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New Imaging Method Reveals Brain Connections
An anonymous reader writes "Researchers at the Stanford University School of Medicine, applying a state-of-the-art imaging system to brain-tissue samples from mice, have been able to quickly and accurately locate and count the myriad connections between nerve cells in unprecedented detail, as well as to capture and catalog those connections' surprising variety. A typical healthy human brain contains about 200 billion nerve cells, or neurons, linked to one another via hundreds of trillions of tiny contacts called synapses. It is at these synapses that an electrical impulse traveling along one neuron is relayed to another, either enhancing or inhibiting the likelihood that the second nerve will fire an impulse of its own. One neuron may make as many as tens of thousands of synaptic contacts with other neurons, said Stephen Smith, PhD, professor of molecular and cellular physiology and senior author of a paper describing the study, to be published Nov. 18 in Neuron."
I for one welcome our new brain scanning overlords!
So they have this wonderful new imaging method that can show something unseen until now... and they have no pictures with the article.
Seriously?!
Researchers at Stanford imaged my brain so quickly that they got me to make this first post remotely.
America, Home of the Brave.
Another amazing technological step in the biology field. Its only a matter of time before we can the other 90% of our brain. We could even use, dare I say... Brain Control?! (Which is different from mind control)
...on my cryonically preserved brain?
A slab of tissue — in this case, from a mouse's cerebral cortex — was carefully sliced into sections only 70 nanometers thick. (That's the distance spanned by 700 hydrogen atoms theoretically lined up side by side.) These ultrathin sections were stained with antibodies designed to match 17 different synapse-associated proteins, and they were further modified by conjugation to molecules that respond to light by glowing in different colors.
In case you were wondering, you have to be dead to be scanned with this technique, and it doesn't look like they will be able to press a button and scan a whole brain.
http://michaelsmith.id.au
Hopefully this will lead to further breakthroughs in biometric prosthesis. If they can map out where the nerves are and what their functions are more accurately, we may soon be able to interface with them more directly. Imagine a prosthetic arm that actually has feelings versus our current ones that only have motion. This could a a very good thing... or scary for those afraid of cybernetics.
Are these the human-brained mice of which I've heard so much of late?
This is immunohistochemistry, just scaled up to many different antibodies for the same sample and realigned in space.
Also, the connectivity is lost. You can't tell which neurons are connected to which other neurons. The overall circuitry, essential for the functioning of neural networks, is invisible. All you can see is points of contact between neurons.
Perhaps combining this technique with super high resolution diffusion tensor imaging would be a way forward. Although, as far as I know, DTI is nowhere near neuron or axon resolution as of yet.
So they can't take a picture of the images that are produced.
Also, I'd be interested to see how (or if) they managed to completely wash off antibodies between scans without damaging the tissue or disrupting synaptic structure. Many synaptic proteins recognize and bind each other in the same way that antibodies bind their antigens, so it stands to reason that disrupting antibody binding would also disrupt the binding of these proteins.
"Researchers ... have been able to quickly and accurately locate and count the myriad connections between nerve cells in unprecedented detail, ..."
Zuckerberg is working on an API for this right now.
What one fool can do, another can. (Ancient Simian Proverb)
From the CNET article:
They found that the brain's complexity is beyond anything they'd imagined, almost to the point of being beyond belief, says Stephen Smith, a professor of molecular and cellular physiology and senior author of the paper describing the study: "One synapse, by itself, is more like a microprocessor--with both memory-storage and information-processing elements--than a mere on/off switch. In fact, one synapse may contain on the order of 1,000 molecular-scale switches. A single human brain has more switches than all the computers and routers and Internet connections on Earth.
This is why I am extremely skeptical of claims that we will be able to effectively model the brain, or recreate it artificially, any time soon.
RUGBYRUGBYRUGBY
I was just about to come here and mention DTI, but you beat me to it.
I'm not sure if they're down to neuron/axon resolution yet, but I do know they're pretty close. Dr. Walter Schneider at the University of Pittsburgh has created a movie image of the various connections in his brain.
http://www.lrdc.pitt.edu/schneider/
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I need an upgrade desperately.
Please do not read this sig. Thank you.
Is this going to replace the back scatter scans as the new TSA scan of choice?
but.. pics or it didn't happen. Thx.
I wonder if they imagined we would be impressed by this "finding".
Pics or it didn't happen
Main difference between the BSD license and the GPL license: one is from California and the other is from Massachusetts
I'm not looking forward to when we can synthetically reproduce and upgrade our brains with new computing-like technologies. I don't want to have to pay millions of dollars for getting songs stuck in my head.
"Researchers at the Stanford University School of Medicine, applying a advanced imaging arrangement to brain-tissue samples from mice, accept been able to bound and accurately locate and calculation the countless access amid assumption beef in aberrant detail, as able-bodied as to abduction and archive those connections' hasty variety. A archetypal advantageous animal academician contains about 200 billion assumption cells, or neurons, affiliated to one addition via hundreds of trillions of tiny contacts alleged synapses. It is at these synapses that an electrical actuation traveling forth one neuron is relayed to another, either acceptable or inhibiting the likelihood that the additional assumption will blaze an actuation of its own. One neuron may accomplish as abounding as tens of bags of synaptic contacts with added neurons, said Stephen Smith, PhD, assistant of atomic and cellular analysis and chief columnist of a cardboard anecdotic the study, to be appear Nov. 18 in Neuron." web designing company in chandigarh thanks....
http://en.wikipedia.org/wiki/Connectome
which is a map of the neural connections in the brain.
I highly recommend watching this vid, demonstrating the "New Imaging" methods, its also quite humorous.
http://www.ted.com/talks/lang/eng/sebastian_seung.html
The lunatic is in my head
The summary only mentions electrical pulses, it should have mentioned that the local chemical environment is part of the information exchange.
I do this exact research (diffusion weighted imaging of human brains). We are no where near neuronal/axonal resolution with diffusion weighted scanning (DTI is a special case of diffusion weighted scanning - there are better methods than DTI for analyzing images: e.g., http://brainybehavior.com/neuroimaging/2010/08/hardi_vs_dti/).
With live humans we only resolve down to about 2mm^3. There are many neurons and axons in that space. At best for the whole brain we create only a few fibers for that 2x2x2 mm area when in reality there are tens of thousands to millions of fibers. If we limit our field of view, we can scan at around 500 microns but that is really pushing the limit. With whole removed brains, researchers potentially could scan at 250 microns resolution but 500 microns is more likely. We can do little pieces of brain in ultra high field strength machines at greater resolution (maybe 150 microns).
I think that some day we will get there but we're not particularly close to resolving individual neurons with diffusion weighted imaging.
The pasta. You mean wake up and smell the pasta.
The glorious smell of divine carbohydrates smothered in both marinara AND red sauce, nestling two bountiful orbs of meat and bread conglomerate.
Ramen brother, ramen.
Thanks for the info! I guess I should have better qualified "close", but it's not really my field, I just know a guy who knows a guy who... After reading your link, I think I vaguely remember something about the DTI being unable to resolve fibers that cross.
I'm guessing that you do your studies on a 3T...do you know how much better a 7T might be?
What resolution must we reach in order to resolve a individual fibers?
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Yes, we use a 3T. Theoretically 7Ts would be better (there aren't any 7T scanners for people that I know of) but there are some issues that engineers are still working through (signal, noise, safety, etc.).
To reliably resolve individual axons, we'd have to have a resolution of under 5 m (as I said earlier, we typically resolve 2000 m in vivo). That's a huge volume difference (125 cubic m vs. 8,000,000,000 cubic m)! We "take pictures" of the brain using voxels (volumetric pixels), so the 3D resolution is important (although, you could work on having a high in plane resolution and not worry so much about the depth - e.g., 5 m X 5 m X 50 m).
Yeah, we'd love to do individual fibers but it will be a lot of years before that happens, at least with MRI technology.
Safety, yes. I bet the heating issue would be much worse at 7T. A google turns up a few places that have a 7T
Okay, so we are waaay farther from fibers than I thought. Still, though, fascinating little discussion, thanks! I love talking to brain researchers for some strange reason.
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You're welcome. You are correct, there are a few 7T human scanners being used for research now. I hadn't checked on 7T scanners for a couple years so I guess things have changed! I'd love to get my hands on a 7T scanner. :)
I should add that 7T MR scanners are not available commercially. This means you have to have a research agreement with the manufacturer to have one (you essentially test it out for them).
There are very convincing theoretical reasons why DTI can never resolve individual axons, at least not in a non-cryogenic sample. If you want to look at individual axons you're far better off doing it the old fashioned (and considerably less sexy) way: with a microscope.
How far are they with gamma ray laser holography?
Of course, you'd have to be dead to use this yourself.
There are existing techniques that give ~tens of nanometers resolution using fluorescence microscopy (discussed in a feature in Nature Methods ). Techniques such as PALM/FPALM/STORM (developed by Betzig, Hess, and Zhuang, independently) use photoswitchable fluorophores to image and localize single fluorescent molecules with high precision then reconstruct the image from these single molecule images. Another technique, STED (stimulated emission depletion, developed by Hell) uses stimulated emission to effectively shrink the size of the point spread function of a fluorescence microscope. Yet another technique, structured illumination microscopy (developed by Gustafsson), plays tricks with moiré patterns to extend the resolution of optical microscopy. All would, in theory, be applicable on Smith's array tomography samples.
On issue with superresolution fluorescence microscopy, however, is that the spatial resolution of an image is dependent on the density of antibodies bound to the sample. The Nyquist criterion defines how frequently one must sample the underlying structure (the neuron) in order to achieve a specific spatial resolution. In this case, each antibody that binds to the neuron is one sampling event. Therefore, achieving very high resolution requires binding more antibody to the sample than typical for standard immunohistochemistry. This can be difficult, especially in samples that are embeded in resin (as is required to get the 70 nm sections used in the array tomography method), as the embeding process can drastically reduce the antigenicity of the sample.