Mission Home Page Adult Neuronal Plasticity Team Physiology Overview Life evolved in Earth's gravitational field.
Animals learn tasks, such as walking, under the force of gravity.
When the gravity load is reduced, as it is in space, the nervous system is challenged. Because the body is weightless, nerves in the joints no longer sense the weight of a limb. When a person is floating, walking is not necessary, and maintaining balance is not important in space. The brain must relearn many tasks to compensate for this new environment. The fact that people can function well in space shows that the nervous system can compensate very effectively.