IUBio Biosequences .. Software .. Molbio soft .. Network News .. FTP

Sundowning: severe dementia and bringing on the night (corticosterone increases aggression in the rat)

BilZ0r BilZ0r at TAKETHISOUThotmail.com
Thu Apr 3 01:35:54 EST 2003


> There are neurons that manifest impulse activity. With respect to
> such, if an impulse generates increased activation, it is
> "excitatory". If it generates decreased activation, it's
> "inhobitory".
> 
> Within the nervous system, neurons are organized in a rigorously
> topologically-distributed fashion. A tract, for instance, might
> 'twist' around as it travls into the nervous system so that the
> neighborhood relationships among the neurons comprising the tract at
> the body-environment interface [say the skin] get turned upside-down
> en masse. This sort of thing happens commonly within the neural
> Topology, and is what enables various 'areas' of the nervous system
> to interact gracefully [with optimal efficiency] - which is important
> because 'graceful' neural activation correlates with minimal response
> latencies, which correlates to enhanced survival propensity.

Okay, outside the CNS, nerves don't do that at all. Any of the 
parasympathetic nerves? In fact the whole autonomic system isn't set up 
how you suggest, that could be a whole lot more efficient as far as speed 
is concerned. 


> Such Topological structure is, itself, an instance of TD
> E/I-minimization because, if it didn't happen, there'd be the need
> for mor-complex interconnectednessm say, via a set of interneurons
> that 'bridge' the non-topologically-aligned structure to create a
> version of the 'graceful' Topology, but in which all pathways have
> increased length.

 
> Increased path length = lengthened response latencies and reaction
> 'times', so this 'bridged'-by-interneurons Topology can't compete
> with the 'gracefully'-aligned neural Topology, because the 'graceful'
> neural Topology always works faster - which is why the 'graceful'
> neural Topology became ubiquitous during the course of evolutionary
> dynamics.

In the CNS, how about the path the optic tract takes past the LGN? The 
optic radiation isn't as straight as it should be. And the Corpus 
callosum, why is it so small, it should extend all the way to the back of 
the calcirine sulcus inorder to minamize the distance that the optic 
cross over fibres take. Oh, and the path the IV and the VIII cranial 
nerves?

 
> All of the above applies in the abstract with respect to excitation
> and inhibition -minimization of the ratio of excitation to inhibition
> reduces response latencies and reaction 'times' allowing a system
> which performs such minimization to out-compete any system that does
> not.

If its all about responce latencies, why do we have so many GPCRs? LGICs 
are far faster. phase out GABAb, all GABAa eh?

 
> Put all of this together and you get Topologically-Distributed
> minimization of the ratio of Excitation to Inhibition - TD E/I(min).

If you minimised the RATIO of Excitititory recpetors over inhibitory 
receptors you'd have a brain full of inhibitory receptors... I don't see 
how that makes anything faster.
It might minimise the ENERGY used in tranmission, but it would result in 
a scrambled signal. and if the ratio was important you could then you 
could just add say 50% more receptors of each kind ( Excit. vs Inhib.) of 
receptors and you wouldn't alter the ratio, so again, I don't see why 
this ratio is so important.

Now the idea of putting this that work together close together (esp. in 
the cortex) is accetped, somatopy in the Frontal and prefrontal cortices, 
retinotoy in V1. But its far from the rule, How about all of the thalamic 
nuclei? and the SMA?

And again I ask, How does minimizing a ration lead of cognition?

 
> There is. The order differential inherent in WDB2T is. itself, an
> energy-gradient.

Okay, you lost me there. As far as I was awear the 2nd law of 
thermodynamics was simply a statment that "The entroy of an isolated 
sysmtem always increases" One can use that statement to construct 
mathamatical equations, but there is no gradient. Entropoy can exsist 
quite happily without an gradients of any kind.

 
> All that stuff that flows from high concentration through a
> semi-permeable barrier to low concentration does is follow the WDB2T
> energy-gradient, until 'equilibrium' is 'reached' ['equilibrium' is
> never actually attained because WDB2T is ubiquitous, everywhere
> within physical reality, 'going' in the one direction - evaporation,
> heat radiation, the heat radiation that underpins condensation, etc.
> WDB2T is always in-there, everywhere within physical reality..

See, this is where you go wrong. the 2nd law of thermodynamics is an 
emperical law, its not based on anything but experiments, its like a 
framework in an argument, all of those examples can be explained through 
it, but it is not needed for them to happen. You can use the 2nd law to 
explain a lot of non physical phenomina, like economics and law.

> 
>|The brain could theoretically work with
>| almost no entropy change.
> 
> Not True.

Yes it is true, it is absolutly and unevquivocable true. Imagine if VSSC 
and VSCC were sensitive to a change from 0mv to 0.1mv, we can construct 
diodes that are sensitive to millions of times less change, so why not a 
channel? Then we can have the brain resting at ionic equilibrium, and 
instead of a depolaristion of 25mv, one of 0.1mv would be all that was 
neccassary. Then a AP could be a transient change of 0.5mv. After that 
the brain would work exactly the same, except Na/K ATPase activity would 
have to be turned down a whole lot. There we've reduced the entropy 
change massivly.

 
>| Life dosn't move toward anything, and it
>| certainly dosn't move toward energy abundance, if anything life
> lowers
>| the amount of free energy in a system.
> 
> That Life 'climbs' the WDB2T energy-gradient doesn't mean that Life
> doesn't 'consume' useable energy. Life does, which is why Life =must=
> 'move toward' increasing energy abundance [relative to energy within
> itself] - if it doesn't, Life ceases via energy-depletion.
> 
> If you doubt, stop eating [don't really :-]
If we looked at me during my post adolencent life. I have lost total 
energy if anything. I consume it, use it, and then loss it, there is no 
accumlation leading to abundance. And if we're going to go back to 
entropy, which I wish we had never touched on in the first place, my 
entropy over my life time decreases

 

>| and stop citing your own unpublished works, its unproffesional.
> 
> I'm an Amateur, anyway. My work is 'correct'. It's not published.
> What would you have me do?

Cite material published in peer review journals. Theres millions of 
neural network experiments published that you could use to support your 
ideas (or hopefully refine them)
 
> ken collins 




More information about the Neur-sci mailing list

Send comments to us at biosci-help [At] net.bio.net