Susan Greenfield's The Brain - A Guided Tour is an excellent introduction to neuroscience for the general reader. The book arose from Greenfield's 1994 Royal Institution Christmas Lectures - the annual series of science lectures to older children and teenagers spread over five days. The material has been expanded and re-worked for adult readers, but the five long chapters reflect the original five lectures.
The first chapter, Brains Within Brains puts things in context, describing the history of 'brain science' and how our knowledge of our most important organ has grown. There is some discussion of the anatomy of the brain, showing how there are distinct regions rather than a single amorphous mass of grey matter. Along the way many of the tools currently used to examine the brain, such as MRI scans, are introduced.
The second chapter, Systems of Systems, looks at the way different functions - such as vision, hearing and language - are organised. Greenfield does a good job of describing how brain injuries victims are used as experimental subjects. Damage to different physical areas are correlated with their effects, throwing light both on the localisation of function, (such as speech), and on the degree of plasticity, (the degree to which other parts of the brain can take on the work of the areas which have been damaged). It's fascinating stuff, of course, and Greenfield explains it clearly and simply without pretending that we understand everything that's going on.
Pulse, Impulse, the third chapter, looks in greater detail at the physical structure of the brain. Neurons, dendrites, axons and so on are described in some detail. The role of neuro-transmitters is also discussed, particularly with respect to ecstasy, Prozac and the like. The chapter ends on a tantalising note: why do drugs effect mood? Why should a particular set of molecules make you feel good, bad or too indifferent to care?
Chapter four is Cells Upon Cells, and looks in more detail at the development of the brain in the foetus. This is not purely an internal biological process but is intricately linked to the external environment. The important point is that we are not simply the product of our genes (no matter how selfish you think they are). The development of our brains, and our abilities, depends on genes, nutrition, oxygen, external stimuli and a host of other factors.
The final chapter, With Mind In Mind, looks at the mysteries of consciousness and learning. This is, perhaps, the most difficult material in the book, particularly when describing the electro-chemical processes that are permanently taking place inside our heads. On the other hand these are difficult, indeed central, questions - consciousness is what makes us human but we still have little agreement as to how the physical brain becomes the non-physical mind.
Neuro-science is one of the most bitterly contested areas of scientific research. There are competing theories in every part of the subject. After all, our views on what it is to think, learn and be conscious have direct political consequences. As the current controversies about evolutionary psychology show, public policy in education, for example, is clearly underpinned by theories of intelligence and learning. These are both ideological and scientific questions.
As a first introduction to the subject, The Human Brain is readable, interesting and poses as many questions as it answers.
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