A laminar analysis of the number of neurons, glia, and synapses in the visual cortex (area 17) of adult macaque monkeys

O’Kusky, John R.; Colonnier, Marc

doi:10.1002/cne.902100307

Cited by 305 publications

(180 citation statements)

References 50 publications

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“…Both element density (i.e., sum of neurons, synapses, and glia) and number of incoming connections of the blobs is not as large as that of layer IVc (O'Kusky and Colonnier, 1982;Carroll and Wong-Riley, 1984), although spontaneous activity of blob neurons seems to be comparable with layer IVc (Livingstone and Hubel, 1984). The latter might be related to the lack of orientation selectivity in most blob neurons, which would make them more active in most natural viewing conditions (Livingstone and Hubel, 1984).…”

Section: Discussionmentioning

confidence: 94%

Vascularization of Cytochrome Oxidase-Rich Blobs in the Primary Visual Cortex of Squirrel and Macaque Monkeys

Keller¹,

Schüz²,

Logothetis³

et al. 2011

J. Neurosci.

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The close correlation between energy supply by blood vessels and energy consumption by cellular processes in the brain is the basis of blood flow-related functional imaging techniques. Regional differences in vascular density can be detected using high-resolution functional magnetic resonance imaging. Therefore, inhomogeneities in vascularization might help to identify anatomically distinct areas noninvasively in vivo. It was reported previously that cytochrome oxidase-rich blobs in the striate cortex of squirrel monkeys are characterized by a notably higher vascular density (42% higher than interblob regions). However, blobs have so far never been identified in vivo on the basis of their vascular density. Here, we analyzed blobs of the primary visual cortex of squirrel monkeys and macaques with respect to the relationship between vascularization and cytochrome oxidase activity. By double staining with cytochrome oxidase enzyme histochemistry to define the blobs and collagen type IV immunohistochemistry to quantify the blood vessels, a close correlation between oxidative metabolism and vascularization was confirmed and quantified in detail. The vascular length density in cytochrome oxidase blobs was on average 4.5% higher than in the interblob regions, a difference almost one order of magnitude smaller than previously reported. Thus, the vascular density that is closely associated with local average metabolic activity is a structural equivalent of cerebral metabolism and blood flow. However, the quantitative differences in vascularization between blob and interblob regions are small and below the detectability threshold of the noninvasive hemodynamic imaging methods of today.

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Section: Discussionmentioning

confidence: 94%

Vascularization of Cytochrome Oxidase-Rich Blobs in the Primary Visual Cortex of Squirrel and Macaque Monkeys

Keller¹,

Schüz²,

Logothetis³

et al. 2011

J. Neurosci.

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“…Other non-neuronal cells such as pericytes and endothelial vascular cells were carefully excluded (Ling and Leblond, 1973;Curcio and Coleman, 1982;O'Kusky and Colonnier, 1982;Sturrock, 1983;Peters et al, 1991).…”

Section: Methodsmentioning

confidence: 99%

Light microscopic quantification of morphological changes during aging in neurons and glia of the rat parietal cortex

et al. 1997

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Background: Different changes in neuronal and glial population of the aging brain have been described; however, the degree and extent of these changes are controversial. This study evaluates the quantitative and cytomorphometric effects of aging on neuronal and glial populations in the parietal cortex of the rat.Methods: The study was performed in two groups of rats aged 4-6 and 30-32 months. Cortical volume, neuronal density, glial density, and neuronal area, and shapes of the soma and nucleus were analyzed in cortical layers I, II-IV, V, and VI using serial sections stained with cresyl-fastviolet, and quantitative morphometric techniques.Results: No changes with age were found in volume of the cortex or neuronal density. Glial density increased significantly (mean for all layers 17%) in older rats. Layers II-IV, V, and VI showed an age-related decrease in the area of the neuronal soma. Neuronal shape, as revealed by the major/minor diameter ratio, also showed a decrease in old rats but only in layer II-IV. Nuclear area decreased with age only in layer VI.Conclusions: The stability of neuronal density together with the increased number of glial cells and the changes in neuronal soma size suggest that aged-related cognitive impairment could be a consequence of neuronal dysfunction rather than actual neuronal losses.

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“…A comparison with histology would have uncertainties due to its destructive nature. Contradictory reports suggest that histology has no affect (Schuz and Palm, 1989) and linearly decreases axon diameters (O'Kusky and Colonnier, 1982). However, tissue shrinkage is not expected for freshly excised or perfusion fixed tissues (Schuz and Palm, 1989).…”

Section: Limitations and Further Applications Of Qsimentioning

confidence: 97%

Indirect measurement of regional axon diameter in excised mouse spinal cord with q-space imaging: Simulation and experimental studies

et al. 2008

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Q-space imaging (QSI), a diffusion MRI technique, can provide quantitative tissue architecture information at cellular dimensions not amenable by conventional diffusion MRI. By exploiting regularities in molecular diffusion barriers, QSI can estimate the average barrier spacing such as the mean axon diameter in white matter (WM). In this work, we performed ex vivo QSI on cervical spinal cord sections from healthy C57BL/6 mice at 400MHz using a custom-designed uniaxial 50T/m gradient probe delivering a 0.6 µm displacement resolution capable of measuring axon diameters on the scale of 1 µm. After generating QSI-derived axon diameter maps, diameters were calculated using histology from seven WM tracts (dorsal corticospinal, gracilis, cuneatus, rubrospinal, spinothalamic, reticulospinal, and vestibulospinal tracts) each with different axon diameters. We found QSI-derived diameters from regions drawn in the seven WM tracts (1.1 to 2.1 µm) to be highly correlated (r 2 = 0.95) with those calculated from histology (0.8 to 1.8 µm). The QSI-derived values overestimated those obtained by histology by approximately 20%, which is likely due to the presence of extracellular signal. Finally, simulations on images of synthetic circular axons and axons from histology suggest that QSI-derived diameters are informative despite diameter and axon shape variation and the presence of intra-cellular and extra-cellular signal. QSI may be able to quantify nondestructively changes in WM axon architecture due to pathology or injury at the cellular level.

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A laminar analysis of the number of neurons, glia, and synapses in the visual cortex (area 17) of adult macaque monkeys

Cited by 305 publications

References 50 publications

Vascularization of Cytochrome Oxidase-Rich Blobs in the Primary Visual Cortex of Squirrel and Macaque Monkeys

Vascularization of Cytochrome Oxidase-Rich Blobs in the Primary Visual Cortex of Squirrel and Macaque Monkeys

Light microscopic quantification of morphological changes during aging in neurons and glia of the rat parietal cortex

Indirect measurement of regional axon diameter in excised mouse spinal cord with q-space imaging: Simulation and experimental studies

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