Hearing And Brain

[orbsycli]

Ok so is the left ear gathering data for the right side of the brain,
and the right ear is doing the same for the left?

Or is hearing in general operated by a certain part of the brain?

What part?

[InfiniteNow]

Originally Posted by orbsycli

Ok so is the left ear gathering data for the right side of the brain,
and the right ear is doing the same for the left?

Or is hearing in general operated by a certain part of the brain?

What part?

Yes, they are gathering information for the opposite side, but also their own.


There is no one part of the brain involved in hearing. There is an initial interpretation involved which dicates what parts of the brain are activated, but this is done at the synaptic level, and usually before any signal has reached the brain.

Think, for example, of a time when you heard the wheels of a car which is heading toward you begin screaching. What happens? Your heartrate picks up, your pupils dialate... all of your resources became attuned to that stimulus. You didn't have to sit there and think:

Okay, that was a sound.
Hmmm... sounds like it's coming from over there.
I've heard something like this before, I think.
Yes, yes I have. Those are rubber tires on a car having a high friction response to the pavement.
Oh... that could be bad.
That might mean I'm about to get run ov..... CRASH!!!!

"We've lost him doctor."


It just happens, and quickly (for which the example above clearly demonstrates the reason it evolved as such).

It's a whole complex symphony between the actual area of the body doing the receiving of the input, the nerve cells sending that signal, and a whole number of intermediate signal/response locations which have evolved to speed reaction time before the signal reaches any particular part of the brain. In this case, the auditory nerve.

Another point is that the part of the brain which knows that my fingers are making the sound on this keyboard right now as I type is different than the parts that are activated when I have a conversation with the attractive female sitting beside me.

But, it is on both sides, and a whole bunch of different parts of the brain are involved as well. However, if I had to answer "What ONE part of the brain is primarily responsible for auditory stimuli?" ...I'd say, sorry, I don't know how to limit it to just one part.


This link might shed some further light on to the subject:

http://en.wikipedia.org/wiki/Psychoacoustics
http://www.cs.cf.ac.uk/Dave/Multimedia/node270.html

[orbsycli]

beautiful, thank you.

[Racoon]

It's the hair cells, and their bending, that are key to hearing.

and resting on the basilar membrane is a specialized organ called the ' Organ of Corti "
Eventually pressure waves enter through the Cochlea and push against ' the round window ' . The hair cell bending causes action potentials in neurons of the Auditory Nerve.

[InfiniteNow]

Originally Posted by Racoon

It's the hair cells, and their bending, that are key to hearing.

and resting on the basilar membrane is a specialized organ called the ' Organ of Corti "
Eventually pressure waves enter through the Cochlea and push against ' the round window ' . The hair cell bending causes action potentials in neurons of the Auditory Nerve.

That's right. They're called "Cilia." Calling them hairs may imply a size they don't have, but they are tiny hair-like protrusions in the OOC.

Interesting piece of trivia... part of the reason we feel so dizzy when drunk (think "bed spins") is because the alcohol has, to some extent, entered the fluid in our ears in which these cilia reside, and the alcohol changes the fluid's natural viscosity. This means that the brain's interpretation of the normal sloshing from side to side goes all haywire and the information received from our ears conflicts with the information received from all other parts of our body... hence, we feel sick.

[Turtle]

___Bed spins! Now there's an ear phenom I haven't experienced in decades!

___The first thought I have on hearing is my loss of it. Last time I went to have my hearing tested, they found I have lost about 40% of my hearing in the 2,000-4,000 Hz range; this is the range most English conconants fall in, & as a consequence I have a lot of difficulty inderstanding words.(They told me no hearing aids correct this) I also damaged the little auto-valve at the throat end of the eustacheon tube, so I often 'jack' my jaw to get it to open & equalize the pressure; a little gift of SCUBA diving during allergy season.
___Besides the range indicated above, I have lower losses in other frequencies. I likely bear the responsibility for the loss due to years of unprotected exposure to loud rock & roll, gunfire, & industrial equipment in cabinet shops. Wear your hearing protection!
___The last little hearing gem for me is tentenitus(sp), which the audiologist says they don't know the cause of. I constantly hear three distinct & very high 'whistling' tones in my ears (head?).
___My brain thinks my hearing sucks & blows!

[InfiniteNow]

Originally Posted by Turtle

___Bed spins! Now there's an ear phenom I haven't experienced in decades!

___The first thought I have on hearing is my loss of it. Last time I went to have my hearing tested, they found I have lost about 40% of my hearing in the 2,000-4,000 Hz range; this is the range most English conconants fall in, & as a consequence I have a lot of difficulty inderstanding words.(They told me no hearing aids correct this) I also damaged the little auto-valve at the throat end of the eustacheon tube, so I often 'jack' my jaw to get it to open & equalize the pressure; a little gift of SCUBA diving during allergy season.
___Besides the range indicated above, I have lower losses in other frequencies. I likely bear the responsibility for the loss due to years of unprotected exposure to loud rock & roll, gunfire, & industrial equipment in cabinet shops. Wear your hearing protection!

Your cilia have been accosted by such repetition of such a powerful signal... the sound comes in, the wave motion of the fluid pushes/bends the cilia which generates a neural signal sent for interpretation... that the cilia literally broke. They snapped like a twig at that particular range and they no longer send/create a neural signal... and they don't grow back.

<pours a 40oz bottle of Mickey's malt liquor toward the ground>
"This one is for all our fallen cilia."

<...and everyone around me said...> Huh? What'd you say?

[Racoon]

well said InfiniteNow!

The part of our ears that deal with "balance" are the 'Vestibular Apparatus' and the 'Semi-circular canals'.!

The Vestibular apparatus is a closed system of fluid filled canals and sacs. The Semi-circular canals are positioned at right angles to one another to represent the three planes of space. Inside them sensory receptors monitor dynamic equilibrium- meaning rotating head movements.

Otolith organs (in Utricles and saccules) contain sensory hair cells embedded in a jelly like membrane. Movements of the membrane and Otoliths signal changes in the heads orientation relative to gravity! As well as straight-line acceleration and deceleration..

Racoon has a "Human Biology" Textbook from College sitting next to him