Audition/Taste/Smell (CH. 9) part 1- audition

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audition
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Terms in this set (23)
audition
refers to our sense of hearing and depends upon our ability to detect sound waves
sound waves
periodic compressions of air, water, or other media
what are some properties of sound waves?
-sound is a pressure wave generated by certain types of mechanical force
-involves longitudinal oscillations (increases and decreases) in air pressure
-sound can be described in terms of its wave-like properties, although it is a longitudinal wave
how can sound be characterized?
by amplitude and frequency
how is frequency measured?
it is measured in cycles / second (the number of wavelengths passing over a point in space per unit time)
higher frequency= more waves per second - usually perceived as a higher pitch
pitch
the term used to define the perception of a sound (usually in terms of frequencies)
loudness
defined by the amplitude or height of the sound wave
fourier analysis
a set of mathematical formulas for deconstructing complex wave forms (sound) into seperable sine waves
-therefore, sound, and auditory perception- can be understood in terms of their component frequencies and amplitudes
outer ear
pinnae- structure of flesh and cartilage attached to each side of the head
responsible for altering the reflection of sound waves into the middle ear from outer ear & helping to locate the source of a sound
middle ear
tympanic membrane, ossicles- contains the eardrum which vibrates at the same rate when struck by sound waves
connects three tiny bones, called ossicles (malleus, incus, and stapes) that transmit larger waves from the tympanic membrane to the smaller oval window
oval windowmembrane on cochlea -transmits waves through the viscous fluid of the inner earinner earcontains a snail shaped structure called the chocleahair cells (HCs)auditory receptors residing in the cochlea, between the basilar and tectorial membranes -when displaced by vibrations in the fluid of the cochlea, these cells excite the cells of the auditory nerve -depolarize via entry of K+ and Ca2+organ of corticollective name of all structures in scale media (hair cells, etc.) that convert sounds into neural activitysterocilliahair-like objects on hair cells, that are deflected by pressure (i.e. sound) and depolarize the membrane -non-selective K+ and Ca2+ channels are opened in hair cells when they movehow is sound coded into electrical impulses?1. temporal coding 2. place codingtemporal codingencoding of sound as a function of number of action potentials per second at same frequency of the actual sound -AP that is generated will have the exact same pattern frequency as the soundwave (but the MAX AP frequency is only 1 ms)place codingeach area along the basilar membrane has hair cells sensitive to only one specific frequency of sound wave -this is the classing "labeled-line coding" strategyamusiatone deafness-the impaired detection of frequency changesauditory pathwaysafferents from the cochlea travel via the vestibulocchlear nerve (cranial nerve VIII), ipsilaterally, to the cochlear nucleus in the brain stem -then axons project both ipsi and contralaterally to superior olivary nucleus -from here, inferior colliculus--> medial geniculate nucleus (MGN) ---> cortical regions important for auditory processingwhy do the superior olivary nucles and inferior colliculus play important roles in sound localization?temporal segregation of bilateral inputsprimary auditory cortex (A1)located in the superior temporal corext, it is the destination for most info. from the auditory system *each hemisphere receives most of its info. from the contralateral side -important for processing complex sounds (mostly in our daily experience)what are the 2 main streams of auditory processing in the cortex?1. dorsal stream- focuses on localization 2. ventral stream- analyzes components of sound