Olfato

A R E P O R T F R O M T H E H O WA R D H U G H E S M E D I C A L I N S T I T U T E

SEEING,
HEARING,

SMELLING

AND

THE WORLD
NEW FINDINGS HELP SCIENTISTS MAKE SENSE OUR SENSES
OF

The Howard Hughes Medical Institute was founded in 1953 by the aviatorindustrialist Howard R. Hughes. Its charter reads, in part: “The primary purpose and objective of the Howard Hughes Medical Instituteshall be the promotion of human knowledge within the field of the basic sciences (principally the field of medical research and medical education) and the effective application thereof for the benefit of mankind.”

This is the fifth in a series of reports about biomedical science. For further information, please contact the Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase,Maryland 20815-6789
© 1995 Howard Hughes Medical Institute

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t is a pleasure to introduce the latest of the biomedical research reports that the Howard Hughes Medical Institute publishes for general readers. Seeing, Hearing, and Smelling the World, like the four previous publications in the series, takes us to the frontiers of science. It guides us ona journey into the fascinating world of the senses and the nervous system, where researchers are working to understand problems of great potential benefit. The most routine, everyday occurrences, such as recognizing a friend on the street and exchanging greetings, demonstrate the biological complexity of the puzzles that scientists are attempting to solve. Although such encounters seem simple,they require hundreds of millions of cells to act in precise ways to receive the sights and sounds and translate them into electrical impulses. These impulses flow through the nervous system to carry the messages to the brain, where they can be understood and acted upon at astonishing speed. Centuries of effort by thousands of scientists in laboratories throughout the world have been required tobring us to our current, deepening understanding about how we hear, see, and smell. Thanks to the new analytical tools provided by molecular biology, progress toward understanding the senses and the nervous system has been rapid during the past decade. Indeed, many neuroscientists believe that biomedical science is poised to make substantial progress toward understanding how the brain works, not onlyin terms of the senses, but also complex functions like learning and memory. It is an exciting prospect. This series is published by the Institute as a public service in order to make the results of current biomedical research available to readers who are not scientists. It is clear that a basic grasp of biology is increasingly essential for citizens who have to make difficult decisions abouthealth care, drug abuse, the environment, and other critical issues. Teachers are particularly enthusiastic about these reports, and surveys tell us that they preserve their copies and use them year after year. Nearly 4,000 class sets have been requested by high school, college, and even medical school teachers in the United States and abroad; altogether, more than 400,000 copies of the publicationshave been printed. The Institute’s interest in science education continues to deepen and its commitment to education reform to grow. Its grants program, which was established in 1987, has now become the largest private science education effort in U.S. history. Through its financial support and other activities, the Institute is seeking to make science come alive for today’s students, which isexactly what we hope Seeing, Hearing, and Smelling the World will do.

Purnell W. Choppin, M.D. President Howard Hughes Medical Institute

S EEING , H EARING , AND S MELLING THE W ORLD

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Laboratory of Richard Masland, Massachusetts General Hospital

A nerve cell that can detect in what direction an object is moving branches out to make contact with many other cells in a rabbit’s...