Radial glial cell and OPCs can be generated from radial glial cells "in vitro", more evidence is yet needed to conclude whether this process also occurs in the developing brain. Recently, radial glia that exclusively generate upper-layer cortical neurons have also been discovered. Since upper cortical layers have expanded greatly in recent evolution, and are associated with higher-level information processing and thinking, radial glia have been implicated as important mediators of brain evolution. The best characterized and first widely accepted function of radial glia is their role as scaffolds for neuronal migration in the cerebral and cerebellar cortexes. This role can be easily
Effect of spaceflight on the human body Effect of spaceflight on the human body Venturing into the environment of space can have negative effects on the human body. Significant adverse effects of long-term weightlessness include muscle atrophy and deterioration of the skeleton (spaceflight osteopenia). Other significant effects include a slowing of cardiovascular system functions, decreased production of red blood cells, balance disorders, eyesight disorders and a weakening of the immune system. Additional symptoms include fluid redistribution (causing the "moon-face" appearance typical in pictures of astronauts experiencing weightlessness), loss of body mass, nasal congestion, sleep disturbance, and excess flatulence. The engineering problems associated with leaving Earth and developing