Live now: Human brain cut into thin slices | Hacker News Reader

Live now: Human brain cut into thin slices

thebrainobservatory.ucsd.edu

28 pointshuangm19 comments

Hi everyone, I'm the girl that works at the brain observatory that ddemchuk mentioned. I just wanted to say that it's really amazing to see so many people interested in our project, so thank you! Also, I thought you might be interested in a rough overview of the process. As was already mentioned, we've been preparing HM's brain since Feb in order to be able to freeze it without actually damaging any of the tissue. We embedded the brain in a block of gelatin to ease the cutting process, and we froze the block yesterday. The sections do wrinkle up on the microtome, but both the gelatin and the fact that we cut at a very low temperature (-40C) allow us to maintain the structural integrity of the tissue (and yes, we do use a paintbrush to retrieve the sections). Hope that cleared some stuff up! Thanks again for watching!

Very interesting stuff. Thanks for sharing the details with us.

This isn't just any brain, it's HM's brain[1], who possibly contributed more to neuroscience than any other single patient.

[1] http://en.wikipedia.org/wiki/HM_(patient)

It's going on now and for the next ~50 hours. The brain belongs to H.M., the guy that the movie Memento is 'based on'. When he was alive, he could not create new short-term memories. He's been the subject of study for years until he passed in 2008.

Watching this is a bit weird, it's reminiscent of a deli meat slicer.

This may be picking nits, but HM could not create new long term episodic memories. He could use short term memories and learn new skills, but he couldn't remember times, places, and events.

He could learn declarative knowledge like that, but not very well. http://www.npr.org/templates/story/story.php?storyId=7584970 - Dr. MILNER: How about 1963? Someone was assassinated.

H.M.: He'd been a president.

Dr. MILNER: That's right.

H.M.: And he was assassinated.

Dr. MILNER: What was his name?

H.M.: He had been, like you said, he had been a president.

Dr. MILNER: His initials are JFK.

H.M.: Kennedy.

Dr. MILNER: That's right. What was his first name?

H.M.: John.

More about HM, whose brain it is: http://www.pbs.org/wgbh/nova/sciencenow/0407/02-cork.html

You can watch a ten-minute video feature at the site below: http://www.pbs.org/wgbh/nova/sciencenow/video/0407/i02.html

Note that within the first few minutes of that video, they show the brain already sliced up, and speak about it in the past tense; there's also a cut-and-died slice in a photo of the already-dissected brain on the first link...

I first watched that feature a few months ago, and from what I could gather, the episode was originally aired on 2009 August 25; anybody know what gives?

I'm sure they know what they are doing but the way that the slice is extracted after each pass seems really problematic to me. It looks like the slice "bunches up" and they extract it manually with some kind of blunt instrument. Wouldn't that result in a lot of unintended tearing and deforming of the slice? Perhaps someone who has used a microtome before can explain.

Are they saving the slices or just photographing each layer as it's cut down?

I'm pretty sure they just care about the photographs at this stage.

That's what I thought as well... I don't think the slices themselves would be much (if any) more useful than just dissecting the brain normally...

Watch the video link posted by Ezra http://news.ycombinator.com/item?id=973677 and you can see what they do with each slice.

They store it in a tray with square holes (all bunched up). Later they remove it, wash it, mount it on glass, and stain it. Then it goes under an automatic microscope that scans it.

Wow, thanks! From the way the slices were bunched up I (wrongly) assumed they were basically getting thrown away. But I guess not!

I believe they will preserve the slices cryogenically.

http://thebrainobservatory.ucsd.edu/hmblog/?p=66

I am not an expert, by any means, but my fiancée, a med student, says the brain is encased in and has had its water content replaced by paraffin. Paraffin doesn't stick to itself very much, so the sample is not likely to be damaged by the bunching. The "blunt instrument" you see is probably just a soft brush.

This is one of those things that I never thought the internet would bring you: Real time slicing of a brain. Crazy. It's amazing to think of where we will be in another 10-30 years.

By then you'll be able to watch them slice up and scan your own brain, as they transfer your personality to a digital substrate. I hope.

Amazing. As an additional note: their whole website is really beautifully designed...

My girlfriend lives with a girl who works at that lab and is probably working on that brain right now. She's explained a lot of the process to me, it's pretty fascinating stuff. I think they save every 10 slices or so, and the brain has been being prepared for like 6 months so as to allow for them to do the slicing like they do. They then go on to create the slides that will be digitally archived for other labs to study.

Reply on news.ycombinator.com