decussation of pyramids in brain stem

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Dear Anybody,

Does any member know the reason why decussation takes place in the brain stem, i.e.: why the left side of the brain affects the right side of the body and visa versa? This question was posed to me the other day by a Physiotherapist, and I haven't been able to sleep since!

Please Help

insomniac

-- Matthew Dilosa (newlife@netspace.net.au), November 29, 2001

Answers

Matthew - go to sleep!! My theory is that the physiotherapist is doing a PhD on the subject and is getting you to do all the hard work.

One of my textbooks notes that "the adaptive value, if any, of this phenomenon is nuknown".

A quick search through the net sheds a little more light on the topic if you consider the eyes: "notice the decussation at the bottom of the brain. All mammals have a decussationof some kind, but this can vary quite a bit from species to species depending largely on the location of the eyes.

To understand why, realise that the goal of the decussation is to produce unified views of each hemi-field of space in the opposite hemisphere.

If you insist on making your life more complicated try www.neuropat.dote.hu - this site has EVERYTHING you ever wanted to know about the nervous system.

Diana

-- Diana Glazer (dglazer@zip.com.au), December 03, 2001.


Hi Matt

I cannot resist muddying the pool and deprifying you of more sleep - The motor decussation is absolute - L controls R and vice versa - The eye decussation is partial - central vision versus peripheral - Thus spatial relationships are available for cortical integration- Did it start when we were worms crawling through a tunnel? But why is calculation (male)on one side and artistic integration (female) on the other - Tortora on the primitive disc could be a starting point -

With tongue in cheek and kind regards - Joel Morrell

-- Joel Morrell (arn@tsn.cc), December 06, 2001.


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