Modern brains have an ancient core

Multifunctional neurons that sense the environment and release hormones are the evolutionary basis of our brains. Hormones control growth, metabolism, reproduction and many other important biological processes. In humans, and all other vertebrates, the chemical signals are produced by specialised brain centres such as the hypothalamus and secreted into the blood stream that distributes them around the body. Researchers now reveal that the hypothalamus and its hormones are not purely vertebrate inventions, but have their evolutionary roots in marine, worm-like ancestors. Hormone-secreting brain centres are much older than expected and likely evolved from multifunctional cells of the last common ancestor of vertebrates, flies and worms. "Vertebrate-type hormones were found in annelid worms and molluscs, indicating that these centres might be much older than expected." "So far we have always understood the brain as a processing unit, a bit like a computer that integrates and interprets incoming sensory information. Now we know that the brain is itself a sensory organ and has been so since very ancient times."