nodes of Ranvier are the only places along the axon where ions are exchanged across the axon membrane, regenerating the action potential between regions of the axon that are insulated by myelin, unlike electrical conduction in a simple circuit. Myelinated axons only allow action potentials to occur at the unmyelinated nodes of Ranvier that occur between the myelinated internodes. It is

neg: Seismic communication structure which may detect seismic waves. The sensory organs are generically known as somatosensory mechanoreceptors. In insects these sensors are known as campaniform sensillae located near the joints, the subgenual organ in the tibia and Johnston's organ located in the antennae. Arachnids use slit sense organ. In vertebrate animals the sensors are Pacinian corpuscles in placental mammals, similar lamellated corpuscles in marsupials, Herbst corpuscles in birds and a variety of encapsulated or naked nerve endings in other animals. These sensory receivers detect vibrations in the skin and joints, from which they are typically transmitted as nerve impulses (action potentials) to

neg: Scolopidia Scolopidia A scolopidium (historically scolopophore) is the most fundamental unit of a mechanoreceptor organ in insects. It is a composition of three cells, a scolopale cap cell which caps the scolopale cell, and a bipolar sensory nerve cell. Scolopidia are sensitive to things like sound (vibrations of the air) or substrate vibrations (feeling vibrations on a leaf, for instance) depending on the structure of the overall sense organ in which they reside. These organs ultimately convert mechanical vibration into a nerve impulse which is sent on to higher ganglion where the information is combined and/or processed into a resultant behavior.

neg: Neuronal encoding of sound participate in the processing, but one hemisphere tends to play a more significant role than the other. Neuronal encoding of sound The neuronal encoding of sound is the representation of auditory sensation and perception in the nervous system. This article explores the basic physiological principles of sound perception, and traces hearing mechanisms from sound as pressure waves in air to the transduction of these waves into electrical impulses (action potentials) along auditory nerve fibers, and further processing in the brain. The complexities of contemporary neuroscience are continually redefined. Thus what is known now of the auditory system has changed in

neg: Neuronal encoding of sound Neuronal encoding of sound The neuronal encoding of sound is the representation of auditory sensation and perception in the nervous system. This article explores the basic physiological principles of sound perception, and traces hearing mechanisms from sound as pressure waves in air to the transduction of these waves into electrical impulses (action potentials) along auditory nerve fibers, and further processing in the brain. The complexities of contemporary neuroscience are continually redefined. Thus what is known now of the auditory system has changed in the recent times and thus conceivably in the next two years or so, much of this will

neg: Electrotonic potential Electrotonic potential In physiology, electrotonus refers to the passive spread of charge inside a neuron. "Passive" means that voltage-dependent changes in membrane conductance do not contribute. Neurons and other excitable cells produce two types of electrical potential: Electrotonic potentials represent changes to the neuron's membrane potential that do not lead to the generation of new current by action potentials. However, all action potentials are begun by electrotonic potentials depolarizing the membrane above the threshold potential which converts the electrotonic potential into an action potential. Neurons which are small in relation to their length, such as some neurons in the brain,

neg: Binaural fusion of rapidly adjusting tuning properties depending on the context in which sounds are heard. Each eardrum moves one-dimensionally; the auditory brain analyzes and compares movements of both eardrums to extract physical cues and synthesize auditory objects. When stimulation from a sound reaches the ear, the eardrum deflects in a mechanical fashion, and the three middle ear bones (ossicles) transmit the mechanical signal to the cochlea, where hair cells transform the mechanical signal into an electrical signal. The auditory nerve, also called the cochlear nerve, then transmits action potentials to the central auditory nervous system. In binaural fusion, inputs from both

neg: Medical ultrasound Specifically, sound is reflected anywhere where there are acoustic impedance changes in the body: e.g. blood cells in blood plasma, small structures in organs, etc. Some of the reflections return to the transducer. The return of the sound wave to the transducer results in the same process as sending the sound wave, except in reverse. The returned sound wave vibrates the transducer and the transducer turns the vibrations into electrical pulses that travel to the ultrasonic scanner where they are processed and transformed into a digital image. To make an image, the ultrasound scanner must determine two things from each

neg: SoundBite Hearing System or right back teeth. Both components have rechargeable batteries and a charger is included with the system. The BTE microphone captures and processes sound, and wirelessly transmits the sound signals to the ITM device. The ITM receives these signals and converts them into sound vibrations. These subtle sound vibrations travel via the teeth, through bones in the skull, to the functioning inner ear or cochlea, bypassing problems in the outer or middle ear entirely. Although the vibrations are strong enough to be picked up by the cochlea, they are so subtle as to not be felt by the wearer. In

neg: Henry Markram terminals with Elise F. Stanley. As a Minerva Fellow he then went to the Laboratory of Bert Sakmann at the Max Planck Institute, Heidelberg, Germany, where he discovered calcium transients in dendrites evoked by sub-threshold activity, and by single action potentials propagating back into dendrites. He also began studying the connectivity between neurons, describing in great detail how layer 5 pyramidal neurons are interconnected. Some of his work altered the relative timing of single pre- and post-synaptic action potentials to reveal a learning mechanism operating between neurons where the relative timing in the millisecond range affects the coupling strength between

neg: Action potential in turn alter the ionic permeabilities of the membrane and its voltage. These voltage changes can again be excitatory (depolarizing) or inhibitory (hyperpolarizing) and, in some sensory neurons, their combined effects can depolarize the axon hillock enough to provoke action potentials. Some examples in humans include the olfactory receptor neuron and Meissner's corpuscle, which are critical for the sense of smell and touch, respectively. However, not all sensory neurons convert their external signals into action potentials; some do not even have an axon! Instead, they may convert the signal into the release of a neurotransmitter, or into continuous graded potentials,

neg: Myasthenia gravis a thin needle electrode is inserted into different areas of a particular muscle to record the action potentials from several samplings of different individual muscle fibers. Two muscle fibers belonging to the same motor unit are identified, and the temporal variability in their firing patterns is measured. Frequency and proportion of particular abnormal action potential patterns, called "jitter" and "blocking", are diagnostic. Jitter refers to the abnormal variation in the time interval between action potentials of adjacent muscle fibers in the same motor unit. Blocking refers to the failure of nerve impulses to elicit action potentials in adjacent muscle fibers

neg: Electrotonic potential charge or decrease it with negative charge. Electronic potentials that increase the membrane potential are called excitatory postsynaptic potentials (EPSPs). This is because they depolarize the membrane, increasing the likelihood of an action potential. As they sum together they can depolarize the membrane sufficiently to push it above the threshold potential, which will then cause an action potential to occur. EPSPs are often caused by either Na or Ca coming into the cell. Electrotonic potentials which decrease the membrane potential are called inhibitory postsynaptic potentials (IPSPs). They hyperpolarize the membrane and make it harder for a cell to have an

neg: Binaural fusion time difference (ITD). Localization of high frequency sounds is accomplished by analyzing interaural level difference (ILD). Action potentials originate in the hair cells of the cochlea and propagate to the brainstem; both the timing of these action potentials and the signal they transmit provide information to the SOC about the orientation of sound in space. The processing and propagation of action potentials is rapid, and therefore, information about the timing of the sounds that were heard, which is crucial to binaural processing, is conserved. Each eardrum moves in one dimension, and the auditory brain analyzes and compares the movements of

neg: Action potential to fire an action potential at the second or third node. Thus, the safety factor of saltatory conduction is high, allowing transmission to bypass nodes in case of injury. However, action potentials may end prematurely in certain places where the safety factor is low, even in unmyelinated neurons; a common example is the branch point of an axon, where it divides into two axons. Some diseases degrade myelin and impair saltatory conduction, reducing the conduction velocity of action potentials. The most well-known of these is multiple sclerosis, in which the breakdown of myelin impairs coordinated movement. The flow of currents

neg: Lamellar corpuscle corpuscles are larger and fewer in number than Meissner's corpuscle, Merkel cells and Ruffini's corpuscles. The Lamellar corpuscle is approximately oval-cylindrical-shaped and 1 mm in length. The entire corpuscle is wrapped by a layer of connective tissue. Its capsule consists of 20 to 60 concentric lamellae including fibroblasts and fibrous connective tissue (mainly Type IV and Type II collagen network), separated by gelatinous material, more than 92% of which is water. Lamellar corpuscles are rapidly adapting (phasic) receptors that detect gross pressure changes and vibrations in the skin. Any deformation in the corpuscle causes action potentials to be generated by

neg: Membrane potential are sodium (Na) and potassium (K). Both of these are "monovalent" cations that carry a single positive charge. Action potentials can also involve calcium (Ca), which is a "divalent" cation that carries a double positive charge. The chloride anion (Cl) plays a major role in the action potentials of some algae, but plays a negligible role in the action potentials of most animals. Ions cross the cell membrane under two influences: diffusion and electric fields. A simple example wherein two solutions—A and B—are separated by a porous barrier illustrates that diffusion will ensure that they will eventually mix into equal

neg: Phonomotor Phonomotor The phonomotor or "vocal engine" was a device invented by Thomas Edison in 1878 to measure the mechanical force of sound. It converted sound energy or sound power into rotary motion which could drive a machine such as a small saw or drill. It derived from his work on the telephone and phonograph. Sound waves entering a mouthpiece and falling on a diaphragm were conveyed by a piece of rubber tubing and a spring to a pawl, which vibrated against a very fine-toothed ratchet wheel. The diaphragm and mouthpiece were similar to those used on the phonograph. Vibrations caused

neg: Graded potential of the stimulus. Graded potentials that make the membrane potential less negative or more positive, thus making the postsynaptic cell more likely to have an action potential, are called excitatory postsynaptic potentials (EPSPs). Depolarizing local potentials sum together, and if the voltage reaches the threshold potential, an action potential occurs in that cell. EPSPs are caused by the influx of Na or Ca from the extracellular space into the neuron or muscle cell. When the presynaptic neuron has an action potential, Ca enters the axon terminal via voltage-dependent calcium channels and causes exocytosis of synaptic vesicles, causing neurotransmitter to be

neg: Cramp action potentials, which are waves in the electrical charges that extend along neurons. The waves travel to a group of cells in a muscle, letting calcium ions out from the cells' sarcoplasmic reticula (SR), which are storage areas for calcium. The released calcium lets myofibrils contract under the power of energy-carrying adenosine triphosphate (ATP) molecules. Meanwhile, the calcium is quickly pumped back into the SR by fast calcium pumps. Each muscle cell contracts fully; stronger contraction of the whole muscle requires more action potentials on more groups of cells in the muscle. When the action potentials stop, the calcium stops

neg: Tetrode (biology) Tetrode (biology) A tetrode is a type of electrode used in neuroscience for electrophysiological recordings. They are generally used to record the extracellular field potentials from nervous tissue, e.g. the brain. Tetrodes are constructed by bundling together four very small electrodes; each wire is generally less than 30 μm in diameter. Tetrodes are used to classify extra-cellular action potentials into sets generated by the individual neurons, as each channel of the tetrode is usually close enough to a cell such that action potentials emitted by that cell are detected on each of the four channels, but because of the spatial

neg: Tomás Saraceno into the sound properties of spider webs. In collaboration with arachnologists, musicians and sound engineers based in Singapore and elsewhere, Saraceno has harnessed the structural properties of spider silk, transforming the web into a musical instrument. Since spiders do not possess an auditory system, they perceive the world around them with pressure and vibrations that come from their own movement, for example web-plucking. A cobweb is therefore a sensory object, an extension of a spider's body and the vibrations communicated via this practice are used for attraction, hunting and other social interactions. Saraceno has succeeded in amplifying these inaudible vibrations

neg: Soliton model in neuroscience Soliton model in neuroscience The soliton hypothesis in neuroscience is a model that claims to explain how action potentials are initiated and conducted along axons based on a thermodynamic theory of nerve pulse propagation. It proposes that the signals travel along the cell's membrane in the form of certain kinds of solitary sound (or density) pulses that can be modeled as solitons. The model is proposed as an alternative to the Hodgkin–Huxley model in which action potentials: voltage-gated ion channels in the membrane open and allow sodium ions to enter the cell (inward current). The resulting decrease in membrane potential

neg: Dendrite by their active voltage gated conductance, is their ability to send action potentials back into the dendritic arbor. Known as back-propagating action potentials, these signals depolarize the dendritic arbor and provide a crucial component toward synapse modulation and long-term potentiation. Furthermore, a train of back-propagating action potentials artificially generated at the soma can induce a calcium action potential (a dendritic spike) at the dendritic initiation zone in certain types of neurons. Dendrites themselves appear to be capable of plastic changes during the adult life of animals, including invertebrates. Neuronal dendrites have various compartments known as functional units that are able

neg: Phonograph record entered the home. The spring motor was replaced by an electric motor. The old sound box with its needle-linked diaphragm was replaced by an electromagnetic pickup that converted the needle vibrations into an electrical signal. The tone arm now served to conduct a pair of wires, not sound waves, into the cabinet. The exponential horn was replaced by an amplifier and a loudspeaker. Sales of records declined precipitously during the Great Depression of the 1930s. RCA, which purchased the Victor Talking Machine Company in 1929, introduced an inexpensive turntable called the Duo Jr., which was designed to be connected to

neg: Lamellar corpuscle opening pressure-sensitive sodium ion channels in the axon membrane. This allows sodium ions to influx, creating a receptor potential. These corpuscles are especially susceptible to vibrations, which they can sense even centimeters away. Their optimal sensitivity is 250 Hz, and this is the frequency range generated upon fingertips by textures made of features smaller than 1 µm. Lamellar corpuscles cause action potentials when the skin is rapidly indented but not when the pressure is steady, due to the layers of connective tissue that cover the nerve ending. It is thought that they respond to high-velocity changes in joint position. Lamellar

neg: Action potential concentrations. The few ions that do cross are pumped out again by the continuous action of the sodium–potassium pump, which, with other ion transporters, maintains the normal ratio of ion concentrations across the membrane. Calcium cations and chloride anions are involved in a few types of action potentials, such as the cardiac action potential and the action potential in the single-cell alga "Acetabularia", respectively. Although action potentials are generated locally on patches of excitable membrane, the resulting currents can trigger action potentials on neighboring stretches of membrane, precipitating a domino-like propagation. In contrast to passive spread of electric potentials (electrotonic

neg: Antonio Meucci variable electrical conduction in the wire. "Another instrument is also applied to the ears," but he does not say that variable electrical conduction in the wire is to be converted to sound. In the third claim, he claims "a sound conductor which is also an electrical conductor, as a means of communication by sound" which is consistent with acoustic sound vibrations in the wire that somehow get transmitted better if electrical conductors such as a wire or metallic tube are used." Meucci emphasizes that the conductors "for mouth and ears ... must be metallic", but does not explain why this

neg: Plateau potentials Plateau potentials Plateau potentials, caused by persistent inward currents (PICs), are a type of electrical behavior seen in neurons. Plateau potentials are of particular importance to spinal cord motor systems. PICs are set up by the influence of descending monoaminergic reticulospinal pathways. Metabotropic neurotransmitters, via monoaminergic input such as 5-HT and norepinephrine, modulate the activity of dendritic L-type Calcium channels that allow a sustained, positive, inward current into the cell. This leads to a lasting depolarisation. In this state, the cell fires action potentials independent of synaptic input. The PICs can be turned off via the activation of high-frequency inhibitory

neg: Electric piano Electric piano An electric piano is an electric musical instrument which produces sounds when a performer presses the keys of the piano-style musical keyboard. Pressing keys causes mechanical hammers to strike metal strings, metal reeds or wire tines, leading to vibrations which are converted into electrical signals by magnetic pickups, which are then connected to an instrument amplifier and loudspeaker to make a sound loud enough for the performer and audience to hear. Unlike a synthesizer, the electric piano is not an electronic instrument. Instead, it is an electro-mechanical instrument. Some early electric pianos used lengths of wire to produce

neg: Music technology produces sounds when a performer presses the keys of the piano-style musical keyboard. Pressing keys causes mechanical hammers to strike metal strings or tines, leading to vibrations which are converted into electrical signals by magnetic pickups, which are then connected to an instrument amplifier and loudspeaker to make a sound loud enough for the performer and audience to hear. Unlike a synthesizer, the electric piano is not an electronic instrument. Instead, it is an electro-mechanical instrument. Some early electric pianos used lengths of wire to produce the tone, like a traditional piano. Smaller electric pianos used short slivers of steel,

neg: Action potential upward and then equally abruptly shoots back downward, often ending below the resting level, where it remains for some period of time. The shape of the action potential is stereotyped; this means that the rise and fall usually have approximately the same amplitude and time course for all action potentials in a given cell. (Exceptions are discussed later in the article). In most neurons, the entire process takes place in about a thousandth of a second. Many types of neurons emit action potentials constantly at rates of up to 10–100 per second. However, some types are much quieter, and may

neg: Oligodendrocyte progenitor cell in an immature state. White and gray matter OPCs have different resting membrane potentials and ion channel expression. Gray matter lacks voltage-gated sodium channels while white matter does not and produces action potentials. Cells that produce action potentials can receive signals from other neurons. These differences in OPC function depend on their locations. Through maturation, OPCs are produced in the sub-ventricular zone (SVZ). The stem cells in the SVZ generate C cells which produce OPCs that go into the olfactory bulb. The number of oligodendrocytes that are later formed depends on the part of the SVZ they came from. More

neg: Action potential "fires", producing an action potential. The frequency at which a neuron elicits action potentials is often referred to as a firing rate or neural firing rate. Currents produced by the opening of voltage-gated channels in the course of an action potential are typically significantly larger than the initial stimulating current. Thus, the amplitude, duration, and shape of the action potential are determined largely by the properties of the excitable membrane and not the amplitude or duration of the stimulus. This all-or-nothing property of the action potential sets it apart from graded potentials such as receptor potentials, electrotonic potentials, and synaptic

neg: Substantia nigra The GABAergic neurons of the pars reticulata spontaneously fire action potentials. In rats, the frequency of action potentials is roughly 25 Hz. The purpose of these spontaneous action potentials is to inhibit targets of the basal ganglia, and decreases in inhibition are associated with movement. The subthalamic nucleus gives excitatory input that modulates the rate of firing of these spontaneous action potentials. However, lesion of the subthalamic nucleus leads to only a 20% decrease in pars reticulata firing rate, suggesting that the generation of action potentials in the pars reticulata is largely autonomous, as exemplified by the pars reticulata's role

neg: Spike potential Spike potential Spike potentials are one of the action potentials, which occur in electrical activity of smooth muscle contraction in animals. These are true action potentials. In the human gut they occur automatically when the resting membrane potential of the gastrointestinal smooth muscle becomes more positive than about -40 millivolts (the normal resting membrane potential in the smooth muscle fibers of the gut is between -50 and -60 millivolts). The spike potentials last 10 to 40 times as long in gastrointestinal muscle as the action potentials in large nerve fibers, each gastrointestinal spike lasting as long as 10 to 20

neg: Ossicles medium; only about 1/30 of the sound energy moving through the air would be transferred into the liquid. This is observed from the abrupt cessation of sound that occurs when the head is submerged underwater. This is because the relative incompressibility of a liquid presents resistance to the force of the sound waves traveling through the air. The ossicles give the eardrum a mechanical advantage via lever action and a reduction in the area of force distribution; the resulting vibrations would be much weaker if the sound waves were transmitted directly from the outer ear to the oval window. This

neg: Saltatory conduction pair of medial myelinated giant fibers of "Fenneropenaeus chinensis" and "Marsupenaeus japonicus" shrimp, as well as in a median giant fiber of an earthworm. Saltatory conduction has also been found in the small- and medium-sized myelinated fibers of "Penaeus" shrimp. Saltatory conduction Saltatory conduction (from the Latin "saltare", to hop or leap) is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials. The uninsulated nodes of Ranvier are the only places along the axon where ions are exchanged across the axon membrane, regenerating the action

neg: Lorenz gauge condition The Lorenz gauge hence contradicted Maxwell's original derivation of the EM wave equation by introducing a retardation effect to the Coulomb force and bringing it inside the EM wave equation alongside the time varying electric field, which was introduced in Lorenz's paper "On the identity of the vibrations of light with electrical currents". Lorenz's work was the first symmetrizing shortening of Maxwell's equations after Maxwell himself published his 1865 paper. In 1888, retarded potentials came into general use after Heinrich Rudolf Hertz's experiments on electromagnetic waves. In 1895, a further boost to the theory of retarded potentials came after J.

neg: Plasma receiver of charged particles, such as free electrons or ionized gas atoms. Examples of plasma are solar flares, solar wind, neon signs and fluorescent lamps. Plasma interacts with electrical and magnetic fields in ways that can result in vibrations in many frequencies, including the audible range. It appears that Gurnett designed the first plasma receiver, an instrument capable of detecting the vibrations in outer space plasma. These interplanetary plasma vibrations can be transformed into sound waves or air vibrations audible to a human ear. NASA provided recordings of these interplanetary and outer space plasma vibrations to composer Terry Riley and Kronos

neg: Soliton model in neuroscience wave which co-propagates with the electrical action potential. These surface waves are called "action waves". In the El Hady–Machta's model, these co-propagating waves are driven by voltage changes across the membrane caused by the action potential. Soliton model in neuroscience The soliton hypothesis in neuroscience is a model that claims to explain how action potentials are initiated and conducted along axons based on a thermodynamic theory of nerve pulse propagation. It proposes that the signals travel along the cell's membrane in the form of certain kinds of solitary sound (or density) pulses that can be modeled as solitons. The model

neg: Dulong–Petit law the very low (cryogenic) temperature region, where the quantum mechanical nature of energy storage in all solids manifests itself with larger and larger effect, the law fails for all substances. For crystals under such conditions, the Debye model, an extension of the Einstein theory that accounts for statistical distributions in atomic vibration when there are lower amounts of energy to distribute, works well. A system of vibrations in a crystalline solid lattice can be modelled by considering harmonic oscillator potentials along each degree of freedom. Then, the free energy of the system can be written as where the index "α"

neg: End-plate potential less than 1mV in amplitude and not enough to reach threshold. Miniature end plate potentials are the small (~0.4mV) depolarizations of the postsynaptic terminal caused by the release of a single vesicle into the synaptic cleft. Neurotransmitter vesicles containing acetylcholine collide spontaneously with the nerve terminal and release acetylcholine into the neuromuscular junction even without a signal from the axon. These small depolarizations are not enough to reach threshold and so an action potential in the postsynaptic membrane does not occur. During experimentation with MEPPs, it was noticed that often spontaneous action potentials would occur, called end plate spikes in

neg: Molecular neuroscience typically tend to stabilize the cell membrane at the potassium equilibrium potential. As with sodium ions, graded potentials and action potentials are also dependent on potassium channels. While influx of Na ions into a neuron induce cellular depolarization, efflux of influx of K ions out of a neuron causes a cell to repolarize to resting membrane potential. The activation of potassium ion channels themselves are dependent on the depolarization resulting from Na influx during an action potential. As with sodium channels, the potassium channels have their own toxins that block channel protein action. An example of such a toxin is

neg: End-plate potential ion channels in the postsynaptic membrane open causes in influx of sodium ions and a sharp spike in depolarization. This spike causes an action potential to occur and propagate down the postsynaptic membrane leading to muscle contraction. It is important to note that EPPs are not action potentials but that they trigger action potentials. In a normal muscular contraction, approximately 100-200 acetylcholine vesicles are released causing a depolarization that is 100 times greater in magnitude than a MEPP. This causes the membrane potential to depolarize +40mV from -100mV to -60mV where it reaches threshold. Once the membrane potential reaches threshold,

neg: Binaural unmasking authors in the area. The condition names are written NxSy, where x is interaural configuration of the noise and y is the interaural configuration of the signal. Some common values for x and y include: Binaural unmasking has two main explanatory frameworks. These are based on interaural cross-correlation and upon interaural subtraction. The cross-correlation account relies on the existence of a coincidence detection network in the midbrain similar to that proposed by Lloyd A. Jeffress to account for sensitivity to interaural time differences in sound localization. Each coincidence detector receives a stream of action potentials from the two ears via

neg: Kinetic isotope effect determined by the C-H(D) vibrations. For an S1 reaction, since the carbon is converted into an sp hybridized carbenium ion during the transition state for the rate-determining step with an increase in C-H(D) bond order, an inverse kinetic isotope effect would be expected if only the stretching vibrations were important. The observed large normal kinetic isotope effects are found to be caused by significant out-of-plane bending vibrational contributions when going from the reactants to the transition state of carbenium formation. For S2 reactions, bending vibrations still play an important role for the kinetic isotope effect, but stretching vibrational contributions are

neg: Synaptic noise fMRI more useful and trustworthy, research on the noise and ways to dampen it are necessary. Synaptic noise Synaptic noise refers to the constant bombardment of synaptic activity in neurons. This occurs in the background of a cell when potentials are produced without the nerve stimulation of an action potential, and are due to the inherently random nature of synapses. These random potentials have similar time courses as excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs), yet they lead to variable neuronal responses. The variability is due to differences in the discharge times of action potentials. Many types of

neg: P-type calcium channel 1989 because they were discovered within mammalian Purkinje neurons. They were able to use an "in vitro" preparation to examine the ionic currents that account for Purkinje cells' electrophysiological properties. They found that there are calcium dependent action potentials which rise slowly and fall quickly then undergo hyperpolarization. The action potentials were voltage dependent and the afterhyperpolarizing potentials were connected to the spike bursts, located within the dendrites of the Purkinje cells. Without calcium flux in the Purkinje cells, action potentials fire sporadically at a high frequency. P-type calcium channels are voltage dependent calcium channels that are classified under the

neg: Axon a neuron may synapse onto dendrites of the same neuron, when it is known as an autapse. Most axons carry signals in the form of action potentials, which are discrete electrochemical impulses that travel rapidly along an axon, starting at the cell body and terminating at points where the axon makes synaptic contact with target cells. The defining characteristic of an action potential is that it is "all-or-nothing" — every action potential that an axon generates has essentially the same size and shape. This all-or-nothing characteristic allows action potentials to be transmitted from one end of a long axon to

neg: Action potential the muscle to contract. Muscle action potentials are provoked by the arrival of a pre-synaptic neuronal action potential at the neuromuscular junction, which is a common target for neurotoxins. Plant and fungal cells are also electrically excitable. The fundamental difference from animal action potentials is that the depolarization in plant cells is not accomplished by an uptake of positive sodium ions, but by release of negative "chloride" ions. Together with the following release of positive potassium ions, which is common to plant and animal action potentials, the action potential in plants infers, therefore, an osmotic loss of salt (KCl), whereas

neg: Action potential synapses, or to motor cells or glands. In other types of cells, their main function is to activate intracellular processes. In muscle cells, for example, an action potential is the first step in the chain of events leading to contraction. In beta cells of the pancreas, they provoke release of insulin. Action potentials in neurons are also known as "nerve impulses" or "spikes", and the temporal sequence of action potentials generated by a neuron is called its "spike train". A neuron that emits an action potential, or nerve impulse, is often said to "fire". Action potentials are generated by special

neg: Electrophysiology usually detect the activity of at most one neuron. Recording in this way is in general called "single-unit" recording. The action potentials recorded are very much like the action potentials that are recorded intracellularly, but the signals are very much smaller (typically about 1 mV). Most recordings of the activity of single neurons in anesthetized and conscious animals are made in this way. Recordings of single neurons in living animals have provided important insights into how the brain processes information. For example, David Hubel and Torsten Wiesel recorded the activity of single neurons in the primary visual cortex of the

neg: Flat top guitar variations, or stretching. With varying degrees of stretching, the tension varies. This can be thought of as longitudinal vibration. The strings are anchored to the bridge and the pull of the strings is directed to the side of the anchoring point. This creates a torsional force deforming the soundboard. When tension increases, it will create a belly below the bridge (away from the strings) and a dip above the bridge (under the strings). This deformation creates more complex sound waves than the push/pull action. This is different from an archtop instrument, where both longitudinal and lateral vibrations are translated to

neg: Synaptic noise Synaptic noise Synaptic noise refers to the constant bombardment of synaptic activity in neurons. This occurs in the background of a cell when potentials are produced without the nerve stimulation of an action potential, and are due to the inherently random nature of synapses. These random potentials have similar time courses as excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs), yet they lead to variable neuronal responses. The variability is due to differences in the discharge times of action potentials. Many types of noise exist in cells. First, there is intrinsic noise and extrinsic, or synaptic, noise. Within each

neg: Movie projector Optical sound constitutes the recording and reading of amplitude based on the amount of light that is projected through a soundtrack area on a film using an illuminating light or laser and a photocell or photodiode. As the photocell picks up the light in varying intensities, the electricity produced is intensified by an amplifier, which in turn powers a loudspeaker, where the electrical impulses are turned into air vibrations and thus, sound waves. In 16 mm, this optical soundtrack is a single mono track placed on the right side of the projected image, and the sound head is 26 frames

neg: Stimulus modality sends them to receptor cells. The ossicles which are connected to the eardrum pass the vibrations to the fluid-filled cochlea. Once the vibrations reach the cochlea, the stirrup (part of the ossicles) puts pressure on the oval window. This opening allows the vibrations to move through the liquid in the cochlea where the receptive organ is able to sense it. There are many different qualities in sound stimuli including loudness, pitch and timbre. The human ear is able to detect differences in pitch through the movement of auditory hair cells found on the basilar membrane. High frequency sounds will stimulate

neg: Scolopidia the crista acustica, on the other hand, are only found where there is a tympanum, such as on the front legs of insects. Scolopidia A scolopidium (historically scolopophore) is the most fundamental unit of a mechanoreceptor organ in insects. It is a composition of three cells, a scolopale cap cell which caps the scolopale cell, and a bipolar sensory nerve cell. Scolopidia are sensitive to things like sound (vibrations of the air) or substrate vibrations (feeling vibrations on a leaf, for instance) depending on the structure of the overall sense organ in which they reside. These organs ultimately convert mechanical

neg: Birch's law and the velocity of a P wave moving through the material was noted when research was conducted on waves in different materials. In the experiment, a pulse of voltage is applied to a circular plate of polarized barium titanate ceramic (the transducer) which is attached to the end of the material sample. The added voltage creates vibrations in the sample. Those vibrations travel through the sample to a second transducer on the other end. The vibrations are then converted into an electrical wave which is viewed on an oscilloscope to determine the travel time. The velocity is the lender of

neg: Impact (mechanics) projectile is changed into heat and sound energy, as a result of the deformations and vibrations induced in the struck object. However, these deformations and vibrations cannot occur instantaneously. A high-velocity collision (an impact) does not provide sufficient time for these deformations and vibrations to occur. Thus, the struck material behaves as if it were more brittle than it would otherwise be, and the majority of the applied force goes into fracturing the material. Or, another way to look at it is that materials actually are more brittle on short time scales than on long time scales: this is related

neg: Special senses perceive sound by detecting vibrations, changes in the pressure of the surrounding medium through time, through an organ such as the ear. Sound may be heard through solid, liquid, or gaseous matter. It is one of the traditional five senses; partial or total inability to hear is called hearing loss. In humans and other vertebrates, hearing is performed primarily by the auditory system: mechanical waves, known as vibrations are detected by the ear and transduced into nerve impulses that are perceived by the brain (primarily in the temporal lobe). Like touch, audition requires sensitivity to the movement of molecules in

neg: Ventral cochlear nucleus spherical bushy cells likely project to the ipsilateral lateral superior olive. They project neither to the medial superior olives or to the medial nucleus of the trapezoid body. Multipolar cells fall into two distinct groups. Those whose axons project out of the aVCN through the trapezoid body, T stellate cells, have longer dendrites than bushy cells that characteristically lie in line with fascicles of auditory nerve fibers. These principal cells are excitatory. Another name for these cells is 'choppers'. They have an intrinsical rhythm, and will fire action potentials with this rhythm once activated by the right sound. The anteroventral

neg: Action potential is to boost the signal in order to prevent significant signal decay. At the furthest end, the axon loses its insulation and begins to branch into several axon terminals. These presynaptic terminals, or synaptic boutons, are a specialized area within the axon of the presynaptic cell that contains neurotransmitters enclosed in small membrane-bound spheres called synaptic vesicles. Before considering the propagation of action potentials along axons and their termination at the synaptic knobs, it is helpful to consider the methods by which action potentials can be initiated at the axon hillock. The basic requirement is that the membrane voltage at

neg: Energy harvesting that are able to operate in higher temperature gradients, and that can conduct electricity well without also conducting heat (something that was until recently thought impossible ), will result in increased efficiency. Future work in thermoelectrics could be to convert wasted heat, such as in automobile engine combustion, into electricity. This type of harvesting is based on the changing capacitance of vibration-dependent capacitors. Vibrations separate the plates of a charged variable capacitor, and mechanical energy is converted into electrical energy. Electrostatic energy harvesters need a polarization source to work and to convert mechanical energy from vibrations into electricity. The polarization

neg: Myotonia congenita However, many studies have shown that denervation of muscle fibers alter the resting membrane conductance, but whether this affects myotonia in the muscle has been subject to heavy debate, and results from experiments are inconclusive. In skeletal muscle fibers, a large transverse tubule system with a high surface-area to volume ratio exists. The onset of skeletal muscle activity is associated with the initiation and propagation of action potentials again associated with an efflux of K to the extracellular fluid and transverse tubule system. When many action potentials are elicited subsequently more K is expelled from the cell into the transverse

neg: Molecular neuroscience cDNA library which could be used to clone the channel protein. Cloning the channel itself allowed for applications such as identifying the same channels in other animals. Sodium channels are known for working in concert with potassium channels during the development of graded potentials and action potentials. Sodium channels allow an influx of Na ions into a neuron, resulting in a depolarization from the resting membrane potential of a neuron to lead to a graded potential or action potential, depending on the degree of depolarization. Potassium channels come in a variety of forms, are present in most eukaryotic cells, and

neg: Bioacoustics detect and classify the bioacoustic signals. Scientists in the field of bioacoustics are interested in anatomy and neurophysiology of organs involved in sound production and detection, including their shape, muscle action, and activity of neuronal networks involved. Of special interest is coding of signals with action potentials in the latter. But since the methods used for neurophysiological research are still fairly complex and understanding of relevant processes is incomplete, more trivial methods are also used. Especially useful is observation of behavioural responses to acoustic signals. One such response is phonotaxis – directional movement towards the signal source. By observing response

neg: Non-spiking neuron cells, which are a type of non-spiking neurons, undergo a transformation from spiking to non-spiking cells, there have been many studies that try to identify the functional reasons for such a transformation. Starburst amacrine cells use action potentials during retinal development, and once the retina is mature, these cells transform into non-spiking neurons. The change from a cell that can generate action potentials to solely functioning off of a graded potential is drastic, and may provide insight into why the two kinds of neural networks exist. The cells lose sodium channels. The loss of the sodium channels is triggered by