Brain
There are dozens of other chemical neurotransmitters that are used in more limited areas of the brain, often areas dedicated to a particular function. Serotonin, for example—the primary target of antidepressant drugs and many dietary aids—comes exclusively from a small brainstem area called the raphe nuclei. Norepinephrine, which is involved in arousal, comes exclusively from a nearby small area called the locus coeruleus. Other neurotransmitters such as acetylcholine and dopamine have multiple sources in the brain, but are not as ubiquitously distributed as glutamate and GABA.
Blue Brain Project
The initial goal of the project, completed in December 2006, was the simulation of a rat neocortical column, which is considered by some researchers to be the smallest functional unit of the neocortex (the part of the brain thought to be responsible for higher functions such as conscious thought). In humans, each column is about 2 mm in length, has a diameter of 0.5 mm and contains about 60,000 neurons; rat neocortical columns are very similar in structure but contain only 10,000 neurons (and 10 synapses). Between 1995 and 2005, Markram mapped the types of neurons and their connections in such a column.