Because of the spatial proximity of the controlling alpha motor neurons in the spinal cord, to the muscles, reflexes are very fast. Often heralded as responsible for rational thought, in light of hippocampal work, we really don't know what it does. Lashley's ablation experiments on cats show that destruction of cortex results in gradual degradation in cognitive performance, a finding also born out in clinical cases with humans. Molecular advances Many fascinating and biological inventions seem to have been developed to implement the rapid information processing architecture we see in the brain. It could be a uniquely discovered process by mammals.
Myelin also appears to have been unique and important evolutionary advancement.
In invertebrates, fast signalling is only achieved by creating extremely large axons, since resistance is inversely proportional to the cross-section of the conducting medium. In mammals, the introduction of a new glial cell which wrapped itself around the axons, myelin, allowed signalling speed to increase by orders of magnitude, and also allowed neurons and connections to become extremely small, allowing for the dense packing to take place. The Extropians are a group dedicated to boundless transhuman expansion. This is their view of the future evolution of humanity.