It works like this: You take a brain, or parts of that brain, and you dissolve it in detergent, which destroys the cell membranes but keeps the cell nuclei intact, so you end up with a suspension of free nuclei that looks like this, like a clear soup.
Ovako nekako ide: Uzmete mozak, ili dijelove mozga, i otopite ih u deterdžentu, što uništi membrane stanica ali ostavi stanične jezgre netaknutima, pa dobijete otopinu slobodnih jezgara koje izgledaju ovako, poput čiste juhe.