The human brain has been studied for millennia, but in the past decades huge advances have occurred in neurology that have allowed scientists to reassess what we really know about the least understood part of the human body. Using technology that allows researchers to see deeper into the physical organ and record new discoveries, the latest theories affect not just our understanding of biology but also raise questions concerning consciousness, the mind and neuro-plasticity.We can now observe the activity of the brain as it performs different functions; with scanning technology we can chart the neural pathways and devise maps. The explorations have revealed surprising results. ''The Britannica Guide'' series offers an essential introduction to many of the key issues of our times. Clear, accurate, and meticulously researched the series gives both the background and analysis for when you need to know for sure what is really happening in the world, whether you are an expert, student or traveller