Sclera other species share, but also to the fact that the human iris is relatively small and comprises a significantly smaller portion of the exposed eye surface compared to other animals. It is theorized that this adaptation evolved because of our social nature as the eye became a useful communication tool in addition to a sensory organ. It is believed that the conspicuous sclera of the human eye makes it easier for one individual to infer where another individual is looking, increasing the efficacy of this particular form of nonverbal communication. Animal researchers have also found that, in the course of
Development of the human cerebral cortex during neurogenesis at mouse E10.5 to E12.5. Of the six layers found within the cortex, "layer 1 is the most superficial layer of the cortex...composed of Cajal-Retzius neurons and pyramidal cortex cells." This layer is unique in the aspect that these cells migrate to the outer edge of the cortex opposed to the migration experienced by the other 5 layers. Layer one is also characterized by expression of reelin, transcription factor T-box brain 1, and cortical migratory neuronal marker. The second and third layers, or the External Granular layer and External Pyramidal layer respectively, are formed around mouse E13.5 to