throughout the mammalian brain = ?

Does "throughout the mammalian brain" refer to the fact that vital GABA cells (who dodge in the tangle formed by axons and dendrites) spread throughout the mammalian brain ?

Context:

Neuroanatomists have been trying to map the brain's circuitry for well over a century, but the organ's astonishing complexity -- anatomical and functional -- has insured that progress has been slow. Researchers have been able to map the entire set of circuits in the roundworm C. elegans. But that humble creature has only 302 neurons. The brains of mammals have millions of neurons, and within the tangle formed by their projections, called axons and dendrites, one finds those vital GABA cells, which until now could not be identified in any consistent way globally, throughout the mammalian brain.

More:

http://www.sciencedaily.com/releases/2011/09/110921132342.htm