left-right reversal of CNS: Why?

kenneth paul collins KPCollins at postoffice.worldnet.att.net
Fri Sep 6 04:00:33 EST 1996


>What do you mean by "Topologically distributed"

Somewhat like "topographically-distributed", but also incorporating 
twists and turns and crossings and fiber termination density 
gradients... all of which enter into the formation of 
computationally-relevant maps...

>and what by "Excitation/Inhibition ratio"? 

I'm sorry... that's as simple as I can make it... it's somewhat like the 
algebraic summation that occurs, say, in the dendritic tree of a single 
neuron... only whole "areas"... such as nuclear groups... and their 
projection sites... etc. are taken into consideration...

>What, exactly, do you mean by "TD E/I minimization".

such refers to the convergence upon minimally-activated "states"... of 
all the activations pertaining to all motions that your right arm could 
manifest, for instance, one activation "state" that imparts one 
particular motion to your right arm... with all the other possible 
activation "states" being inhibited, relatively... it's simple... 
without TD E/I minimization, one's behavioral manifestations would be 
something like "catatonic"... everything activated all at once... 
doesn't work... and the less of such all-at-once-stuff, the better...

>How are these things measured and quantified? 

quite arduously... :-)

when I did it, 2 decades ago, I just ransacked the Neuroscience 
stacks... worked mostly with single-electrode experimental results...

>It would seem that the lowest possible E/I(min) could be
>acheived by shutting off excitation completely. For some reason, that
>doesn't sound like its going to explain how the brain works.

well, nervous systems incorporate stochastic input generators (R.F. &c) 
that inject "randomness" into ongoing activation "states"... such 
randomness is then "whittled" down to TD E/I(min) "states"... voila... 
one's right arm does what's useful rather than the myriad other things 
it could do...

>Since you've been posting these terms a lot, could you please give a
>paragraph explaining them, rather than asking everybody to go to a
>separate website?

I put together an intro doc... it's in the NYTimes "Quantum Paradoxes" 
forum... it communicates the bare necessities... ken collins



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