Gyrification

Gyrification is the process of forming the characteristic folds of the cerebral cortex. The peak of such a fold is called a gyrus (plural: gyri), and its trough is called a sulcus (plural: sulci). In most mammals, gyrification usually begins during embryogenesis and fetal development when neurogenesis builds the neuronal cortical layers. Primates, cetaceans, and ungulates have extensive cortical gyri, with a few species exceptions. Gyrification in these animals continues well into postnatal life. The buildup of folds in the brain results in a larger cortical surface area. This is known to increase the speed of brain cell communication, because cortical folds allow for cells in the same pathways to be closer to each other, which in turn requires less energy to send those signals shorter distances. There is also evidence to suggest a positive relationship between brain gyrification and cognitive function processes such as faster reaction times and information processing speed, and better verbal working memory.