Architectonic Subdivisions of Neocortex in the Galago (<i>Otolemur garnetti</i>)

Wong, Peiyan; Kaas, Jon H.

doi:10.1002/ar.21109

Cited by 62 publications

(106 citation statements)

References 229 publications

(532 reference statements)

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“…This suggestion is consistent with the less pronounced cytoarchitectonic differences across cortical areas in prosimian primates (21), which also have less neocortex in proportion to the rest of the brain compared with other primates (22). We suggest that high neuron density represents a cortical specialization that emerged more strongly in some lines of primate evolution.…”

Section: Discussionsupporting

confidence: 81%

Neuron densities vary across and within cortical areas in primates

Collins

Airey²,

Young

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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355

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The numbers and proportion of neurons in areas and regions of cortex were determined for a single cortical hemisphere from two prosimian galagos, one New World owl monkey, one Old World macaque monkey, and one baboon. The results suggest that there is a common plan of cortical organization across the species examined here and also differences that suggest greater specializations in the Old World monkeys. In all primates examined, primary visual cortex (V1) was the most neuron-dense cortical area and the secondary visual areas had higher-than-average densities. Primary auditory and somatosensory areas tended to have high densities in the Old World macaque and baboon. Neuronal density varies less across cortical areas in prosimian galagos than in the Old World monkeys. Thus, cortical architecture varies greatly within and across primate species, but cell density is greater in cortex devoted to the early stages of sensory processing.cell density | cortex | isotropic fractionator | neuron number T he basic building blocks of information-processing circuits, the neurons and nonneuron cells of the cerebral cortex, have never been quantified in relation to identified cortical areas and regions across the entire cortical sheet. Several studies have reported total numbers of cells and neurons for the entire cortex (1-4). These reports are useful for examining cortical scaling principles across species, but because the cerebral cortex is such a heterogeneous structure with multiple parallel sensory and motor processing systems, whole-cortex cell number data have limited utility for understanding cortical information-processing circuits. Studies that have analyzed the cellular composition of particular cortical areas generally focused on a single cortical area or examined a limited number of areas. These studies (e.g., ref. 5) provide valuable comparative data, and a recent review thoughtfully considers differences between species (6). However, a global examination of the cellular composition of the cortical expanse with attention to cortical areas is clearly lacking in the published literature. A cellular and neuronal density map of the cortex of a number of species of primates and other mammals would contribute to interpretations of neuroimaging data in clinical and in cognitive neuroscience experimental settings. The density map also would improve our knowledge of processing circuits in the cortex and provide a foundation on which to build a cortical connection map (7) and on which to base neural network models of cortical function. The data presented here begin to fill this gap in our knowledge of cellular distribution patterns in the cortex.Although it seems obvious that areas and regions of the cortex vary in neuronal densities according to information-processing demands, there currently is little data on cell numbers and distribution across the cortex within and across species. Small data sets examining a few cortical areas often have generated erroneous conclusions. For example, results from one study are pervasive...

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Section: Discussionsupporting

confidence: 81%

Neuron densities vary across and within cortical areas in primates

Collins

Airey²,

Young

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

355

358

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“…In prosimians and tree shrews, VGLUT2 IR does identify patchy blob-like structures in layer 3B of V1 that correspond to CO-dense blobs or patches in the same layer (Wong and Kaas, 2009b, 2010). However, in New World and Old World monkeys, as well as humans, VGLUT2 IR only reveals sparse distributions of geniculate terminals in layer 3B that may be periodic and coincident with the CO blobs (Bryant et al, 2012; Garcia-Marin et al, 2012; Balaram et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Towards a unified scheme of cortical lamination for primary visual cortex across primates: insights from NeuN and VGLUT2 immunoreactivity

Balaram

Kaas

2014

Front. Neuroanat.

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Primary visual cortex (V1) is clearly distinguishable from other cortical areas by its distinctive pattern of neocortical lamination across mammalian species. In some mammals, primates in particular, the layers of V1 are further divided into a number of sublayers based on their anatomical and functional characteristics. While these sublayers are easily recognizable across a range of primates, the exact number of divisions in each layer and their relative position within the depth of V1 has been inconsistently reported, largely due to conflicting schemes of nomenclature for the V1 layers. This conflict centers on the definition of layer 4 in primate V1, and the subdivisions of layer 4 that can be consistently identified across primate species. Brodmann’s (1909) laminar scheme for V1 delineates three subdivisions of layer 4 in primates, based on cellular morphology and geniculate inputs in anthropoid monkeys. In contrast, Hässler’s (1967) laminar scheme delineates a single layer 4 and multiple subdivisions of layer 3, based on comparisons of V1 lamination across the primate lineage. In order to clarify laminar divisions in primate visual cortex, we performed NeuN and VGLUT2 immunohistochemistry in V1 of chimpanzees, Old World macaque monkeys, New World squirrel, owl, and marmoset monkeys, prosimian galagos and mouse lemurs, and non-primate, but highly visual, tree shrews. By comparing the laminar divisions identified by each method across species, we find that Hässler’s (1967) laminar scheme for V1 provides a more consistent representation of neocortical layers across all primates, including humans, and facilitates comparisons of V1 lamination with non-primate species. These findings, along with many others, support the consistent use of Hässler’s laminar scheme in V1 research.

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“…Brain sections were stained for cytochrome oxidase (CO), Nissl, and vesicle glutamate transporter 2 (VGluT2). Standard tissue staining protocols were followed, with details described in [49; 75; 98]. VGluT2 immunostain reveals thalamocortical terminations in layer 4.…”

Section: Methodsmentioning

confidence: 99%

Differential fMRI activation to noxious heat and tactile stimuli in parasylvian areas of new world monkeys

Chen

Dillenburger

Wang

et al. 2012

Pain

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Emerging evidence supports an important role of posterior parasylvian areas in both pain and touch processing. Whether there are separate or shared networks for these sensations remains controversial. The present study compared spatial patterns of brain activation in response to unilateral nociceptive heat (47.5° C) or innocuous tactile stimulation (8 Hz vibration) to digits through high-resolution fMRI in squirrel monkeys. In addition, the temporal profile of heat stimulus evoked fMRI BOLD signal changes was characterized. By examining high-resolution fMRI and histological measures at both the individual and group levels, we found that both nociceptive heat and tactile stimuli elicited activation in bilateral secondary somatosensory and ventral parietal areas (S2/PV) and in ipsilateral ventral somatosensory area (VS) and retroinsula (Ri). Bilateral posterior insular cortex (pIns) and area 7b responded preferentially to nociceptive heat stimulation. Single voxels within each activation cluster showed robust BOLD signal changes during each block of nociceptive stimulation. Across animals (n = 11), nociceptive response magnitudes of contralateral VS and pIns, and ipsilateral Ri were significantly greater than corresponding areas in the opposite hemisphere. In sum, both distinct and shared areas in regions surrounding the posterior sylvian fissure were activated in response to nociceptive and tactile inputs in non-human primates.

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Architectonic Subdivisions of Neocortex in the Galago (Otolemur garnetti)

Cited by 62 publications

References 229 publications

Neuron densities vary across and within cortical areas in primates

Neuron densities vary across and within cortical areas in primates

Towards a unified scheme of cortical lamination for primary visual cortex across primates: insights from NeuN and VGLUT2 immunoreactivity

Differential fMRI activation to noxious heat and tactile stimuli in parasylvian areas of new world monkeys

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