Neurolab Becomes Centerpiece of NIH-NASA Collaboration
By Josť Alvarado
On the Front Page...
Like Columbus' maiden voyage that yielded the discovery of the New World, scientists from NIH and NASA expect that collaboration between the two agencies in the Neurolab program will open up a new frontier in space exploration and neuroscience.
Last April's launch of mission STS-90 on space shuttle Columbia initiated a joint effort between NASA and various national and international agencies, with solid support from NIH, to take the study of the brain and neuromuscular system into a new and unfathomed stage of development. The Neurolab flight was the third space shuttle mission dedicated to life science research, but it was the first mission to focus distinctly on how the neurological system responds to the challenges of space flight. Neurolab is the biggest cooperative endeavor between NIH and NASA to date.
During the early years of NASA's manned space flight program, efforts in the life sciences were driven by operational medicine and biomedical support of short duration ventures such as the Mercury and Gemini missions. During these flights, according to NASA literature, no significant problems arose regarding sensory system function. However, during the Apollo missions, a number of astronauts reported mild to severe motion sickness, and in the early 1970's NASA initiated studies of the illness. More recently, attention has been devoted to other physiological and behavioral changes that occur as a result of space flight.
The growing emphasis on efficiency in government may have served to promote greater interactions between NASA and NIH, considering the importance of the medical spin-offs to be obtained from experiments done in space. Since the early 1990's, NIH has collaborated with NASA's life and biomedical sciences applications division in a number of ground-based and space-bound projects, which include NASA-developed lasers for the early detection of eye disease and improved means of measuring intracranial pressure that may benefit victims of trauma, as well as astronauts. NASA bioreactor technology has also been used by NIH to grow tissue samples for use in AIDS research. Current research in neurobiology by NIH and NASA is an outgrowth of a 1990 "Decade of the Brain" presidential declaration.
Astronauts Land on NIH
Neurolab astronauts -- clad in their blue jumpsuits -- visited NIH's Natcher auditorium on July 16 and presented an overview of experiments carried out on their mission. During 16 days, beginning Apr. 16, the crew conducted 26 in-flight experiments using a number of animal species including fish, rats, mice, snails and crickets. They worked in a reusable laboratory module called Spacelab -- carried in the middeck area of the space shuttle and about the size of a bus -- that allowed scientists to conduct experiments under microgravity conditions while orbiting Earth.
"These experiments are really more exploratory than hypothesis-driven research," explained Dr. William Heetderks of NINDS, who is one of NIH's Neurolab project managers. "It's akin to Columbus' voyages of exploration; new knowledge as well as new questions can be attained. It departs from traditional answer-directed research. Neurolab is like Columbus exploring uncharted waters."
Added NIA's Dr. Andrew Monjan, "Most research is serendipitous. If it were totally predictable, then research would not be necessary. Space may not be the final frontier, but it certainly is a challenging frontier."
Neurolab focuses on the most complex and least understood part of the human body -- the nervous system. Consisting of the brain, spinal cord, peripheral nerves and sensory organs, this system faces major challenges in space. The nervous system controls blood pressure, maintains balance, coordinates movements and regulates sleep. All are affected by space flight.
Astronaut and mission specialist Richard M. Linnehan described Neurolab as "the most complicated mission NASA has ever flown" and a "high quality flight." He narrated a 15-minute film describing work before, during and after the mission, that was shown to an audience that packed Natcher auditorium and a conference room above it where NIH'ers viewed the event on video. The movie showed revealing shots of the space shuttle launch as seen from inside the cockpit, as well as rapport between crew members during experiments. Astronaut Kathryn P. Hire, flight engineer for the mission, characterized living in the weightless environment as "scuba diving without the equipment."
Astronauts conducted experiments on how simple, everyday movements can be modified by an environment devoid of gravity. On Earth, the brain integrates information from the eyes and inner ear, as well as from nerves in the joints and muscles, to make smooth, accurate movements. In space, however, the inner ear no longer provides the brain with useful information about "up" or "down," and the nerves in the joints are sensing the movements of weightless limbs. The astronauts' nervous systems must adapt so they can function effectively.
Dave Rhys Williams, a physician and Canadian Space Agency astronaut, participated in hand-eye coordination experiments, wearing a head-mounted virtual environment generator -- developed by CSA -- that tested how he could maintain orientation in space. He initially felt the "same as being on the ground," but as the experiment progressed, he felt "something had changed since the beginning of the mission. Part of the excitement of being in orbit is seeing how our own bodies change during the mission."
The scientists studied how much of normal nervous system development is preprogrammed in human genetic code, and how much can be modified by different environments. The fact that people can function well in space shows that the nervous system can compensate effectively. Neuronal plasticity accounts for this phenomenon, in which neurons react to changed conditions by making new connections in different forms. Using rats as subjects, astronauts explored how learning occurs in space by measuring changes that take place in the central nervous system. Williams, who worked on electro-physiology research during the mid-1970's, said studying neurons in space was "a feat that can be hard to appreciate. We weren't sure it was going to work." He later added that "there are things going on in the nervous system we don't understand. The ability of the nervous system to adapt is impressive."
Losing Sleep and Balance
Payload specialist Jim A. Pawelczyk recounted his sleep experiments. The space shuttle is definitely not a good place to get a good night's sleep, he reported. Even though sleep quarters are very effective light blockers -- especially of the constant sunrises encountered in orbit -- and sound attenuators dampen noise, sleep comes hard. Astronauts become shift workers to handle their myriad tasks. Crewmembers reported an average sleep of 5 to 6 hours, compared to the typical period of 7 to 8 hours on Earth. "You virtually sleep at your desk; you live at work for 2½ weeks," said Pawelczyk. "You are constantly thinking about how you can do this or that task better, and you take that along with you to bed." Sleep difficulty has produced a number of studies that have begun to shed light on sleep disorders on Earth as well as in space.
Neurolab STS-90 studied changes in the balance system of humans in space, specifically the effects on the vestibular system -- the balance organs in the ear and all the connections they make to the eyes, brain and muscles. After adapting to space, the astronauts had to readapt when returning to Earth. Upon reentering the atmosphere, a full-pressure suit worn with a helmet helped the astronauts withstand the pull of newly felt gravity. Astronauts became aware of the effects of substantial muscle atrophy and imbalance. "I felt like I was shrinking under the weight of the suit," said Hire. "After landing and climbing out of the shuttle, we were clumping around, struggling against gravity. Even though we exercised on board, it is hard to keep up with muscle loss. It was a wobbly walk at the beginning. When leaning forward, you felt as if you were going to continue into a somersault. If I were to play tennis, I would probably fall on my nose."
Linnehan emphasized the importance of the Neurolab mission in overcoming the effects of bone atrophy in order to make further space flight possible. "If we don't figure out how to stem nerve-muscle degeneration, we are not going to be able to travel to other planets or live in space stations. We would face the risk of fractures when returning to Earth," he said.
Looking on the bright side, Astronaut Jay C. Buckey, Jr., payload specialist and professor of medicine at Dartmouth Medical School, joked that at least in space "you can put your pants on both legs at the same time."
After the space shuttle is brought to a smooth landing, the mission has yet to conclude. Astronauts are subjected to a variety of tests for 10 hours. In subsequent days, they report to NASA laboratories to continue data collection.
The NASA team presented NIDCD director Dr. James Battey with a gift commemorating NIH's part in mission STS-90 -- a plaque bearing the image of the space shuttle Columbia coming out of a neuron, accompanied by scenes of the flight. The mission was supported by NHLBI, NIA, NIDCD, NINDS and the Center for Scientific Review.
Hire reflected the opinion of the crew when she said, "We are not celebrities. It's a fantastic personal experience being part of this crew and of a science with far-reaching implications." That didn't change the impressions of an adoring NIH audience.
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