Introduction
The human auditory system is incredibly accurate in identifying signal content, location, and meaning through discrete neurological processes. The accuracy of these processes begins at the external, anatomical portions of the auditory pathway: the pinna and ear canal. The pinna serves to collect sound from the environment and generate direction-dependent cues through spectral transformations (Hofman, et al, 1998; Raykar, et al, 2005). Sounds that are funneled into the ear canal contain range of frequencies that are amplified and attenuated. This interaction of complex sound waves, based on the unique shape of an individual’s pinna, results in a transfer function used for localization in the vertical plane (Hofman, et al, 1998, p. 417). There is evidence that the spectral notches and peaks formed when sound interacts with the pinna are a key component to localization of sound in the vertical plane (Raykar, et al, 2005, p. 364). The spectral changes caused by reflections of sound waves on the unique curves of the pinna are referred to as “spectral patterning”. This occurs primarily in frequencies above 6 kHz, as the wavelength of the sound is short enough for it to interact with the pinna. This indicates that sound localization is influenced most by high-frequencies (Moore, 2007, p. 186).
Each individual ear is unique and provides frequency information not offered by any other facet of the auditory pathway. The distinctive curvature and overall shape of the pinna aids in shaping complex signals to determine spatial information by integrating the frequency transforms for both ears. Therefore, it is important to be capable of receiving sound binaurally to accurately locate the signal in space and to reduce ambiguity withi...
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Works Cited
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Hearing allows us to take in noises from the surrounding environment and gives us a sense of where things are in relation to us. All those little folds on the outside of the ear, called the tonotopic organization, make it so sound waves in the air are directed to the ear canal, where they can be further processed. Once in the ear, the sound waves vibrate the ear drum, which tell the ear exactly what frequency it is sensing. The vibration of the ear drum is not quite enough to send a signal to the brain, so it needs to be amplified, which is where the three tiny bones in the ear come into play. The malleus or hammer, incus or anvil, and stapes or stirrup amplify this sound and send it to the cochlea. The cochlea conducts the sound signal through a fluid with a higher inertia than air, so this is why the signal from the ear drum needs to be amplified. It is much harder to move the fluid than it is to move the air. The cochlea basically takes these physical vibrations and turns them into electrical impulses that can be sent to the brain. This is...
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Cochlear Implants only restore very limited audibility. When described by formerly hearing Deaf people they compare it to hearing underwater, “fuzzy and timbre” yet still able to discern some
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Audition is a complex process that involves multiple areas of the brain. To be able to hear sound is just the beginning. Understanding speech and appreciating music requires an intensive and complex network of processes still yet to be understood. Many auditory processing deficits have been discovered with varying degrees of specificity and severities. A whole area of research has been dedicated to finding solutions to these auditory deficits that many ...
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From this point, vibration of the connective membrane (oval window) transforms mechanical motion into a pressure wave in fluid. This pressure wave enters and hence passes vibrations into the fluid filled structure called the cochlea. The cochlea contains two membranes and between these two membranes, are specialized neurons or receptors called hair cells. Once vibrations enter the cochlea, they cause the lower membrane (basilar membrane) to move in respect to the upper membrane (i.e. the tectorial membrane in which the hair cells are embedded). This movement bends the hair cells to cause receptor potentials in these cells which in turn cause the release of transmitter onto the neurons of the auditory nerve.
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It is a well established fact, that during the fetal period, the brain undergoes extensive developmental changes, with new synapses being formed continuously in response to external cues being delivered to the fetus. This development of neuronal connectivity enables the fetus to recognize and analyze complex information. This is especially true in the development of the auditory nervous system. A strong model of the auditory development in response ...
The ear is an organ of the body that is used for hearing and balance. It is connected to the brain by the auditory nerve and is composed of three divisions, the external ear, the middle ear, and the inner ear. The greater part of which is enclosed within the temporal bone.