Sulcus (neuroanatomy)

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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 (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".

[edit] 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.

[edit] 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].

[edit] Notable sulci

[edit] 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.

[edit] See also

Sulcus (anatomy)

[edit] Reference

↑ Ono, Kubick, Abernathey, Atlas of the Cerebral Sulci, Thieme Medical Publishers, 1990. ISBN 0865773629. ISBN 3137321018.
↑ 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

Telencephalon (cerebrum, cerebral cortex, cerebral hemispheres) - edit

primary sulci/fissures: medial longitudinal, lateral, central, parietoöccipital, calcarine, cingulate

frontal lobe: precentral gyrus (primary motor cortex, 4), precentral sulcus, superior frontal gyrus (6, 8), middle frontal gyrus (46), inferior frontal gyrus (Broca's area, 44-pars opercularis, 45-pars triangularis), prefrontal cortex (orbitofrontal cortex, 9, 10, 11, 12, 47)

parietal lobe: postcentral sulcus, postcentral gyrus (1, 2, 3, 43), superior parietal lobule (5), inferior parietal lobule (39-angular gyrus, 40), precuneus (7), intraparietal sulcus

occipital lobe: primary visual cortex (17), cuneus, lingual gyrus, 18, 19 (18 and 19 span whole lobe)

temporal lobe: transverse temporal gyrus (41-42-primary auditory cortex), superior temporal gyrus (38, 22-Wernicke's area), middle temporal gyrus (21), inferior temporal gyrus (20), fusiform gyrus (36, 37)

limbic lobe/fornicate gyrus: cingulate cortex/cingulate gyrus, anterior cingulate (24, 32, 33), posterior cingulate (23, 31),
isthmus (26, 29, 30), parahippocampal gyrus (piriform cortex, 25, 27, 35), entorhinal cortex (28, 34)

subcortical/insular cortex: rhinencephalon, olfactory bulb, corpus callosum, lateral ventricles, septum pellucidum, ependyma, internal capsule, corona radiata, external capsule

hippocampal formation: dentate gyrus, hippocampus, subiculum

basal ganglia: striatum (caudate nucleus, putamen), lentiform nucleus (putamen, globus pallidus), claustrum, extreme capsule, amygdala, nucleus accumbens

Some categorizations are approximations, and some Brodmann areas span gyri.

This page uses content from the English-language version of Wikipedia. The original article was at Sulcus (neuroanatomy). The list of authors can be seen in the page history. As with Psychology Wiki, the text of Wikipedia is available under the GNU Free Documentation License.

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