Given that this blog is named after a neuroscience term, and the fact that I am a neuroscientist, I figure it's probably high time that I post something on neuroscience.
A team of scientists at Cold Spring Harbor Laboratory have developed a technique that allows them to image cells that are dividing the the brains of live humans. It has been known for some time that some parts of the brain actually add new neurons in adults, till the day we die. This has been shown by using a trick to label new DNA.
When a cell divides, the DNA strands split in two. The two strands split apart, and the cell splits in two. Meanwhile, the missing strand is replicated by an enzyme using free floating nucleotides (the ATGC's that everyone knows). The final product is two cells with exact copies of the DNA.
The trick is to give animals a compound that mimics one of the nucleotides (T usually). The compound gets taken up by any new cells that are making new DNA. This compound has something unique about that can be identified later. And by later, I mean once the animal or human has died and it's brain has been sliced into very thin sections and treated with all sorts of chemicals.
What the CSHL team did is use a trick of magnetic resonance imaging that up to this point had not been identified. It is possible to take images of the inside of alive, awake humans without any invasive procedures whatsoever. I won't explain How MRI works, mostly because I am no expert by far, but check out Wikipedia and How Stuff Works if you're curious. Basically, these broke down the various spectra of various cell types in the brain and identified a particular peak that is found only in cells that divide. The did this using cells isolated from mice brains, so they new what kind of cell they were looking at.
Next, they looked at the areas known to have dividing cells in the brains of rats and humans. Not dead sliced up brains, but whole brains still in the heads of their fully-alive owners. Sure enough, the band they saw in the mouse cells is also in these areas. Pretty cool.
They say this could be used clinically, but I see some very exciting possibilities for research. Many neuroscientists are interested in what controls the rate of neuron addition. This technique will allow scientists to test various treatments effects on cell proliferation in the same individuals over time. Very cool.
If you have access to Science, you can read their original paper here.