[Neuroscience] Re: Distant connections between neurons

ganges ganges.g at gmail.com
Fri Mar 31 20:56:18 EST 2006


Hi, feedbackdroids

Satisfied with your answer. I would like to know more on this topic. could
you plese suggest some articles?

Recently I was working on computational modeling of Motor system. In which I
have obrseved , if i have long range connections along with local
connectoins, the synchronization time was decreasing drastically.

i thought may be long range connections are ncessary for bringing different
cortical reaagion to get synch for some extent.

Where as the Local connections sets the phases.

Thanks for the comment.

Gangadhar.G

On 31 Mar 2006 08:52:35 -0800, feedbackdroids at yahoo.com <
feedbackdroids at yahoo.com> wrote:
>
>
> ganges wrote:
> > Can neuroscince tell the fucntional significance of long range
> connections.
> > What is the signifincance of local densed connections, Long range
> > connections etc?
> > Any idea?
> >
> > Having long range connections has any link to small world
> networks(Dynamical
> > sytems terminology)
> >
> > waiting for some one's reply
> > Gangadhar.G
> >
>
>
> In fact, this is a good observation, and probably true. There are many
> "levels" of processing in the nervous system, but even so, behavioral
> responsivity times are quite fast. EG, by rough estimates from people
> like vanEssen, there are maybe 10-13 levels just in the visual system
> alone. And this is just on the sensory side, and not counting any
> central processing beyond vision or the several levels of processing on
> the motor response side. If the system of the brain were simply one
> level after another after another of more or less "linear" processing,
> then it would take a long time for an animal to respond to external
> stimuli.
>
> The way this problem is apparently shortcut is by the presence of many
> reciprocal feedback pathways that exist between cortical regions in the
> white matter. Edelman in his several books has pictures showing 50+
> cortical areas in the cat cortex interconnected by 1000+ feedback
> pathways. This is a very high degree of connectivity. These pathways
> turn the system from a sort of "linear" arrangement into something more
> like a small-world network that you mentioned, and you know from the
> dynamics of small-world networks that adding just a few global
> cross-connections greatly reduces the time it takes signals to traverse
> the network. So, this is how you can get fast responsivity in a complex
> system with many processing levels.
>
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--
G.Gangadhar,
MS - Controls,
Artificial Neural Networks Lab (ESB-204B)
Electrical Department,
IITM, Chennai,
INDIA.


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