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In brain anatomy, the lunate sulcus or simian sulcus also known as the sulcus lunatus is a fissure in the occipital lobe[1] found in humans and more often larger when present in apes and monkeys.[2] The lunate sulcus marks the transition between V1 and V2.[3]

Lunate sulcus
Lateral surface of left cerebral hemisphere, viewed from the side.
LocationOccipital lobe
Latinsulcus lunatus
NeuroLex IDbirnlex_4017
Anatomical terms of neuroanatomy

The lunate sulcus lies further back in human brains but has a more frontal location in chimpanzees.[4] The evolutionary expansion of the frontal areas of the lunate sulcus would have caused a shift in the particular location of the fissure.[4][5] It has been hypothesized that evolutionary pressures resulted in the human brain undergoing internal reorganization to develop the capability of human language.[6] Furthermore, this reorganization must have been implemented during early maturity and is likely responsible for eidetic imagery in some adolescents.[6]

During early development, the neural connections in prefrontal cortex and posterior parietal lobe rapidly expand to allow capability for human language, while visual memory capacity of human brain would become limited.[7] Biological studies have demonstrated that the lunate sulcus is subject to white matter growth, and dental fossil and tomography studies have shown that the brain organization of Africanus is pongid-like.[8]


  1. ^ Allen JS, Bruss J, Damasio H (August 2006). "Looking for the lunate sulcus: a magnetic resonance imaging study in modern humans". Anat Rec A Discov Mol Cell Evol Biol. 288 (8): 867–76. doi:10.1002/ar.a.20362. PMID 16835937.
  2. ^ Srijit D, Shipra P (2008). "Unilateral absence of the lunate sulcus: an anatomical perspective". Rom J Morphol Embryol. 49 (2): 257–8. PMID 18516336.
  3. ^ Schmolesky, M. "The organization of the retina and visual system".
  4. ^ a b Rincon, P (2004). 3496549.stm "Human brain began evolving early" Check |url= value (help). bbc.
  5. ^ Bruner, E (2014). Human paleoneurology. Springer.
  6. ^ a b Ko, Kwang Hyun (2015). "Brain Reorganization Allowed for the Development of Human Language: Lunate Sulcus". International Journal of Biology. 7: 59. doi:10.5539/ijb.v7n3p59.
  7. ^ Gogtay, N (2004). "Dynamic mapping of human cortical development during childhood through early adulthood". Proceedings of the National Academy of Sciences. 101. doi:10.1073/pnass0402680101.
  8. ^ Dean, C (2001). "Growth processes in teeth distinguish modern humans from Homo erectus and earlier hominins". Nature. 414: 628–631. doi:10.1038/414628a. PMID 11740557.