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[OM] Re: Switching eyes...

Subject: [OM] Re: Switching eyes...
From: Fernando Gonzalez Gentile <fgnzalez@xxxxxxxxxxxxx>
Date: Tue, 28 Mar 2006 23:31:18 -0300
Perhaps not the best idea to get into these details here, but just can't
help it since I thought over on this topic this afternoon.
My point is that having a dominant eye needs a different neurological
explanation from being right/left/ambidextrous handed.
If a person is right-eyed, the right 50% of the retina (temporal half) of
his right eye and the right 50% of the retina of his left eye (nasal half)
will input the right occipital lobe of his brain.
But when a person is right-handed, most neurons of '4' left motor cortex
area will input his right arm muscles, and sensitive nerves from right arm
will input his left parietal cortex. Dr.Penfield was the first to find out
how those areas are drawn onto the cortex surface.
At the moment, I don't find why a right-eyed person should be either
right-handed or left-handed; this, even taking into account that the
external (and almost sure about, the internal - but don't feel like getting
into autonomous inervation now) muscles that move the eye-globe receive
their input from three cranial nerves which first neuron are located in the
lower brain and, AFAIK, don't cross to the opposite part - they're
ipsilateral.
Eye dominance should be, in my very humble opinion, easier to switch since
it only involves sensorial information from the 2nd cranial pair, and very
simple motor coordination from the 3rd, fourth and sixth cranial pairs.
Sensorial input to each occipital lobe should be very similar, I'd say
_must_ be very similar.
Perhaps we're accustomed to name an eye as 'dominant' just because it's
easier to keep it open while looking at something, because of better control
of its eye-lid, whose muscles receive input from neurons of '4' left motor
cortex area, just as the right hand does.
Complex coordinated movements starting from visual input and generating
(left or right-preferred) motor response, may also justify the nomenclature
I'm discussing here. Furthermore, these complex coordinated movements may
start from a right-handed-easyness and then monitored by one preferred
eye...
Hope this makes sense to anyone, I didn't use spell checker and won't read
it twice. Opinions welcomed.

Fernando.

on 28/03/2006 14:00, Tim Hughes at timhughes@xxxxxxxx, wrote:

> I don't always use the same eye but often use left, even though I am nominally
> RHanded.
> If I shoot a rifle it gets interesting as I put the rifle butt to the right
> shoulder and usually
> use left eye. I was somewhat ambidexterous as a child. I used to write on the
> right page with my
> right hand and on the left page with my left hand. Whatever you do seems to
> get to feel natural
> eventually, I think.
> Tim Hughes
> 
> --- Michael Collins <l43g20th@xxxxxxxxxxxx> wrote:
> 
>> I've been right-handed and right-eyed all my life, as far as a camera is
>> concerned, but all of a sudden need to become right-handed/left-eyed.


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