I mean, it's not like it's a novel procedure or anything. This is basically how all brains are sectioned for immunohistochemistry.
A quick search turned up this protocol, labeled 2006: http://sydney.edu.au/medicine/pharmacology/CRGweb/internal/l...
I don't know when it was first used, it's one of those protocols that every lab has sitting in an ancient three-ring binder. The procedure is essentially the same everywhere, with minor variations depending on the tissue you're working with, the stains, etc:
1. Knock the animal out somehow (usually isoflurane or similar)
2. Perfuse with Phosphate-buffered saline (PBS) followed by 2-5% Paraformaldehyde (PFA). You can also use glutaraldehyde, which is better for EM, while PFA is usually better for histochemistry
3. Rinse in PBS for a while
4. Drop the brains into sucrose solutions, let them sit there until they sink. Usually labs will have a few sucrose baths they like to use (e.g. start in 10%, then switch to 30%). Sucrose is the cryoprotectant here
5. Dunk in liquid nitrogen, coat with OCT, mount on cryostat and start sectioning
6. Go about your business staining, etc
The only novel thing here, really, is that they perfused the cryoprotectant instead of just letting the brains sit in it for a few days. Letting a rabbit brain soak up sucrose likely takes longer than a mouse, so perfusing would definitely speed up that step.
But it's a rather moot point, since fixed brains can chill in refrigerated PBS for a month or two. There's no rush once it's fixed ... that's the point of fixing. I'm with the other folks, this was really just a grab at some money imo. And fancy headlines. There is nothing interesting here.
Credentials: worked in neuroscience wet-lab for 5 years.