In article <35FBA407.F3A20130 at writeme.com>,
Zoro <Duy at writeme.com> wrote:
> Looking at the auditory pathway, I first proposed that it may be the
> tympanic membrane and/or hair cells which is the limiting factor in the
> ability to descriminate 2 sounds. Unfortunately, texts reveal that hair
> cells are capable of handling up to 1Megahertz of vibration (our results
> show fusion begins around 17 millissec), and is clearly not. Next I began
> to look at the afferent fibers which connect to the hair cells, my group
> advises me that they have an absolute refractory period of 1ms, still not a
> limiting factor. From this I concluded (?) that it must be higher brain
> functions that are the cause of the perception of fusion. My theory is that
> since the noise in the middle is so small, the brain descriminates against
> it, casting it aside as unimportant background noise. Perhaps like the
> blind spot in the eye?
It's interesting the problem here posted, but is clear where the question
arises: Generally the limitations in perceptions could be divided in 3 groups
or levels: a) receptor level, b) transmission level and the processing or
cortical level. I never work in cortical perception or discrimination from
auditory inputs, but I worked in auditory evoked potentials from VII nerve
and in cefalo-oculo-girus reflex in dogs and horses. We found that there is
not difference between normal evoked potentials from both right and left ear,
but in dogs we found a significant difference between latency in response to
the head movements to a sound source, being the right response shorter than
left. The difference in your case could be at the third level, in cortical
discrimination. And experiment with evoked potential could be interesting:
Normally the auditory pathway have 3 high point in EEG one at coclear and
vestibular nucleus (ipsilateral) 2 at thalamic nucleus (contralateralis) and
3 at temporal corticle (contralateral) the absence of one of them could mark
the point in the pathway where the stimulus lose its efficacy. Luck...
Carlos Blanco.
Neuroanatomy research team. FCV:UBA.
>
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
http://www.dejanews.com/rg_mkgrp.xp Create Your Own Free Member Forum
