If you want to study the effects of drugs or transplants on the brain without operating on the real thing, you typically have to break out some microelectronics and build a model yourself. Not exactly convenient or cheap, is it? If Brown University scientists have their way, however, just about any lab could make some simulated brain matter of their own. They've developed a technique that creates a miniature brain (really, a bundle of electrically active neurons) by extracting cells with a centrifuge and seeding a cell culture. So long as you have two to three weeks and 25 cents' worth of material, you'll have a complex, three-dimensional neural network to tinker with.
This isn't a live, thinking brain (arguably a good thing for tests), but it's close enough that you could transplant and experiment with cells and expect to get realistic results. The discoverers hope that this will eventually let many labs test treatments and research neurological development, especially the not-so-dedicated outfits that can't justify buying expensive gear to answer a few questions. You could see more medical breakthroughs simply because more scientists would be proving their own theories, rather than leaning on others for help.
[Image credit: Hoffman-Kim lab/Brown University]