First map of the human brain reveals a simple, grid-like structure | Hacker News Reader

First map of the human brain reveals a simple, grid-like structure

extremetech.com

62 pointsevo_910 comments

Stupid extremetech spam, please do not submit rubbish like this.

Actual source is http://www.nih.gov/news/health/mar2012/nimh-29.htm as submitted in http://news.ycombinator.com/item?id=4309598

I really think it's time we on HN require linking to the original article unless there is significant value/commentary added.

In fact, I'm in favor of flagging this one as a duplicate and moving all 50 points to the other thread. I'd love to see this become policy.

Without such a policy, many blogs have an incentive of taking original links posted on the new page, quickly writing a dumbed down summary in 30 minutes and submitting it as a new story. This is undesirable behavior that needs to be nipped in the bud.

Any blog post that essentially just summarizes another one, or worse yet dumbs it down, is spam and should be treated as such.

As seen a few hours ago... http://news.ycombinator.com/item?id=4309598

I am not a brain scientist and I'm sure they've considered this at least at some level of depth: But what are the chances that we are just seeing this as a side-effect of the tool being used to observe the brain?

This technology is being explored since the 80s [1] and has been the source of similar images since at least 2008 [1].

Each line is the path traced by a water molecule (layman's explanation, please correct me). DSI is a variant of MRI that seems to have been developed precisely to map small crossing fibers, so that would be a huge failure.

[1] http://en.wikipedia.org/wiki/Diffusion_MRI [2] http://www.technologyreview.com/news/410560/the-brain-unmask...

Ex-Neuroscientist here. Your explanation is quite accurate, though I believe they use a more modern variant called Diffusion Tensor Imaging. The idea of MRI is that you put the brain into a huge magnetic field, switch the magnet of and count how long it takes for the nuclear spin to jump back to random states in different areas of the brain - this time is specific to each different atom and allows for an estimate of the concentration of different atoms (like water). In DTI, the hypothesis is that water molecules line up with the neurons axons (the long cables that connect neurons to distant other neurons). If change the direction of the magnetic field gradient a couple of times, you don't just get one value per voxel (how much water is in there), but slightly different values for each direction. The highest value is _probably_ the direction of alignment of the majority of axons in that voxel.

The problem is not the tool, but the statistical analysis of the data, which depends on a lot of parameters, and the number of different gradient directions, which are usually orthogonal, hence favouring orthogonal neuronal connections and discounting those that are diagonal to the gradient directions. You have to correct for this in the analysis, but it's very hard to do, and mostly guesswork. Which coincides my personal evaluation of the entire study: guesswork.

I don't know if "grid" is the right word; from the video it looks more like a jumble of IDE cables. Very cool though! Understanding the brain is one of the most important tasks we have yet to conquer.

The first map...really. Also 'the location of individual memories' haven't been pinpointed. This guy's in no position to be reporting articles on brain science.

The article and its title are misleading as they give the impression that this map gives the whole truth. It looks to me the equivalent of showing a map of the connections on a computer motherboard and not mentioning that there's a lot more going on, e.g. in the chips.

On the complexity of single neurons it is worth to read Koch's research "The role of single neurons in information processing"

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