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
Satellite glial cell tumor necrosis factor α (TNFα) are other cellular factors that work to sensitize neurons to pain. SGCs are present in the PNS in fewer numbers than other more well-known types of glial cells, like astrocytes, but have been determined to affect nociception because of some of their physiological and pharmacological properties. In fact, just like astrocytes, SGCs have the ability to sense and regulate neighboring neuronal activity. First, after a period of nerve cell injury, SGCs are known to up-regulate GFAP and to undergo cell division. They have the ability to release chemoattractants, which are analogous to those released by