Neuroscientists have the daunting task of deciphering the
mystery of this most complex of all machines: how as many as a trillion nerve
cells are produced, grow and organize themselves into effective, functionally
active systems that ordinarily remain in working order throughout a person’s
lifetime. The motivation of researchers is twofold: to understand human
behavior better—from how we learn to why people have trouble getting along
together—and to discover ways to prevent or cure many devastating brain disorders.
The more than 1,000 disorders of the brain and nervous system
result in more hospitalizations than any other disease group, including heart
disease and cancer. Neurological illnesses affect more than 50 million
Americans annually at costs exceeding $400 billion. In addition, mental
disorders, excluding drug and alcohol problems, strike 44 million adults a year
at a cost of some $148 billion. However, during the congressionally designated
Decade of the Brain, which ended in 2000, neuroscience made significant
discoveries in these areas:
Genetics. Key disease genes were identified that underlie
several neurodegenerative disorders—including Alzheimer’s disease, Huntington’s
disease, Parkinson’s disease and amyotrophic lateral sclerosis. This has provided
new insights into underlying disease mechanisms and is beginning to suggest new
treatments. With the mapping of the human genome, neuroscientists will be able
to make more rapid progress in identifying genes that either contributes to
human neurological disease or that directly cause disease. Mapping animal
genomes will aid the search for genes that regulate and control many complex
behaviours.
Brain Plasticity. Scientists began to uncover the molecular
bases of neural plasticity, revealing how learning and memory occur and how
declines might be reversed. It also is leading to new approaches to the
treatment of chronic pain.
New Drugs. Researchers gained new insights into the mechanisms
of molecular neuropharmacology, which provides a new understanding of the
mechanisms of addiction. These advances also have led to new treatments for
depression and obsessive compulsive
disorder.
Imaging. Revolutionary imaging techniques, including magnetic
resonance imaging and positron emission tomography, now reveal brain systems
underlying attention, memory and emotions and indicate dynamic changes that
occur in schizophrenia.
Cell Death. The discovery of how and why neurons die, as well
as the discovery of stem cells, which divide and form new neurons, has many clinical
applications. This has dramatically improved the outlook for reversing the
effects of injury both in the brain and spinal cord. The first effective
treatments for stroke and spinal cord injury based on these advances have been
brought to clinical practice.
Brain Development. New principles and molecules responsible
for guiding nervous system development now give scientists a better
understanding of certain disorders of childhood. Together with the discovery of
stem cells, these advances are pointing to novel strategies for helping the
brain or spinal cord regain functions lost to diseases. Federal neuroscience
research funding of more than $4 billion annually and private support should
vastly expand our knowledge of the brain in the years ahead.
This book only provides a glimpse of what is known about the
nervous system, the disorders of the brain and some of the exciting avenues of
research that promise new therapies for many neurological diseases.
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