A quantitative approach to cytoarchitectonics: software and hardware aspects of a system for the evaluation and analysis of structural inhomogeneities in nervous tissue

Cytoarchitectonic studies are based on the analysis of structural inhomogeneities in nervous tissue. Boundaries of brain regions are established where local structural properties such as numerical cell density, size, shape or orientation change. The measurement of these properties from histological sections with automatic devices is biased due to the thickness of the sections. In this study, the grey level index (GLI) is measured with a TV-based image analyzer from routine histological sections. This parameter is a biased estimate of the volume density of Nissl-positive structures. The histological section is digitized into GLI values by a computer-controlled scanning procedure. The result is stored in an image matrix which is processed by digital filtering in order to visualize the laminar pattern. GLI statistics of brain regions are evaluated from the pictorial data by delineating these regions with a cursor on a hard copy fixed to digitizer. Information from a series of sections is stored in a standardized data file and combined by specific application programs.

Ontogenesis of serotonin (5-HT) binding sites in the choroid plexus of the rat brain

The increase in density of 5-HT1c receptors in the choroid plexus of the third and lateral ventricles was analyzed in rats between the 1st and 90th postnatal days. An increase was found between the 3rd day and the 4th to 5th week, at which time adult values are attained. The development of the 5-HT1c receptors clearly differs from that of 5-HT1 receptors in other brain regions. The density in the choroid plexus is about 20% higher in the third ventricle than in the lateral ventricles.

The size of the zone of origin of callosal afferents projecting to the primary visual cortex contralateral to the remaining eye in rats monocularly enucleated at different postnatal ages

The cortical zone from which callosal afferents projecting to the primary visual cortex (area Oc1) originate was studied in monocularly enucleated and normal rats. The extent of this cortical strip was determined by retrograde labeling with HRP and by measurement of its width in coronal sections. Albino rats were monocularly enucleated from the 23rd ontogenetic day to the 120th and iontophoretical injections into Oc1 contralateral to the remaining eye were done more than one year after enucleation. The width of the labeled strip of perikarya in the hemisphere ipsilateral to the remaining eye was largest in neonatally enucleated rats (about 1.1 mm) and declined with increasing age at which enucleation was performed. Additionally, the perikarya of callosal afferents in the hemisphere ipsilateral to the remaining eye in rats enucleated as young adults (90th and 120th ontogenetic day) were labeled in significantly wider strips (about 0.6 mm) than in unoperated control rats (about 0.4 mm).

Ontogenesis of the laminar structure in areas 17 and 18 of the human visual cortex. A quantitative study

A quantitative morphological study of the pre- and postnatal development in the primary (area 17) and secondary (area 18) visual cortical regions was performed on 108 human brains. The neuropil proportion and thickness were measured with an image analyzer for the different cortical layers and the resulting data were approximated with logistic growth functions. The different layers show a marked heterochrony both within and between the areas. The neuropil proportion of layer I is the compartment to develop first in both areas. It has the lowest growth velocity, followed by layer VI and layers V, IV, III and II. This maturational sequence reflects the sequence of appearance of immature neurons during the migration period of neocortical ontogenesis. The development of the neuropil proportion is highly synchronized between areas 17 and 18 during the prenatal period, but in the first postnatal weeks, area 17 grows more quickly than area 18. Later on, this relation is reversed and area 18 reaches adult values of neuropil proportions about three months earlier than area 17. The growth in thickness of all layers is completed later than the growth in neuropil proportion. The growth in layer thickness is completed in Area 18 about two months earlier than in area 17, although area 18 has a greater cortical thickness. The results are compared with data on growth in volume, dendritic arborization and the development of visual function.

Autoradiographic identification and topographical analyses of high affinity serotonin receptor subtypes as a target for the novel putative anxiolytic TVX Q 7821

TVX Q 7821 is a putative non-benzodiazepine anxiolytic which has a high affinity to 5-HT1 receptors. In this study some of the binding characteristics of the radiolabeled drug using rat brain cryostat sections and the autoradiographic localization of binding sites using the LKB-Ultrofilm technique have been investigated. Parallel experiments have been performed using [3H]serotonin ( [3H]5-HT). Both [3H]TVX Q 7821 and [3H]5-HT bound specifically and in a saturable manner to tissue sections, the Kd values being 6.8 and 3.7 nmol/l, respectively. Quantitative autoradiography using computer-assisted image analysis revealed a mean inhibition by TVX Q 7821 of [3H]5-HT binding of 56% in many brain areas. The inhibition ranged from 80% in the hippocampus and entorhinal area to practically none in the substantia nigra and the dorsal subiculum. Color coded autoradiograms obtained either with [3H]5-HT or [3H]TVX Q 7821 showed a nearly identical pattern of labeling with high receptor densities in the hippocampus, the entorhinal area, the septum, the interpeduncular nucleus and the dorsal raphe. However, in some brain areas striking differences in the intensity of labeling were found. [3H]5-HT but not [3H]TVX Q 7821 bound strongly in the substantia nigra, the dorsal subiculum and the globus pallidus. It is proposed that TVX Q 7821 binds to a subtype of 5-HT1 receptor (the so-called 5-HT1A sites as recently proposed). Thus, the putative anxiolytic TVX Q 7821 may provide a means for the study of the functional role of 5-HT1 receptors.

Modification of callosal afferents of the primary visual cortex ipsilateral to the remaining eye in rats monocularly enucleated at different stages of ontogeny

Callosal afferents to the primary visual cortex (area Oc1) mainly originate in the border region between the lateral portion of the primary visual cortex (area Oc1) and the laterally positioned secondary visual cortex (area Oc2L) of the contralateral hemisphere. The extent of this region has been determined by retrograde labeling with horseradish peroxidase (HRP). In normal rats the width of the retrogradely labeled cortical strip is about 0.3 mm. In rats monocularly enucleated from the 23rd up to the 44th ontogenetic day and subsequently injected as adults with HRP into Oc1 ipsilateral to the remaining eye, the perikarya of the callosal afferents from the opposite hemisphere are labeled in the form of significantly wider columns (about 0.8 mm) than in animals enucleated from the 50th ontogenetic day onwards. The latter do not differ from controls.

The ontogenetic development of serotonin (5-HT1) receptors in various cortical regions of the rat brain

The distribution of serotonin (5-HT1) receptors in various cortical regions of the rat brain has been examined during ontogenesis by quantitative autoradiography. An increase in binding site density between the first postnatal day and adult age was observed and could be approximated by a sigmoid shaped (logistic) growth curve. A marked heterochrony in the increase of binding site density is found in the 13 analyzed cortical regions. Binding sites develop earlier in neocortex than in allocortical areas. Fifty percent of the binding site density of adult age is reached in the motor cortex at the 9th postnatal day, followed by the primary somatosensory cortex one day later, by the medial prefrontal cortex on the 12th day, by the fascia dentata on the 14th day and by the CA 1-region on the 20th day. A detailed analysis of the frontal, medial prefrontal and hippocampal regions also shows a heterochrony within these regions. Adult values of binding site densities are also reached at different ages in the various cortical regions. The highest receptor densities were observed in the dorsal subiculum, the lowest in the primary somatosensory cortex.

A quantitative approach to cytoarchitectonics. X. The areal pattern of the neostriatum in the domestic pigeon, Columba livia f.d. A cyto- and myeloarchitectonical study

The areal pattern of the neostriatum of the domestic pigeon, Columba livia f.d., is described in detail. The map was completed with the help of cyto- and myeloarchitectonical studies during which both qualitative and quantitative methods were applied. The map is divided into 16 areas which are characterized in this paper. Most of these areas can be interpreted as being not only structural but also functional units. The areas Ne 1, Ne 7, and Ne 12 represent primary projection fields. The areas Ne 2, Ne 4, Ne 5, Ne 9, Ne 13, and Ne 14 can be regarded as associative areas, closely connected with the primary areas. The areas Ne 6, Ne 11, Ne 15, and Ne 16 are described with regard to a possible integrative function.

Alterations of the retina in chick embryos induced by systemic alpha-bungarotoxin application

The application of alpha-bungarotoxin onto the chorio-allantoic membrane of chick embryos between the 11th and 18th day of incubation leads to alterations of retinal development. The most significant qualitative change is the appearance of retinal rosettes formed by receptor cells. These rosettes are infoldings of the receptor cell layer. Quantitatively, an enlargement in volume of the receptor and outer nuclear layer can be found together with a simultaneous decrease of the other retinal layers. The toxin seems to suspend the naturally occurring nerve cell death in the receptor cell population

The monocular and binocular subfields of the rat's primary visual cortex: a quantitative morphological approach

Primary visual cortex in the rat was studied by a variety of methods: transsynaptic transport of labelled amino acids, 2-deoxyglucose, and staining for perikarya, myelin, and acetylcholinesterase. The analysis was aided by a computer-controlled television image analyzer. The results obtained with different methods agree with one another in describing the position and extent of the entire primary visual cortex as well as its monocular (medial) and binocular (lateral) subareas.

A quantitative approach to cytoarchitectonics. IX. The areal pattern of the hyperstriatum ventrale in the domestic pigeon, Columba livia f.d

A map of the areal pattern of the hyperstriatum ventrale in the domestic pigeon (Columba livia f.d.) is proposed. This map is based mainly on the distribution of the grey level index which has been characterized using an automatic image analyzer. Twelve areas are described. They are classified into two groups (Hvm 1-6, Hvl 1-6) which are defined by a different range of grey level indices. Three of these areas show topographic relationships to primary projection areas in the neighbouring neostriatum (Nucleus basalis, Ectostriatum, Feld L), and connections are in part well known. Therefore, these areas are assumed to be associative in function. The function of the other areas remains an open question.

[Postmortem DNA and RNA synthesis. Preliminary studies in human cadavers]

Postmortem DNA and RNA synthesis was detected in tissue specimens harvested from two cadavers at different intervals between 2.5 and 32 h postmortem. Each tissue specimen was incubated for 1 h in a 3H-thymidine or 3H-cytidine solution. DNA- as well as RNA-synthesizing cells were found in skin tissue and bone marrow throughout the interval investigated. Cytidine incorporation decreased progressively during the course of the postmortem interval. DNA and RNA synthesis was also observed in cells of the testis, which were predominantly spermatogonia cells in the case of DNA. Low-grade RNA synthesis was detected in bowel epithelial cells up to 2.5 h postmortem; DNA synthesis was not present during the interval investigated. No supravital phenomena were observable in the splenic tissues examined.

Ipsilateral projections to the terminal nuclei of the accessory optic system in the albino rat

The projection of the retinal ganglion cells to the terminal nuclei of the accessory optic system has been re-examined in the albino rat. After intravitreal injection of [3H]leucine the contralateral and ipsilateral terminal nuclei were labeled. This complete ipsilateral projection in the rat has, of yet, not been documented.

A quantitative approach to cytoarchitectonics. VIII. The areal pattern of the cortex of the albino mouse

The cerebral cortex of the albino mouse was examined by means of a quantitative method. An image analyzer was used in conjunction with an automatic scanning procedure to determine the grey level index in Nissl-stained sections. Computer plots of various ranges of grey level indices enabled delineation of cortical areas, from which cortical maps were graphically reconstructed. The cortical areal pattern is, in some regions, similar to the commonly used map of Caviness (1975) but differs considerably in other regions, especially in the temporal one. Furthermore, the primary visual cortex of the mouse was shown to be composed of two distinct cytoarchitectonic areas. The results of the study are discussed with respect to the literature on anatomical and functional localizations in the mouse cerebral cortex.

The development of the eye in Astyanax mexicanus (Characidae, Pisces), its blind cave derivative, Anoptichthys jordani (Characidae, Pisces), and their crossbreds. A scanning- and transmission-electron microscopic study

The development of the eye of the characin Astyanax mexicanus, of its blind derivative Anoptichthys jordani, and crossbreds of both forms was studied at different ontogenetic stages by means of scanning- and transmission-electron microscopy. Astyanax exhibits a form of eye development resembling that in other characid species. A severe reduction of the eye could be observed in Anoptichthys starting with the second day of ontogeny. This degenerational process is characterized by the following features: 1) An overgrowth of epidermal tissue that gradually covers the surface of the eyeball; 2) the sinking of the eyeball below the surface of the integument; 3) the formation of epidermal channels from the body surface to the disappearing surface of the eyeball; 4) a severe degeneration of the retinal sensory cells; and 5) a small number of pigment granules in the pigment epithelial cells. The progeny of crosses between Astyanax and Anoptichthys show varying degrees of these degenerational signs. Taste buds and the lateral line organ display identical features in all crosses analyzed with the scanning electron microscope.

How many sections must be measured in order to reconstruct the volume of a structure using serial sections?

When reconstructing the volumes of organs, or other individual bodies, the areas of these structures are usually determined with the help of serial sections and the volume thus estimated. The actual number of serial sections that have to be taken into account, whilst arranging such a study, is of great importance. This present paper shows that about 20 equidistant sections are sufficient in order to determinate the volume, even that of extremely irregular formed bodies, whereby the error will not exceed 5%.

Estimation of volume fractions in nervous tissue with an image analyzer

The calculation of volume fractions in nervous tissue is a method often used in neuroanatomy. In ontogenetic studies and problems concerning aging, as well as after experimental procedures, volume fractions are calculated in order to quantify the results. Grey level index (GLI) and grey cell coefficient (GCC) are different parameters correlated to the volume density of cellular elements in nervous tissue. The grey cell coefficient (GCC) is defined as the volume fraction of cellular elements in a griseum (grey matter area) and is estimated by a basic stereological method (point counting) from observations in two dimensions. The grey level index (GLI), measured with an automatic image analyzer, is the areal proportion of projected profiles of all stained elements within a volume given by the area of the measuring field and the thickness of section. GLI and GCC are compared in specimens obtained by a special histological procedure, and a method to estimate volume fractions by means of GLI-measurement is described.

A quantitative approach to cytoarchitectonics. VII. The areal pattern of the cortex of the Guinea pig

The cerebral cortex of the guinea pig has been examined by means of a quantitative cytoarchitectonic method (Schleicher et al. 1978; Zilles et al. 1978a). In this method, a computer-controlled automatic image analyzer determines the grey level index of microscopic fields measuring 50 X 50 mu m in Nissl-stained sections by a systematic scanning procedure. Computer plots of serially sectioned histological slides from three hemispheres were produced by printing selected ranges of grey level indices. The delineation of cortical areas was worked out in these plots based on quantitative criteria. Cortical maps of the areal pattern were reconstructed graphically. The resulting cortical map of the guinea pig differs from that of Rose (1912), but it corresponds to the results of Friede (1960) and is in agreement with neurophysiological studies. In general, the areal pattern of the guinea pig is similar to that of the rat (Zilles et al. 1980), but there are also some differences. These differences are discussed with respect to functional considerations.

Growth of fresh volumes and spontaneous cell death in the nuclei habenulae of albino rats during ontogenesis

The growth of the nuclei habenulae medialis et lateralis of albino rats is described by monotonically increasing growth curves of fresh volumes during ontogenesis. The nucleus habenulae medialis matures earlier than the nucleus habenulae lateralis in the perinatal period. However, the two nuclei reach their final volume at about the same time. Simultaneous electron microscopic investigation reveals the phenomenon of spontaneous nerve cell degeneration within the nuclei habenulae during ontogenesis in spite of the non-overshooting growth curves for the habenular nuclei.

Similarities and differences in the cortical areal patterns of Galago demidovii (E. Geoffroy, 1796; Lorisidae, Primates) and Microcebus murinus (E. Geoffroy, 1828; Lemuridae, Primates)

The areal patterns of the telencephalic cortices of Galago demidovii and Microcebus murinus were compared. A very similar pattern was found in both species. This striking similarity is considered a further argument for the newly proposed phylogenetic relationship of cheirogaleids and galagos.

Quantitative analysis of x-ray images with a television image analyser

A method for the quantitative evaluation of X-rays is described. The image is decomposed into individual image points by a mechanical scanning procedure, and at each image point the area fraction of a measuring field not covered by silver grains is determined with an image analyzer. This parameter is interpreted as representing a value corresponding to a specific degree of film blackness. The relationship between the measured value and the X-ray absorption is described by standard curves. With the aid of an aluminum scale, the measured value can be expressed directly by the thickness of an aluminum equivalent with a corresponding X-ray absorption. Details about the adjustment of the image analyzer for detecting the silver grains, the resolution of different degrees of X-ray absorption, as well as the computer-controlled scanning procedure are described. An example demonstrates its applicability to analyze the density distribution of bony tissue around the human humero-ulnar joint. The procedure is not limited to the evaluation of X-rays, but is applicable whenever silver grains can be detected in a film layer by an image analyzer.

Biomathematical analysis of the neuronal loss in the aging human brain of both sexes, demonstrated in pigment preparations of the pars cerebellaris loci coerulei

The pars cerebellaris loci coerulei is a flat accumulation of perikarya representing a subnucleus of the locus coeruleus in the roof of the fourth ventricle of the brain in man. A quantitative study was done on this subnucleus; it comprised 67 specimens from individuals between 11 and 90 years. Nerve cell counts were performed on cleared mounted block preparations. Mathematical analysis of the data was performed using logistic growth functions. The results showed that with advancing age there is a loss of neurons in both sexes. This begins in the female approximately after age 40; in the male already at age 20 (reaching a lower value in old age). The final loss of neurons is more pronounced in the male than in the female. Male and female specimens did not differ in the total number of neurons. In both sexes the left side of the pars cerebellaris loci coerulei contained more neurons than the right.

A quantitative approach to cytoarchitectonics. VI. The areal pattern of the cortex of the albino rat

Quantitative methods were used to examine the cerebral cortex of the albino rat. A computer-controlled automatic image analyzer was used to determine by a systematic scanning procedure the grey level index of the 60 X 60 mum measuring fields in Nissl-stained serial sections form three brains. Based upon various selected thresholds or ranges of grey level indices, topographically accurate computer plots were produced, and an areal pattern of the cortex worked out according to quantitative considerations. Maps of the cytoarchitectonic areas of the cortex were reconstructed graphically. The present analysis shows a cortical pattern which differs to a great extent from Krieg's (1946) classical description, but corresponds to the degeneration studies, studies on axonal transport and neurophysiological studies of various cortical areas as described in the literature.