Which part of the human body is related with ''gyri'' and ''sulci''?

Neuroanatomy is the study of the structure and organization of the nervous system. Cerebral cortex is the largest region and plays a key role in memory, attention, perception, cognition, awareness, thought, language and consciousness. In neuroanatomy 'gyri' (pl. of gyrus) are ridges on the cerebral cortex and are generally surrounded by 'sulci' (pl. of sulcus). Sulci are the depressions or furrows. 'Gyri' and 'sulci' create the folded appearance of the human brain. As development continues, 'gyri' and 'sulci' begin to take shape on the fetal brain, with deepening indentations and ridges developing on the surface of the cortex. Changes in the structure of 'gyri' in the cerebral cortex are associated with various diseases and disorders. Gyrification is the process of forming the characteristic folds of cerebral cortex.