ABSTRACT
Normal has been defined as a rule or reference standard, and abnormal as deviation or aberration from it. For a population of humans or rats or some other species, normal is the attributes of form and behavior of the members of the population who have been able to reproduce the species in the course of evolution. The motor-sensory cortex, which occupies much of the frontal half of the isocortex in rats, and the corticospinal tract system, one of its major outflows, are concepts based on an accumulation of anatomic, physiologic, and behavioral studies. That radiation impaired the ability of animals to track and jump to the moving platform could be supported by considering performances of normals and 200-r rats as one group and 300-, 400-, and 600-r rats as another. Rats whose eyeballs were surgically removed under ether anesthesia at birth were trained to jump from one platform to another.
