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Comparative organization of the claustrum: what does structure tell us about function?

Baizer JS, Sherwood CC, Noonan M, Hof PR - Front Syst Neurosci (2014)

Bottom Line: These theories postulate mechanisms like gap junctions between claustral cells or a "syncytium" to mediate intraclaustral processing.The presence of discontinuities in the structure of the claustrum, present but minimal in some primates, but dramatically clear in cetaceans, argues against the proposed mechanisms of intraclaustral processing of information.The best interpretation of function, then, is that each functional subdivision of the claustrum simply contributes to the function of its cortical partner.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Biophysics, University at Buffalo Buffalo, NY, USA.

ABSTRACT
The claustrum is a subcortical nucleus present in all placental mammals. Many anatomical studies have shown that its inputs are predominantly from the cerebral cortex and its outputs are back to the cortex. This connectivity thus suggests that the claustrum serves to amplify or facilitate information processing in the cerebral cortex. The size and the complexity of the cerebral cortex varies dramatically across species. Some species have lissencephalic brains, with few cortical areas, while others have a greatly expanded cortex and many cortical areas. This evolutionary diversity in the cerebral cortex raises several questions about the claustrum. Does its volume expand in coordination with the expansion of cortex and does it acquire new functions related to the new cortical functions? Here we survey the organization of the claustrum in animals with large brains, including great apes and cetaceans. Our data suggest that the claustrum is not always a continuous structure. In monkeys and gorillas there are a few isolated islands of cells near the main body of the nucleus. In cetaceans, however, there are many isolated cell islands. These data suggest constraints on the possible function of the claustrum. Some authors propose that the claustrum has a more global role in perception or consciousness that requires intraclaustral integration of information. These theories postulate mechanisms like gap junctions between claustral cells or a "syncytium" to mediate intraclaustral processing. The presence of discontinuities in the structure of the claustrum, present but minimal in some primates, but dramatically clear in cetaceans, argues against the proposed mechanisms of intraclaustral processing of information. The best interpretation of function, then, is that each functional subdivision of the claustrum simply contributes to the function of its cortical partner.

No MeSH data available.


Related in: MedlinePlus

(A, B) The claustrum in the human brain. The claustrum is shown on two coronal sections through the human brain about 17 mm apart. A is the more rostral. The arrows show the claustrum, which is quite small relative to the total size of the section. The images were downloaded from http://www.brains.rad.msu.edu and, http://brainmuseum.org sites supported by the US National Science Foundation, and used with permission. The brain had been embedded in celloidin and sectioned at 35 μm. Scale bar = 10 mm.
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Figure 6: (A, B) The claustrum in the human brain. The claustrum is shown on two coronal sections through the human brain about 17 mm apart. A is the more rostral. The arrows show the claustrum, which is quite small relative to the total size of the section. The images were downloaded from http://www.brains.rad.msu.edu and, http://brainmuseum.org sites supported by the US National Science Foundation, and used with permission. The brain had been embedded in celloidin and sectioned at 35 μm. Scale bar = 10 mm.

Mentions: Species differences in cortical organization are mirrored in differences in the size and shape of the claustrum. Buchanan and Johnson (2011) illustrate the shape and size of both cortex and claustrum in 26 different species. Kowiański et al. (1999) illustrated the shape of the claustrum in different species. They recognized five different morphological types; the shape of the dorsal claustrum in 8 different species is illustrated in Figure 5 (modified from Kowiański et al., 1999). It is important to note, however, that while all of these drawings show the claustrum as a continuous structure, examination of Nissl sections from the macaque monkey at higher magnification (as in Figure 3C) shows discontinuities. Figures 6A,B supplement the drawings of the human claustrum with photomicrographs of the human claustrum (at arrows) in Nissl-stained coronal sections of the human brain. The image in A shows a hint of a ventral enlargement as seen in macaque monkey; the image in B supports dorsal-ventral symmetry. A ventral enlargement is present in small-brain lissencephalic New World anthropoid primates such as owl monkeys, squirrel monkeys, titi monkeys, tamarins and marmosets, although it is not as pronounced in the strepsirrhine primates, the lemurs and lorises. However, while illustrations can show species variability in the form of the claustrum, they cannot relate the differences in the shape and size of the claustrum to differences in the numbers or organization or specializations of cortical areas.


Comparative organization of the claustrum: what does structure tell us about function?

Baizer JS, Sherwood CC, Noonan M, Hof PR - Front Syst Neurosci (2014)

(A, B) The claustrum in the human brain. The claustrum is shown on two coronal sections through the human brain about 17 mm apart. A is the more rostral. The arrows show the claustrum, which is quite small relative to the total size of the section. The images were downloaded from http://www.brains.rad.msu.edu and, http://brainmuseum.org sites supported by the US National Science Foundation, and used with permission. The brain had been embedded in celloidin and sectioned at 35 μm. Scale bar = 10 mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4079070&req=5

Figure 6: (A, B) The claustrum in the human brain. The claustrum is shown on two coronal sections through the human brain about 17 mm apart. A is the more rostral. The arrows show the claustrum, which is quite small relative to the total size of the section. The images were downloaded from http://www.brains.rad.msu.edu and, http://brainmuseum.org sites supported by the US National Science Foundation, and used with permission. The brain had been embedded in celloidin and sectioned at 35 μm. Scale bar = 10 mm.
Mentions: Species differences in cortical organization are mirrored in differences in the size and shape of the claustrum. Buchanan and Johnson (2011) illustrate the shape and size of both cortex and claustrum in 26 different species. Kowiański et al. (1999) illustrated the shape of the claustrum in different species. They recognized five different morphological types; the shape of the dorsal claustrum in 8 different species is illustrated in Figure 5 (modified from Kowiański et al., 1999). It is important to note, however, that while all of these drawings show the claustrum as a continuous structure, examination of Nissl sections from the macaque monkey at higher magnification (as in Figure 3C) shows discontinuities. Figures 6A,B supplement the drawings of the human claustrum with photomicrographs of the human claustrum (at arrows) in Nissl-stained coronal sections of the human brain. The image in A shows a hint of a ventral enlargement as seen in macaque monkey; the image in B supports dorsal-ventral symmetry. A ventral enlargement is present in small-brain lissencephalic New World anthropoid primates such as owl monkeys, squirrel monkeys, titi monkeys, tamarins and marmosets, although it is not as pronounced in the strepsirrhine primates, the lemurs and lorises. However, while illustrations can show species variability in the form of the claustrum, they cannot relate the differences in the shape and size of the claustrum to differences in the numbers or organization or specializations of cortical areas.

Bottom Line: These theories postulate mechanisms like gap junctions between claustral cells or a "syncytium" to mediate intraclaustral processing.The presence of discontinuities in the structure of the claustrum, present but minimal in some primates, but dramatically clear in cetaceans, argues against the proposed mechanisms of intraclaustral processing of information.The best interpretation of function, then, is that each functional subdivision of the claustrum simply contributes to the function of its cortical partner.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Biophysics, University at Buffalo Buffalo, NY, USA.

ABSTRACT
The claustrum is a subcortical nucleus present in all placental mammals. Many anatomical studies have shown that its inputs are predominantly from the cerebral cortex and its outputs are back to the cortex. This connectivity thus suggests that the claustrum serves to amplify or facilitate information processing in the cerebral cortex. The size and the complexity of the cerebral cortex varies dramatically across species. Some species have lissencephalic brains, with few cortical areas, while others have a greatly expanded cortex and many cortical areas. This evolutionary diversity in the cerebral cortex raises several questions about the claustrum. Does its volume expand in coordination with the expansion of cortex and does it acquire new functions related to the new cortical functions? Here we survey the organization of the claustrum in animals with large brains, including great apes and cetaceans. Our data suggest that the claustrum is not always a continuous structure. In monkeys and gorillas there are a few isolated islands of cells near the main body of the nucleus. In cetaceans, however, there are many isolated cell islands. These data suggest constraints on the possible function of the claustrum. Some authors propose that the claustrum has a more global role in perception or consciousness that requires intraclaustral integration of information. These theories postulate mechanisms like gap junctions between claustral cells or a "syncytium" to mediate intraclaustral processing. The presence of discontinuities in the structure of the claustrum, present but minimal in some primates, but dramatically clear in cetaceans, argues against the proposed mechanisms of intraclaustral processing of information. The best interpretation of function, then, is that each functional subdivision of the claustrum simply contributes to the function of its cortical partner.

No MeSH data available.


Related in: MedlinePlus