[MURG] Non-invasive 3-D Scanning

[Yan King Yin]

From: "Joseph J. Strout" <joe at strout.net>

>>I know, high-resolution non-invasive scanning is
>>unfeasible because of the short wave-length
>>requirement that will evaoporate the brain. But
>>there may still be hope. Suppose we just want to
>>scan the 3-D connectivity. This requires a resolution
>>of about 0.3um.
>
>How do you figure that?  The connections (axons, dendrites (including 
>spines), and synapses) are pretty much the finest level of detail we 
>need; cell bodies are much bigger.  It's from the assumption that we 
>need to capture these, that the estimate of 10 nm resolution is made. 
>(If you look at an electron micrograph at a 10 nm resolution, you can 
>clearly see the structures.  At 0.3 um, or even 0.1 um (100 nm), you 
>won't be able to adequately resolve important things like synapses 
>and spine necks.

I said that because the smallest axons/dendrites
in humans are > ~0.1um. I was thinking to scan the
*connectivity* only and then use microprobes to
extract synaptic strength information ;)  In other
words the 3-D scanner determines which neurons
are connected to which, and also gives some
branch morphology info. If that's the requirement
maybe it'll be feasible.

YKY


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