sulcus: Information and Much More from Answers.com
Gray's Fig. 726– Lateral surface of left cerebral hemisphere, viewed from the side.
Gray's Fig. 727 - Medial surface of left cerebral hemisphere.
In neuroanatomy, a sulcus (Latin: "furrow", pl. sulci) is a depression or fissure in the surface of the brain. It surrounds the gyri, creating the characteristic appearance of the brain in humans and other large mammals.
Large furrows (sulci) that divide the brain into lobes are often called fissures. The large furrow that divide the two hemispheres - the interhemispheric fissure - is very rarely called a "sulcus".
Individual variation
The sulcal pattern varies between human individuals, and the most elaborate overview on this variation is probably an atlas by Ono, Kubick and Abernathey: Atlas of the Cerebral Sulci[1]. Some of the larger sulci are, however, seen across individuals - and even species - so it is possible to establish a nomenclature.
Gyrification across species
The variation in the amount of fissures in the brain ("gyrification") between species is more related to the overall size of the animal rather than the encephalization. That is, large animals have many sulci:
- "[L]arge rodents such as beavers (40 pounds) and capybaras (150 pounds) have many more sulci than smaller rodents such as rats and mice - but also more fissures than smaller monkeys"[2].
Notable sulci
- Lateral sulcus
- Central sulcus
- Postcentral sulcus
- Precentral sulcus
- Cingulate sulcus
- Superior frontal sulcus
- Inferior frontal sulcus
Macaque
A macaque has a more simple sulcal pattern. In a monograph Bonin and Bailey list the following as the primary sulci[3]:
- Calcarine fissure (ca)
- Central sulcus (ce)
- Sulcus cinguli (ci)
- Hippocampal fissure (h)
- Sulcus intraparitalis (ip)
- Lateral fissure (or Sylvian fissure) (la)
- Sulcus olfactorius (olf)
- Medial parieto-occipital fissure (pom)
- fissura rhinalis (rh)
- Sulcus temporalis superior (ts) - this sulcus runs parallel to the lateral fissure and extends to the temporal pole and often superficially merges with it.
See also
References
- ^ Ono, Kubick, Abernathey, Atlas of the Cerebral Sulci, Thieme Medical Publishers, 1990. ISBN 0-86577-362-9. ISBN 3-13-732101-8.
- ^ Martin I. Sereno, Roger B. H. Tootell, "From Monkeys to humans: what do we now know about brain homologies," Current Opinion in Neurobiology 15:135-144, (2005).
- ^ Gerhardt von Bonin, Percival Bailey, The Neocortex of Macaca Mulatta, The University of Illinois Press, Urbana, Illinois, 1947
External links
| Brain: telencephalon (cerebrum, cerebral cortex, cerebral hemispheres) | |
|---|---|
| Primary sulci/fissures | Medial longitudinal, Lateral, Central, Parietoöccipital, Calcarine, Cingulate, Callosal Collateral fissure |
| Frontal lobe | Precentral gyrus (Primary motor cortex, 4), Precentral sulcus, Superior frontal gyrus/Frontal eye fields (6, 8, 9), Middle frontal gyrus (46), Inferior frontal gyrus (44-Pars opercularis, 45-Pars triangularis), Orbitofrontal cortex (10, 11, 12, 47) |
| Parietal lobe | Somatosensory cortex (Primary (1, 2, 3, 43), Secondary (5)), Precuneus (7m), Parietal lobules (Superior (7l), Inferior (40)), Angular gyrus (39), Intraparietal sulcus, Marginal sulcus |
| Occipital lobe | Primary visual cortex (17), Cuneus, Lingual gyrus, 18, 19 - Lateral occipital sulcus |
| Temporal lobe | Primary auditory cortex (41, 42), Superior temporal gyrus (38, 22), Middle temporal gyrus (21), Inferior temporal gyrus (20), Fusiform gyrus (37) Medial temporal lobe (Amygdala, Hippocampus, Parahippocampal gyrus (27, 28, 34, 35, 36) |
| Cingulate cortex/gyrus | Subgenual area (25), anterior cingulate (24, 32, 33), Posterior cingulate (23, 31), Retrosplenial cortex (26, 29, 30), Supracallosal gyrus |
| white matter tracts | Corpus callosum (Splenium, Genu, Rostrum, Tapetum), Septum pellucidum, Ependyma, Internal capsule, Corona radiata, External capsule, Olfactory tract, Fornix (Commissure of fornix), Anterior commissure, Posterior commissure Terminal stria |
| Basal ganglia | Striatum (Putamen,Caudate nucleus, Nucleus accumbens), Globus pallidus, Claustrum, Subthalamic nucleus, Substantia nigra |
| Other | Insular cortex Olfactory bulb, Anterior olfactory nucleus Septal nuclei Basal optic nucleus of Meynert |
| Some categorizations are approximations, and some Brodmann areas span gyri. |
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