The Cochlea is a Tube, which is formed like a snyaol, it consists of three chambers (vestibular canal, Middle Canal & Tympanic canal
The Main organ that generates sound is the organ of Corti, which lies on the Membrane between the Canals, it has a lot of Haircells on it. Folie8 Pretty difficult tastk to go from changes in Airpressure to electric Signals.
The Haircells are located in different Rows, We don't fully know what the outer haircells do (we have 3 Rows of them) and one row of inner Haircells, which are very important for our hearing.
Impedance matching, grat amplification, most Amplification is beacause the tympanic membrane is 17 times larger than the stapes.
The waves generated by the Airpressure move the basilarmembrane. The haircells are attached to the basilar membrane. antd the hair are embedded in the tectorial membrane. if there is a change in pressurethe Membranes move relative to one another, since the Haircells connect the Membranes, the Hairs will move relative to their cell bodies
Perilymph in the outer two Canals, it's high in Na and low in K Endolymph in the middle canal, high K and low Na concentration
Organ of Corti
outer Haircells detect the Presence of soud, they are able to change the flexibility of their cilia, if there is an intense sound the get hard and restrict a too strong movement. the inner haircells exist for fine auditory discrimination.
Transduction at hair cells
different Part of Membrane vibrate at different frequencies. We have a tonotopic organsiation n the basilar mambrane, this organisation is represented like this all the was to the cortex.
Bot how do we have such a huge range fom 15-15000 Hz? it cant be just beacuse of the place principle
Volley principle & Loudness
The A1 is also organized tonotopic, A1 is very strong in sound discrimination, but A1 does not give any "meaning" to the sounds, it just discrimantes them. As soon as you are hearing words wernickes Area gets active and gives meaning to the soundpatterns.
Perception of pitch
Physical property of sound and how we percieve it (in vision different frequencies Relationship between frequency and pitch is not 1:1 there is also a difference between intensity and loudness.... loudness is something that changes with perception, ifyou keep intensity and change frequency, sounds seem louder etc. Same with Pitch
timbre Differences between trumpets and saxophones, main frequency is same, but harmonics are different, it gives a different quality to the Sound.
How do we percieve sounds in space? Doppler shift, if you have a source thats emitting sounds it influences the frequency that the sound has, brain has learned to interpret this sounds.
Cocktail Party Effect
In an environement with many sources it is easier to process auditory streams if they are seperated spatialy. Better at following discussions in reality than with headphones.
Two main cues
ITD interaural time difference and IID interaural intensity difference (sound shadow) Time Difference is 600 microseconds, brainstem is extremely precise at localizing it.