Since the last edition of this textbook, the field of Neurology and the Neurosciences has witnessed remarkable advances in the technologies available for the study of the brain and our concepts about the nervous system and its diseases. There has been progress in our ability to modify, prevent or treat these disease processes and to evaluate clinical outcomes, and in the resources available to handle and disperse data. There is, however, always a competition between the advancement of knowledge and the challenges of disease. We face challenges that demand that we put these advances to good use.

This introduction provides a brief, and necessarily incomplete, overview of some of the advances, and the many remaining challenges, for the study and treatment of diseases of the nervous system. A number of new therapeutic strategies have already been developed, and are already impacting on the quality of life of those with neurological disease. Many new treatments, both symptomatic and disease-modifying, are in the developmental pipeline. With the delineation of the human genome in 2001, a particular problem has emerged: the need to delineate protein production (proteomics) and protein modifications on a cellular basis. ‘The emerging challenge in understanding the pathogenesis of the neurodegenerative disorders will be to characterize and elucidate aberrant protein interactions in the affected cells’ (Martin, 1999). Future efforts will be focused on determining the tertiary structure of proteins which is currently determined using X-ray crystallography and nuclear magnetic resonance. Because of their relatively low through-put, complexity and high cost, these techniques have not generally been used for therapeutic targeting in drug discovery programmes. Recent technological advances, coupled with the information from human genome sequencing, are beginning to enable construction of a database to predict protein structure from sequence, and may be relevant for up to one-third of all gene targets (Christendat et al., 2000).

Global challenges in the developed and developing world

The world's aging population is increasingly affected by both acute and chronic neurological diseases. These include cerebrovascular disease, Alzheimer's disease and other dementias and Parkinson's disease. In the USA, the number of the very old (older than 85) is expected to increase sevenfold, from 2 million in 1990 to 14 million in 2040 and is increasingly vulnerable to chronic neurodegenerative disorders.