Introdtiction 
for Duchenne and Becker muscular dystrophy. 
These are X-linked recessive disorders that, in the 
more severe (Duchenne) form lead inexorably 
from muscular weakness to muscular atrophy and 
finally death. The extreme size of this gene (it 
comprises about 1 percent of the X chromosome 
and almost 0.1 percent of the total human ge- 
nome) renders it especially vulnerable to muta- 
tion, and in many of the identified mutations, the 
protein encoded by the gene, dystrophin 
(which appears to be critical for coupling muscle 
excitation and contraction), is either absent or 
markedly deficient. 
Some years ago the general location of the gene 
responsible for the severe neurological disorder 
known as Huntington's disease (HD) was deter- 
mined using RFLPs, as discussed in the section on 
genetics. Although the HD gene itself has so far 
eluded us, there is every reason to be optimistic 
that within a year or two it will be identified and 
cloned. In the meantime, the relevant RFLP has 
provided a useful marker for identifying carriers 
of the disordered gene. There is similarly reason 
for optimism that in the near future the genetic 
basis for the two major affective disorders, manic 
depression and schizophrenia, will be eluci- 
dated. Careful studies of family histories and of 
identical twins raised apart have clearly estab- 
lished that both illnesses have an important ge- 
netic component, and while neither is probably 
due to a single genetic mutation, RFLP analysis 
and other genetic approaches should reveal the 
genes involved. That such complex behavioral 
Investigators in the Neuroscience Program 
Adams, Paul R., Ph.D. 
Aldrich, Richard W., Ph.D. 
Anderson, David J., Ph.D. 
Artavanis-Tsakonas, Spyridon, Ph.D. 
Axel, Richard, M.D. 
Corey, David P., Ph.D. 
De Camilli, Pietro, M.D. 
Evans, Ronald M., Ph.D. 
Goodman, Corey S., Ph.D. 
Horvitz, H. Robert, Ph.D. 
Huganir, Richard L., Ph.D. 
Hurley, James B., Ph.D. 
Jahn, Reinhard, Ph.D. 
Jan, Lily Y., Ph.D. 
Jan, Yuh Nung, Ph.D. 
Jessell, Thomas M., Ph.D. 
Kandel, Eric R., M.D. 
Lerner, Michael R., M.D., Ph.D. 
Miller, Christopher, Ph.D. 
Movshon, J. Anthony, Ph.D. 
disorders might yield to this type of approach was 
unthinkable only a decade ago; as noted in the 
section on genetics, nothing serves to emphasize 
more dramatically the power of the new genetics 
or the exciting possibilities it portends. 
The dramatic advances in cellular and molecu- 
lar neuroscience should not obscure the fact that 
the distinctive role of the nervous system in the 
economy of an organism is its capacity to inte- 
grate sensory information that is received (both 
from within and from outside the body) and to 
organize it into patterns of behavior that allow 
the organism to respond to changes in its environ- 
ment in appropriate ways. And for human beings, 
it is through the nervous system that we learn 
both from personal experience and the accumu- 
lated wisdom of previous generations not only 
how to survive but how to enjoy and profit from 
the richness of mental experience and meaning- 
ful social interactions. To understand all this we 
will need to learn a great deal more about the 
activities of large populations of nerve cells, 
about the computational capacity of complex 
neural networks, and about the extraordinary 
ways in which the human brain, with its 100 bil- 
lion or more neurons and its more than 1 trillion 
synapses, receives and processes information. We 
are at the threshold of being able to understand 
the logic of the simplest organisms at both the 
molecular and systems levels; the exploration of 
human behavior in these same terms stands as 
perhaps the greatest challenge to modern 
science. 
Reed, Randall R., Ph.D. 
Reichardt, Louis P., Ph.D. 
Rosenfeld, Michael G., M.D. 
Rubin, Gerald M., Ph.D. 
Sakmar, Thomas P., M.D. 
Scheller, Richard H., Ph.D. 
Sejnowski, Terrence J., Ph.D. 
Siegelbaum, Steven A., Ph.D. 
Steller, Hermann, Ph.D. 
Stevens, Charles F., M.D., Ph.D. 
Struhl, Gary, Ph.D. 
SUdhof, Thomas C, M.D. 
Tanabe, Tsutomu, Ph.D. 
Tsien, Roger ¥., Ph.D. 
Yau, King- Wat, Ph.D. 
Yellen, Gary, Ph.D. 
Ziff, Edward B., Ph.D. 
Zipursky, S. Lawrence, Ph.D. 
Zuker, Charles S., Ph.D. 
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