The "brains" don't have cogitation abilities, but they more closely resemble the cell makeup and structures of real brains than do 2D tissue cultures and have several properties that make them similar to real brain tissue for research purposes, including multiple cell types that are able to form synapses, or electrical connections to each other.

Measuring just a third of a millimeter wide, the brains are naturally shaped, with a similar density to rodent brains. They don't require the microelectronics or tissue culture facilities used in other techniques, or contain artificial scaffolding like collagen, while still forming an extracellular matrix of molecules secreted by the cells.

The structures are formed by first centrifuging tissue samples to obtain the right makeup of cells, then culturing those cells in special agarose molds created with technology developed by MicroTissues, Inc. – a startup founded by Jeffrey Morgan, one of the Brown researchers on the project.