Quantitative analysis of cell columns in the cerebral cortex

Buxhoeveden, Daniel P.; Switala, Andrew E.; Roy, Emil; Casanova, Manuel F.

doi:10.1016/s0165-0270(99)00192-2

Cited by 60 publications

(47 citation statements)

References 61 publications

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“…Similarly, cell arrays are derived from the ontogenetic minicolumn and are therefore one cell-wide (Casanova, Trippe et al 2007). Previous column detection routines used this assumption and took the separation between minicolumns as being of the same order of magnitude as the separation between cell soma (Buxhoeveden, Switala et al 2000). While this assumption may hold true for columns in laminas II and III, it does not hold for those laminas where granular or stellar neurons abound, i.e., lamina IV.…”

Section: Discussionmentioning

confidence: 99%

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Recursive trace line method for detecting myelinated bundles: A comparison study with pyramidal cell arrays

Konkachbaev

Switala

Elmaghraby

2008

Journal of Neuroscience Methods

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Minicolumns are thought to be the smallest cortical modules within the hierarchical organization of the isocortex. Several reports suggest alterations in minicolumnar morphometry may be involved in psychiatric disorders such as autism, dyslexia, and schizophrenia. Thus far anatomical studies of minicolumns have primarily relied on measurements of pyramidal cell arrays. This study expands on a recursive trace line segmentation method used to define morphometric measures for myelinated axon bundles. The results were compared against those of pyramidal cell arrays derived from immediately adjacent serial sections. Width estimates based on cell somas and myelinated axon bundles were highly correlated (r = 0.9888). Histograms of signal intensity using the recursive trace line method produced expected features of myeloarchitectonics; that is, bundles of Meynert and intervening interradiary plexus. The close correspondence of derived values for myelinated axon bundles and pyramidal cell arrays suggests their participation and interaction within the same modular arrangement of the isocortex.

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Section: Discussionmentioning

confidence: 99%

“…The spacing between myelinated fiber bundles provides an alternative to the scale estimate method employed in measuring distances between pyramidal cell arrays (Buxhoeveden, Switala et al 2000). While bundles of axons appear to vary in thickness as they traverse laminas, they do not bifurcate.…”

Section: Discussionmentioning

confidence: 99%

Recursive trace line method for detecting myelinated bundles: A comparison study with pyramidal cell arrays

Konkachbaev

Switala

Elmaghraby

2008

Journal of Neuroscience Methods

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“…It is intriguing to consider that the arrival of serotonergic afferents in the cortex may alter reelin levels early enough to have a major impact on the formation of functional cortical columns, because: (1) the formation of cortical columns continues into early postnatal life and is controlled by transient cortical networks dependent on CR cells (Luhmann et al, 2003) and reelin secretion (Nishikawa et al, 2002); and (2) the development of cortical columns depends on GABAergic interneurons (Buxhoeveden et al, 2000b;Casanova et al, 2002c) that establish their connections with projection neurons at the late stages of corticogenesis and that may be at least partially guided by CR cells (Shinozaki et al, 2002;Ang et al, 2003). The columnar organization may be particularly vulnerable in the large and convoluted primate forebrain, where it is much more prominent during migratory phases of cortical development (Sidman and Rakic, 1973;Rakic, 1988Rakic, , 2003.…”

Section: Discussionmentioning

confidence: 99%

Early Serotonergic Projections to Cajal-Retzius Cells: Relevance for Cortical Development

Janušonis¹,

Glunčić²,

Rakić³

2004

J. Neurosci.

135

123

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Although the serotonergic system plays an important role in various neurological disorders, the role of early serotonergic projections to the developing cerebral cortex is not well understood. Because serotonergic fibers enter the marginal zone (MZ) before birth, it has been suggested that they may influence cortical development through synaptic contacts with Cajal-Retzius (CR) cells. We used immunohistochemistry combined with confocal and electron microscopy to show that the earliest serotonergic projections to the MZ form synaptic contacts with the somata and proximal dendrites of CR cells as early as embryonic day 17. To elucidate the functional significance of these early serotonergic contacts with CR cells, we perturbed their normal development by injecting pregnant mice with 5-methoxytryptamine. Lower reelin levels were detected in the brains of newborn pups from the exposed animals. Because reelin plays an important role in the cortical laminar and columnar organization during development, we killed some pups from the same litters on postnatal day 7 and analyzed their presubicular cortex. We found that the supragranular layers of the presubicular cortex (which normally display a visible columnar deployment of neurons) were altered in the treated animals. Our results suggest a mechanism of how serotonergic abnormalities during cortical development may disturb the normal cortical organization; and, therefore, may be relevant for understanding neurological disorders in which abnormalities of the serotonergic system are accompanied by cortical pathology (such as autism).

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“…** Their method requires that sections be oriented so that visually observed microcolumns align vertically. Then, a Gaussian density distribution is calculated along the horizontal axis, and maxima are assumed to be the centers of microcolumns, although any that appear to be truncated are discarded (31). From visually confirmed individual microcolumns, many measures that are similar to ours are collected (e.g., W and P), but other quantities (e.g., cell spacing and the total path͞length ratio) cannot be derived from our density map.…”

Section: Discussionmentioning

confidence: 99%

Age-related reduction in microcolumnar structure in area 46 of the rhesus monkey correlates with behavioral decline

Cruz

Roe

Urbanc

et al. 2004

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

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Many age-related declines in cognitive function are attributed to the prefrontal cortex, area 46 being especially critical. Yet in normal aging, studies indicate that neurons are not lost in area 46, suggesting that impairments result from more subtle processes. One cortical feature that is functionally important, but that has not been examined in normal aging because of a lack of efficient quantitative methods, is the vertical arrangement of neurons into microcolumns, a fundamental computational unit of the cortex. By using a density-map method derived from condensed-matter physics, we quantified microcolumns in area 46 of seven young and seven aged rhesus monkeys that had been cognitively tested. This analysis demonstrated that there is no age-related reduction in total neuronal density or in microcolumn width, length, or periodicity. There was, however, a statistically significant decrease in the strength of microcolumns, indicating microcolumnar disorganization. This reduction in strength was significantly correlated with age-related cognitive decline on tests of spatial working memory and recognition memory independent of the effect of age. Modeling demonstrated that random neuron displacements of Ϸ30% of a neuronal diameter (<3 m) produced the observed reduction in strength. Hence, it is possible that, with changes in dendrites and myelinated axons, subtle displacements of neurons occur that alter microcolumnar structure and correlate with ageinduced dysfunction. Therefore, quantitative measurement of microcolumnar structure may provide a sensitive morphological method to assay microcolumnar function in aging and other conditions. minicolumns ͉ density map ͉ cerebral cortex ͉ primate brain ͉ modeling

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Quantitative analysis of cell columns in the cerebral cortex

Cited by 60 publications

References 61 publications

Recursive trace line method for detecting myelinated bundles: A comparison study with pyramidal cell arrays

Recursive trace line method for detecting myelinated bundles: A comparison study with pyramidal cell arrays

Early Serotonergic Projections to Cajal-Retzius Cells: Relevance for Cortical Development

Age-related reduction in microcolumnar structure in area 46 of the rhesus monkey correlates with behavioral decline

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