[FoRK] Brain mapping and the connectome

Eugen Leitl eugen at leitl.org
Tue Nov 10 04:50:31 PST 2009


On Sat, Nov 07, 2009 at 10:29:14AM -0600, Jeff Bone wrote:

> (Tangential, but relevant:  even Eugen has probably been relatively  
> surprised by the extent to which non-invasive techniques have  

Eugen is very, very difficult to surprise ;)

> accelerated along the cost / functionality curve in the last decade,  

If you're shooting for whole brain emulation, non-invasive
methods (which we've considered extensively, mostly from the
physical feasibility perspective) fail way before it gets
interesting. Unfortunately.

We don't know how much detail we need, but it could be well around
1-2 nm, with some areas receiving extensive submolecular-resolution 
sampling (it's not enough to get the shape if you don't know salient
properties which don't show up on TEM).

You don't can't pick up a phosphate group in an fMRI scan, or in fact in
any nondestructive scan, sorry. While we've been getting some seriously
high-processivity volume scanners (by iteration of sections), they're
all for extensively fixated and stained (mostly heavy-metal for TEM)
specimens. Nobody has been building a scanner for vitrified native
CNS, at least nobody I'm aware of. 

> cf. comments from early 2000s vs. present, low-function but low-cost  
> consumer products (e.g. EEG game controllers, etc.) --- just the tip  
> of the iceberg, of course.)
> 
>   http://www.foresight.org/nanodot/?p=3475
> 
> 
>   Brain mapping and the connectome
> 
> By J. Storrs Hall, on November 6th, 2009
> I’m at the AAAI Fall Symposium session on Biologically Inspired  
> Cognitive Architectures, and there was a really interesting talk by  
> Walter Schneider of Pitt about progress in mapping the nerve bundles  
> that are the “information superhighways” between the various parts of  

Quaint terminology there, JoSH.

> the brain.  You’ll find his slides from last year’s talk on his home  
> page, and there has apparently been progress amounting to a  
> breakthrough in the interim.
> 
> This and fMRI together are giving us an understanding of what’s going  
> on in the brain that’s advancing faster than anybody (with the  
> possible exception of Ray Kurzweil) thought it would.
> 
> Schneider claims that the techniques now being worked on could be  
> pushed to a resolution of 20 microns, with appropriate resources, by  
> 2014 or thereabouts. That’s essentially good enough to have a complete  
> wiring diagram of the brain.

1 um grid spacing for recording in vivo (with some heavy DSP in situ)
for the entire brain volume over observation window of months to years
might be enough. 

However, you'll notice nobody currently on this list will see that 
technology within what's left of their biological lifetimes.

Unfortunately, the chances of having you cryosuspended in good enough
shape have been sinking for some time now, so no customary cryonics
plug here (unless someone here is interested in spending a decade or
two fixing the situation, which is probably too much to ask for of
anybody).

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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