sulcation

noun

1. (countable, uncountable)A channel or furrow.
2. (countable, uncountable)Markings resembling channels or furrows, especially in shells, fossils, etc.

   “The ornamentation of the shell is a character of considerable palaeontological importance. . . . The types of ornamentation are two; longitudinal striation, and transverse sulcation conformable to the shape of the aperture.”

   “[T]he presence of sulcation in the brow horns of all the Arrhinoceratops specimens known at the present time suggests a certain constancy in this genus.”

3. (countable, uncountable)The development of or resulting formations of sulci in a brain cortex.

   “Lissencephaly refers to a diffusely smooth-surfaced cerebral hemisphere without sulcation.”

   “Since the appearance and development of sulci in the fetal brain follows a predictable pattern, the degree of sulcation may be used as an indicator of gestational age-related cortical development, both at autopsy and in vivo with fetal MRI.”

   “Gyration and sulcation occur during neuronal migration and continue until after birth.”