Neuroanatomy is the study of the anatomical organisation of the brain. Reciprocal communication between the brain and the cardiovascular system is important in sustaining neurobehavioral states that allow organisms to cope with their environment. Furthermore, in vertebrate animals, the routes that the myriad nerves take from the brain to the rest of the body, and the internal structure of the brain in particular, are both extremely elaborate. As a result, the study of neuroanatomy has developed into a discipline in itself, although it also represents a specialisation within neuroscience. This book briefly covers the neuroanatomy of the vagal circuit, the functional significance of tonic cardiac vagal function and ways of quantifying this measure for research purposes. Also examined are the fibre composition and functional topography of peripheral nerves, and innovative methodologies that facilitate measurements of nerve fibres. This book contributes new insights to the controversial discussion about neurotrophin effects on different cell populations and at different time points in retinal programmed cell death (PCD). Other chapters in this book provide a comparative overview of the distribution of orexin cells and fibres across the brains of vertebrates in relation to function, the neuroanatomical structures and autonomic nerves involved in headaches and a re-evaluation of the structure of the human anterior olfactory nucleus, with an updated description of this structure in the normal human.