sulcus

https://doi.org/10.1351/goldbook.11266
Any long, narrow groove, furrow or shallow depression, specifically referring to one of the fissures on the surface of the brain.
Source:
PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 809 [Terms] [Paper]