Early on the morning of April 16, 1998, dozens of snails and fish will go where only a few men and women have gone before: into outer space. The snails and fish will travel aboard NASA's Space Shuttle Columbia, as part of a research project funded by the National Science Foundation (NSF) to study the development of gravity sensors in space by animals in the early stages of life.
The snails and fish will fly aboard Neurolab, a shuttle research mission dedicated to the study of the life sciences. Neurolab will focus on the most complex and least understood part of the human body -- the nervous system --which faces major challenges in space.
Gravity sensing systems have the same basic structure in all vertebrates, whether fish or humans. The gravity-detecting organ is lined with sensory cells that send signals to the brain when they are "triggered" by small, rock-like particles of calcium carbonate, referred to as statoliths in snails and otoliths in fish (and in humans). In humans, this system is a component of the inner ear.
"Gravity is always present on earth, so it's been hard to explore its role in development and in controlling movement," says Christopher Platt, program manager in NSF's division of integrative biology and neuroscience, which funded the aquatic experiments. "Neurolab allows unique tests that will shed light on how gravitational sensors work. These studies may tell us how exposure to lack of gravity may lead to abnormalities in the otolith organs, relevant to long-term space flight and to certain kinds of posture and balance problems in people on Earth."
Other benefits of the aquatic studies aboard Neurolab are development of an electrode that offers potential use as a connection to the nervous system in people with deafness caused by hair cell damage. The electrode might also someday be used as an interface to signal motor prostheses how and when to move.
Tracking the progress of the snails and fish flying aboard Columbia will be scientists on The Aquatic Team, as they're known to shuttle crewmembers. Researcher Michael Wiederhold of the University of Texas Health Science Center at San Antonio will monitor freshwater snails and swordtail fish in the beginning stages of their development into adults.
Wiederhold hopes to learn what physiological changes occur in the components of the gravity sensors of animals in space, whether signals sent from the inner ear to the brain are altered, and if alterations do occur, whether behavior of the animal changes. Upon return from their flight in space in Neurolab, the freshwater snails and swordtail fish will be compared to a control group on Earth to determine whether the size of their statoliths and otoliths increased while they were in "microgravity." On Earth, the pull of gravity eventually signals developing statoliths and otoliths to stop growing. "In space, however," says Wiederhold, "without this signal, they should develop to a larger size than they do on Earth. And if indeed they increase in size, how will that affect these animals?"
Scientist Steven Highstein of the Washington University School of Medicine in St. Louis, Missouri, will also study aspects of the inner ear, but his research involves the inner ears of astronauts flying aboard Columbia, as well as those of oyster toadfish aboard Neurolab.
Editor's Note: For more information, see:
* Neurolab Mission Home Page -- http://neurolab.jsc.nasa.gov/
* Neurolab Online (for students and teachers) -- http://quest.arc.nasa.gov/neuron/
* Neurolab Crew Page -- http://www.psu.edu/nasa/
The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.
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