ABSTRACT
The peripheral nervous system serves to relay neural signals to and from the brain and spinal cord in the central nervous system. The input of information to the central nervous system comes from a variety of neurons linked to sensory receptors throughout the body. The eye is a transducer that has been highly conserved throughout vertebrate evolution, whose function is to convert the energy of light into nervous impulses. The retina converts the light into nervous impulses, but unlike a camera, the retina does far more in terms of signal processing and interpretation. The authors show that the central and peripheral nervous systems, including the sensory organs that input information from the environment, have a varied dependence on resident stem cells. The role of these stem cells ranges from the generation of new neurons that serve to increase the learning capacity of the brain, for example, expanding the profile of olfactory neurons in rodents.
