  Despite differences in brain sizes and cognitive niches among mammals, their
cerebral cortices posses many common features and regularities. These
regularities have been a subject of experimental investigation in neuroanatomy
for the last 100 years. It is believed that such studies may provide clues
about cortical design principles and perhaps function. However, on a
theoretical side there has been little interest, until recently, in studying
quantitatively these regularities. This article reviews some attempts in this
direction with an emphasis on neuronal connectivity. It is suggested that the
brain development is influenced by different, conflicting in outcome,
functional/biochemical constraints. Because of these conflicting constraints,
it is hypothesized that the architecture of the cerebral cortex is shaped by
some global optimization plan.
