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Cerebellum. HE (1). 2x. Sagittal section of a rat cerebellum. Numerous cerebellar folia (L) are observed, very close to each other, separated by narrow and deep grooves (arrows) occupied by meninges. In each folium the cerebellar cortex (C) is located in the superficial zone, continuing that of one folium with that of the adjacent one. The white substance (B) runs through the centre of each folium, and ends up coming together in a central area (asterisk).
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Cerebellum. HE (2). 4x. The cerebellar folia are delimited by deep grooves (arrows) that start from the surface of the cerebellum. In each folium, the cortex (double pointed arrow) is located in the peripheral part and the central axis is occupied by white matter (B). Three well-defined layers are distinguished in the cortex, which, from surface to depth, are: molecular layer (M), Purkinje cell layer (P), and granular layer (G). (Me: meninx. V: blood vessels).
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Cerebellum. HE (3). 10x. In the cerebellar cortex, located in the most superficial part of the folium, three layers are distinguished that, from the surface to the depth, correspond to: molecular or plexiform layer (M), Purkinje cell layer (P), and granular layer (G). The white matter (B) lies deeper. (Me: meninx).
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Cerebellum. HE (4). 20x. In the cerebellar cortex, the molecular or plexiform layer (M) is characterized by having a low density of nuclei, which are separated by wide spaces occupied by cell processes, hence the name plexiform. Deeper are the large somas of Purkinje (P) neurons organized in a single row. Below the Purkinje somas, the granular layer (G) is observed, which is characterized by having a large number of small heterochromatic nuclei. This layer is directly related to the white matter (B).
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Cerebellum. HE (5). 40x. The molecular layer (M) is characterized by having a low density of nuclei, which mostly belong to stellate neurons. Those closest to the surface are from superficial stellate neurons (E), while the deepest are from basket (C) (or deep stellate) neurons. In the spaces between the neuronal somas of the molecular layer, there are narrow light bands (arrowheads), with a sinuous trajectory, which can possibly correspond to dendrites of Purkinje neurons. Purkinje (P) neurons have a pyriform soma, housing a large, rounded, euchromatic nucleus with a striking nucleolus (arrows). These neurons are arranged in a single row between the molecular layer and the granular layer (G).
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Cerebellum. HE (6). 100x. Purkinje neuron seen at high magnification. It has a very large, piriform soma, with a voluminous, rounded euchromatic nucleus and a highly developed nucleolus (red arrow). In the cytoplasm, there are small basophilic granulations that correspond to Nissl bodies (arrowhead). Although it is not very frequent to observe it with routine techniques, we can see how a thick dendrite (blue arrows) arises from the upper portion of the soma, which rises and branches in the molecular layer (M). (G: granular layer).
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Cerebellum. HE (7). 40x. The granular layer (G), located immediately below the Purkinje somas (P), is characterized by having a large number of small heterochromatic nuclei. They correspond to the nuclei of the cerebellar granule cells, which are small neurons, very abundant in the cerebellar cortex. Among the nuclei of the grains there are small eosinophilic spaces (asterisks) where the cerebellar glomeruli are located (spaces where a large number of synaptic contacts are concentrated). Occasionally large neurons are found, similar to Purkinje neurons, corresponding to Golgi cells (arrow). The white matter (B) lies deeper.
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Cerebellum. HE (8). 100x. Golgi cells (arrow) located in the granular layer, in a superficial position, near the Purkinje somas (P). They are large neurons, with a rounded nucleus with some notch (red arrowhead), euchromatin and nucleolus (blue arrowhead) that are very evident. The slightly larger spaces (asterisks) between the nuclei of the grains are where the cerebellar glomeruli are located. (C: longitudinally sectioned capillary showing an endothelial cell nucleus (e). P: Purkinje neuron).
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Cerebellum. Cresyl violet (1). 4x. Cresyl violet is a basic dye that stains Nissl bodies and cell nuclei. In this sagittal section of the cerebellum, the poor coloration of the molecular or plexiform layer (M) stands out in the cortex, which contrasts with the intense staining of the granular layer (G). The white matter (B) is little stained and, in it, a set of neurons (arrow) that correspond to the deep cerebellar nuclei can be observed. (IV: fourth ventricle. P: choroid plexus).
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Cerebellum. Cresyl violet (2). 10x. Cross-sectioned cerebellar folium showing a molecular layer (M) with few nuclei, a row of Purkinje somas (arrow), and a granular layer (G) intensely stained. In the centre of the folium is the white matter (B), with few nuclei corresponding to glial cells.
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Cerebellum. Cresyl violet (3). 20x. In the cerebellar cortex stained with cresyl violet, the high density of small dark nuclei in the granular layer (G) stands out, observing among them some soma of Golgi cells (arrowhead). Above the grains, appear the row of Purkinje neuron somas (P), containing fine and coarse Nissl bodies. In the molecular layer (M) there is few nuclei, which mainly correspond to stellate neurons, both superficial and deep or basket cells. (B: white matter).
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Cerebellum. Cresyl violet (4). 40x. Coarse and fine Nissl bodies in Purkinje neurons (P) stained with cresyl violet. It is common to find a coarse Nissl body above the nucleus, forming a small cap (arrowheads). The large nucleolus (arrow) that contains the nucleus of Purkinje neurons is also visible. The clear spaces (asterisk) between the grains are where the cerebellar glomeruli are located. (C: capillary. B: white matter).
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Cerebellum. Cresyl violet (5). 100x. High-magnification detail of two Purkinje neurons (P). With this technique, the presence of both fine and coarse Nissl bodies in the same neuron stands out. At this magnification, some small invaginations (arrowheads) of the nuclear envelope are identified, occupied by the coarse Nissl body above the nucleus. Also notable is the large nucleolus (arrow) present in a large euchromatic nucleus (N). (M: molecular layer. G: granular layer. C: blood capillary).
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Cerebellum. Cresyl violet (6). 100x. High magnification of the granular layer. Among the abundant granule cells (g) with a small heterochromaic nucleus, there is a Golgi cell (arrow). It is a large neuron, similar to a Purkinje neuron, with a large euchromatic nucleus and a highly developed nucleolus (arrowhead). Cresyl violet reveals the presence of Nissl bodies of different sizes in its cytoplasm. (C: blood capillary).
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Cerebellum. Klüver-Barrera (1). 2x. This technique uses two dyes: luxol blue that stains myelin in blue colour, and cresyl violet that stains the nuclei and Nissl bodies. In this image, the bright blue staining of the white matter (B) stands out, due to its high content of myelin fibres, which extends and forms the central axis (asterisk) in each cerebellar folium (double-pointed arrow). In the cortex, the high concentration of small dense chromatin nuclei in the granular layer (G) stands out.
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Cerebellum. Klüver-Barrera (2). 4x. Union of two cerebellar folia, showing the brilliant blue staining of the myelin fibres that form the white matter (B) of the folium axis. These myelin fibres come together in a region of abundant white matter (asterisk). The cortex is located on the periphery and, with this technique, the staining of the granular layer (G) with cresyl violet stands out, due to the high concentration of nuclei, which contrasts with the scarce staining of the molecular layer (M).
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Cerebellum. Klüver-Barrera (3). 10x. When the boundary between the white matter and the gray matter in the cerebellar foilium is observed in detail, it can be seen how there are myelin fibers (arrows) stained blue with luxol blue, which penetrate the cortex, reaching the granular layer (G), but not exceeding the row of the Purkinje neuron somas (P). The lines that are stained in light blue colour (arrowheads) in the molecular layer correspond to blood capillaries with red blood cells inside.
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Cerebellum. Klüver-Barrera (4). 20x. With the Klüver-Barrera technique, myelin fibres (arrows) can be seen in the granular layer of the cerebellar cortex. These fibres correspond either to axons of Purkinje neurons that leave the cortex towards the white matter, or to climbing fibres and mossy fibres that reach the cortex from the white matter. (P: Purkinje neuron somas. G: Golgi neuron somas).
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Cerebellum. Klüver-Barrera (5). 40x. High magnification of the granular layer, showing myelin fibers (arrows) stained blue (by luxol blue), that never exceed the row of Purkinje somas (P). These fibres correspond to either Purkinje neuron axons, climbing fibres or mossy fibres. In the Purkinje neurons, the Nissl bodies (arrowhead) stained with cresyl violet, a dye that is also used in this technique. (G: Golgi neuron).
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Cerebellum. Silver stain (1). 4x. The silver nitrate technique mainly stains the neurofibrils. In the cerebellum it reveals the somas of Purkinje neurons and faintly stains their dendrites. However, the axons of the basket cells which surround the Purkinje somas, as well as the climbing fibers, will be intensely stained. The image shows the row of Purkinje neuron somas (P) and the abundance of axons in the granular layer (G), as well as in the white matter (B).
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Cerebellum. Silver stain (2). 10x. High magnification of a cross-sectioned cerebellar folium. With the silver nitrate technique, there are a high concentration of axons near Purkinje neurons (P), corresponding to the basket cells axons. Likewise, numerous axons (arrows) are observed in the granular layer (G) and in the white matter (B). The thick brown lines that appear in the molecular layer are the dendritic ramifications of Purkinje neurons.
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Cerebellum. Silver stain (3). 20x. The axons (red arrows) of basket cells are concentrated in the deepest half of the molecular layer (M), appearing as fibrillar structures arranged in parallel above the somas of Purkinje neurons (P). The baskets (arrowheads) correspond to the branches that surround each Purkinje soma, to concentrate on the area of axon hillock (blue arrows). (G: granular layer. B: white matter).
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Cerebellum. Silver stain (4). 40x. The baskets in the cerebellar cortex correspond to a set of axonal collaterals of basket axon neurons. These collaterals surround the somas of Purkinje neurons, and are most easily seen when the section plane affects tangentially these somas (arrows). The axons that make up the baskets end up concentrating in the axon hillock (arrowheads) of the Purkinje neurons, where they make inhibitory synapses. The axons of the basket neurons are organized in parallel (asterisks), above the Purkinje somas, in the deepest half of the molecular layer (M). This arrangement can only be observed when the folium is cross-sectioned. The axons of basket axon neurons are often confused with parallel fibres (axons of granule cells), but parallel fibers are arranged perpendicular to the axons of the baskets, and in the plane of section of the image would be cut crosswise and would be seen as dots. (G: granular layer).
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Cerebellum. Silver stain (5). 100x. With the silver nitrate technique, the climbing fibres are also observed. They are identified as fine dark fibres (arrows) that accompany the dendrites of Purkinje neurons, which branch off into the molecular layer (M) and appear as thick orange lines (red arrowheads). Axons (C) of basket axon neurons are also seen, including the branch point (blue arrowheads) of axonal collaterals. (G: granular layer).
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Cerebellum. Silver chromate stain (1). 2x. The Golgi technique of silver chromate is a very capricious technique, so there are areas of the section with many stained cells (arrow) compared to others without visible cells (asterisk). Many times the stained cells can be found isolated on a pale background. The advantage of this technique is that the cell that is stained does it completely, even its finest branches. The images to be described below come from different sections.
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Cerebellum. Silver chromate stain (2). 10x. Purkinje neuron showing a thick dendritic trunk (arrow) emerging from the soma, which branches out profusely in the molecular layer (M). The axon (arrowhead) originates from the opposite end of the soma, being stained along part of its path in the granular layer (g), to finally go to the white matter (with this technique the axon is no longer impregnated when it is myelinated). (Asterisks: Purkinje somas not impregnated with silver.
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Cerebellum. Silver chromate stain (3). 100x. High magnification showing the soma (S) and dendrites of a Purkinje neuron. A thick dendritic trunk (asterisk) emerges from the upper end of the soma, and is divided into numerous branches that progressively decrease in calibre. The primary dendritic trunk is devoid of spines, the thicker branches have short spines (arrows) that go unnoticed, while the finer branches contain numerous spines (arrowheads) in close proximity to one another. (Purkinje cells are one of the neurons with the largest number of spines in the CNS. They can have between 100,000 and 250,000 per neuron).
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Cerebellum. Silver chromate stain (4). 10x. Region of the cerebellar cortex showing several Purkinje neurons (P). The broad dendritic trees (arrows) of the different neurons overlap each other. The dendritic trees of Purkinje neurons are arranged in a single plane, transversal to the cerebellar folium. One of the neurons shows the origin of the axon (arrowhead), directed towards the granular layer (g). (B: white matter).
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Cerebellum. Silver chromate stain (5). 20x. Superficial (Es) and deep (Ep) stellate neurons located in the molecular layer of the cerebellar cortex. Superficial stellate cells are located in the most superficial half of the plexiform layer. They have a small soma with long and little branched dendrites (red arrows), always located in the molecular layer. The image shows a short path of the axon (red arrowhead). The deep stellate or basket cells have a larger soma, with dendrites (blue arrows) also long, running through the molecular layer in the transverse plane of the folium (parallel to the dendritic tree of Purkinje neurons), without exceeding the row of the Purkinje somas. This image does not show the axon of these neurons (see following images).
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Cerebellum. Silver chromate stain (6). 20x. Axons of basket cells. They are long axons located in the deepest portion of the molecular layer (M). They are located above and parallel to the Purkinje somas, covering a long path (about 10 Purkinje neuron somas). On their way they emit collaterals (arrows) towards the somas of the Purkinje neurons, encompassing them to form the baskets (C) and concentrating on the origin of the axon in the so-called brush (arrowhead). The dendrites of the basket cells are located in the transverse plane of the folium, like the dendritic tree of the Purkinje neurons, exerting a powerful inhibition on these neurons. (g: layer of the grains. B: white matter).
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Cerebellum. Silver chromate stain (7). 40x. Detail of the baskets that surrounds the soma of the Purkinje neurons (P). The brush (asterisk) is clearly distinguished, formed by the axonal collaterals of basket cells axon that converge in the axon hillock of Purkinje neurons, where they exert a powerful inhibitory action. The axon path (arrowheads) of the basket cells, above the Purkinje neurons, is also visible, including the point where the axonal collaterals (arrow) emerge. The parallel arrangement of these axons should not be confused with the parallel fibres (axons of granule cells), which, as are arranged perpendicular to the axons of the basket cells, would be seen in this section plane as points and not like lines. (g: granular layer. B: white matter).
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Cerebellum. Silver chromate stain (8). 20x. Candelabrum cell (C). Their soma is located immediately above the somas of Purkinje neurons (P). Dendrites (arrow) originate from the soma, most of which are directed towards the molecular layer (M), generally following an upward and relatively rectilinear path. In the molecular layer, some parallel fibres are identified (arrowheads), which indicates that the folium is longitudinally sectioned. (g: granular layer).
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Cerebellum. Silver chromate stain (9). 40x. Granular layer (G) where a few grains have been stained. They are small neurons, with rounded soma, with three to five short dendrites that branch only at their end, forming a structure that resembles a claw (arrows). It is only at this end that the grains receive synaptic contacts in the cerebellar glomerulus. In one grain it can see the origin of the axon (red arrowhead) starting from the soma, while in another (blue arrowhead) it arises from a dendrite.
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Cerebellum. Silver chromate stain (10). 40x. Several stained granule cells in the granular layer (g). In some regions (arrow) the claw-like ends of the dendrites of the granule cells come together in areas corresponding to the cerebellar glomeruli. They are places where numerous synaptic contacts are concentrated. Specifically, the grains receive stimuli from both the rosette of the mossy fibers and the axons of the Golgi neurons (none are seen in the image). The large neuron (C) located between non-stained Purkinje (P) somas is a candelabrum cell that emits a dendrite (arrowhead) that enters the territory of the granular layer.
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Cerebellum. Silver chromate stain (11). 40x. The axon (arrows) of the granule cells is systematically directed towards the molecular layer, where it divides into a “T” (arrowhead) to give rise to the parallel fibres (asterisks). These fibres are arranged in the longitudinal plane of the cerebellar folium, perpendicular to both the dendritic trees of the Purkinje neurons and the superficial and deep stellate neurons, with which they synapse. (B: branch of a Bergmann cell).
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Silver chromate stain (12). 40x. Detail of a “T” branch (asterisk) of the granule cell axon in the molecular layer (M), to form the parallel fibers (arrows). Small thickenings appear in the path of these fibers (arrowheads) that correspond, each of them, to a synaptic contact. (P: row of Purkinje neuron somas. G: granular layer).
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Cerebellum. Silver chromate stain (13). 20x. Longitudinally sectioned cerebellar folium showing numerous parallel fibres (arrows), running through the molecular layer (M). At some points (arrowhead) the T-branching of the grain axon is seen. These fibres cross a single stained Purkinje neuron dendritic tree (D), which appear laterally in the image. In the granular layer (g) there are many impregnated granule cells. (a: axon of a Purkinje neuron emerging from the soma).
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Cerebellum. Silver chromate stain (14). 20x. Golgi neurons (G). They are neurons located in the granular layer (g), with a large soma, from which long and little branched dendrites (arrows) arise. Some are located in the granular layer and others ascend to the molecular layer (M). The axon (arrowhead) is a finer extension, which branches very extensively in the territory of the granular layer (see next image). (B: white matter).
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Cerebellum. Silver chromate stain (15). 40x. Axon of a Golgi cell located in the granular layer (g). It is a fine axon (arrow), which branches out profusely, covering a wide territory, without leaving the granular layer. On its way, it presents small thickenings (arrowheads), each corresponding to synaptic contacts with the dendrites of the granular cells in the cerebellar glomerulus. (P: unstained Purkinje neuron somas. B: white matter).
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Cerebellum. Silver chromate stain (16). 20x. Lugaro's neurons are generally located in the most superficial part of the granular layer (g). They have an ovoid or fusiform soma (arrow), where long dendrites (arrowheads) emerge from its ends that follow a path parallel to the somas of Purkinje neurons (P). (M: molecular layer. B: white matter).
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Cerebellum. Silver chromate stain (17). 40x. A unipolar brush neuron, isolated, located in the granular layer. They are neurons with a small piriform soma (s), with a single thick dendritic process (arrow), which ends up widening and emitting multiple and short extensions, called dendrioles (arrowheads), which are responsible for the "brush" appearance. (M: molecular layer. P: somas of unstained Purkinje neurons).
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Cerebellum. Silver chromate stain (18). 20x. Mossy fibers (m) located in the granular layer (g). These fibres never ascend to the molecular layer. Mossy fibres are characterized by presenting thicknesses of irregular contour on their way, corresponding to the so-called rosettes (arrows). These rosettes make synapses mainly with the granule cells dendrites, constituting the centre of the cerebellar glomeruli. Groups of cells, difficult to distinguish, have been stained in the granular layer, appearing as irregular black spots. (M: molecular layer. P: soma of impregnated Purkinje neurons. B: white matter).
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Cerebellum. Silver chromate stain (19). 40x. Bergmann glia are a special type of astrocytes, typical of the cerebellar cortex. They have a small soma (arrow), located among the somas of Purkinje neurons, from which six to eight extensions emerge that always go towards the surface of the cerebellar cortex, ending in a small widening that is part of the glia limitans (asterisk). The surface of the Bergmann glial branches have irregular thickenings (arrowheads), because they isolate the multitude of synapses found in the molecular layer (M). (g: granular cells. P: pericyte embracing and integrated into the wall of a blood capillary).
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Immature cerebellum. HE (1). 2x. Immature cerebellum in the postnatal period. The cerebellar folia are well defined and developed. What allows us to know that it is immature is the presence of an external granular layer (arrows) located on the surface of the cerebellar cortex.
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Immature cerebellum. HE (2). 4x. Folded cerebellar folia in an immature cerebellum. The existence of an accumulation of small nuclei located on the surface of the cortex, which corresponds to the external granular layer (asterisk), is striking. Immediately below is the molecular layer (M) and deeper, near to the white matter (B), the inner granular layer (Gi).
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Immature cerebellum. HE (3). 10x. Cerebellar folia in an immature cerebellum. As in the adult cerebellum, the cortex is located on the periphery; however, when the cerebellum is not fully developed, an outer granular layer (asterisk) is found above the molecular layer (M). The row of the Purkinje somas (P) is perfectly defined and, more deeply, the inner granular layer (Gi) is located. In the centre of the folium there is a narrow axis of white matter (B).
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Immature cerebellum. HE (4). 20x. Cerebellar cortex in an immature cerebellum. The most characteristic feature of the immature cortex is the presence of an external granular layer (asterisk). This layer is made up of immature grains, where they divide by mitosis (arrowhead), to later migrate crossing the molecular layer (M) and the row of the Purkinje somas, to reach their final position in the inner granular layer (Gi). An example of this migration is the presence of fusiform nuclei (arrows) in the molecular layer. When the maturation of the cerebellum ends, the outer granular layer disappears after all the grains have migrated to the inner granular layer, which is now simply called the granular layer.
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Cerebral cortex. HE (1). 2x. Low magnification image showing two cerebral gyri (C), separated by a relatively deep sulcus, occupied by the meninx (M). The cerebral cortex (double-headed arrow) is located in the periphery of the brain, and continues from one gyrus to the next. In the centre of each convolution, in a deeper position, is the white matter (B). Covering the surface of the cerebral cortex are the leptomeninges: arachnoid (A) and pia mater (attached to the brain surface); between both, the subarachnoid space (asterisk) can be seen.
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Cerebral cortex. HE (2). 4x. Although they are not always clearly distinguished, the cerebral cortex is organized in six layers, according to the arrangement of the neuronal somas. The image identifies the molecular layer or layer I (I) and, more deeply, a predominance of pyramidal neuron somas in a columnar arrangement is observed. This indicates that this cortex corresponds to a motor region. Blood vessels (V) are found surrounded by a clear space (arrowheads), the Virchow-Robin space, which is slightly enlarged as a consequence of the histological technique. The surface of the cortex is covered by the meninx: arachnoid (A), subarachnoid space (asterisk), and pia mater (arrow). (v: blood vessel in the subarachnoid space. B: white matter).
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Cerebral cortex. HE (3). 10x. The molecular or layer I (double-headed arrow) is the most superficial portion of the cerebral cortex, characterized by the low nuclear density. The penetration of an arteriole (red arrow) into the cerebral cortex from the subarachnoid space and the exit of a small vein (blue arrow) are observed. Deeper are pyramidal neurons (P) with a columnar organization. (V: blood vessels in the subarachnoid space).
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Cerebral cortex. HE (4). 20x. Detail of the previous figure showing the entrance of a small arteriole (A) that starts from the meninx, being located in the layer I or molecular layer (double pointed arrow). Around this blood vessel, there is a small space corresponding to the Virchow-Robin space (arrowhead). The few somas in this layer belong to horizontal or Cajal-Retzius neurons or to glial cells. The somas of pyramidal neurons are located deeper. (Arrow: pia mater. V: blood vessel in the subarachnoid space).
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Cerebral cortex. HE (5). 20x. Region of the cerebral cortex immediately below the molecular layer, or layer I (I). It is known to be a motor cortex, as the pyramidal cells are the predominant neuronal type. This region would be equivalent to layers II-III (external granular and external pyramidal layers). Among the somas of the pyramid cells are small blood capillaries (arrow).
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Cerebral cortex. HE (6). 40x. Of the multiple neuronal types that make up the cerebral cortex, the only neurons that can be clearly identified are the pyramidal cells (P). They have a triangular soma (in three-dimensions it has a conical shape) with a typical large rounded neuronal euchromatic nucleus (arrow) and a developed nucleolus. In their cytoplasm, with HE, relatively thick Nissl (red arrowhead) bodies are identified. Some neurons have glial cells close to the soma, causing a small imprint: they are the so-called satellite glial cells (blue arrowhead) (they are usually oligodendrocytes, although the one indicated in the image appears to be a microglial cell). Among the neuronal somas are blood capillaries (C), some of which have a clear space around them, an artifact that appears frequently in the nervous tissue.
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Cerebral cortex. HE (7). 40x. Somas (arrows) of pyramidal neurons in a motor cerebral cortex, with their typically triangular shape. It is possible to appreciate how a dendrite (d) arises from the soma, which appears as a narrow clear band that follows a rectilinear path, to go to the molecular layer. The soma contains a large, loose chromatin nucleus with a developed nucleolus. A basophilic cytoplasm is observed around the nucleus due to the presence of Nissl bodies. Among the neuronal somas, blood capillaries (C) are distinguished, showing a small halo (arrowheads) around them, a frequent artifact in the nervous tissue. (Red arrowhead: protoplasmic astrocyte nucleus).
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Cerebral cortex. HE (8). 10x. Deep area of the cortex showing polymorphic neurons of layer VI (VI) near the white matter (B). The white matter has a different aspect to that of the cortex, acquiring a fibrillar appearance, without neuronal somas, showing numerous small nuclei arranged in rows that correspond to glial cells: mainly oligodendrocytes, but also fibrous astrocytes and some microglial cell.
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Cerebral cortex. HE (9). 20x. Detail of the limit between the cerebral cortex (C) and the white matter (B). In the deep areas of the cortex, neuronal somas of the layer VI or polymorphic cells are identified. In the white matter the neuronal somas disappear and small nuclei corresponding to astrocytes, oligodendrocytes and some microglial cell are observed. (Arrows: blood capillaries).
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Cerebral cortex. HE (10). 20x. Located immediately below the cortex (C) is the white matter. It lacks neuronal somas, it has a finely fibrillar appearance, showing small, perfectly aligned nuclei chains (asterisks). Although this arrangement is typical of oligodendroglia (dense, round nucleus, blue arrowhead), fibrous astrocytes (paler nucleus, red arrowhead) also intervene.
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Cerebral cortex. Cresyl violet (1). Low magnification image of a parasagittal cut of a rabbit brain showing the two types of the cerebral cortex (double-headed arrow): the neocortex or isocortex (motor cortex -m-, association cortex -a- and sensory cortex -s-), and also an example of allocortex such as the hippocampus (H). The quadrigeminal tubercles (T) belonging to the midbrain, the pineal gland (P) and the cerebellum (Cb) are also distinguished.
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Cerebral cortex. Cresyl violet (2). 2x. Low magnification image of the brain where you can distinguish how the organization of the cortex layers changes according to the different cortical regions. The cresyl violet technique allows us to better see the somewhat diffuse organization of the layers of the cerebral cortex when compared to other routine techniques such as HE. In the neocortex, the region that predominates, it is identified from left to right: a motor cortex (M), which continues with an associative cortex (A) and in the occipital lobe changes to a sensory cortex (S). Also noteworthy is the hippocampus (H), an example of allocortex (less abundant and older from an evolutionary point of view than the neocortex). (V: lumen of the lateral ventricle).
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Cerebral cortex. Cresyl violet (3). 4x. Associative cerebral cortex showing the organization of the neuronal somas in six layers: layer I or molecular, with a small number of nuclei; layer II or external granular, formed by small pyramids; layer III or internal pyramidal, with medium and large pyramids; layer IV or internal granular; layer V or internal pyramidal with giant pyramids; and layer VI or polymorphic neurons. (B: white matter).
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Cerebral cortex. Cresyl violet (4). 10x. Motor cortex showing the most superficial layers: I, II and III. As is characteristic of this type of cortex, pyramidal neurons (arrowheads) predominate in layers II and III, while in layer I there is a scarce nuclear density. (Arrow: meninges).
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Cerebral cortex. Cresyl violet (5). 20x. Detail of the motor cortex, where pyramidal neurons (P) predominate, located at different heights. These cells show a large rounded euchromatic nucleus, with a developed nucleolus. Cresyl violet stains the Nissl bodies that fill the cytoplasm. In some neurons, the origin of the apical dendrite can be seen (arrowheads).
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Cerebral cortex. Cresyl violet (6). 40x. Large pyramidal (P) neurons of a motor cerebral cortex. They have a triangular soma with a large euchromatic nucleus (N), of and an evident nucleolus. In the cytoplasm, the presence of thick Nissl bodies (arrowheads) is visible with this technique, some of them extending through the apical dendrite (asterisk). Among the pyramids are other smaller nuclei stained (arrows), with a chromatin of different aspect, which correspond to different types of glial cells. (V: blood vessel).
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Cerebral cortex. Cresyl violet (7). 4x. In the sensitive cerebral cortex, granular layers II and IV predominate, with pyramidal layers (III and V) being poorly developed. (I: layer I or molecular. VI: layer VI or polymorphic neurons. B: white matter).
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Cerebral cortex. Cresyl violet (8). 10x. Superficial layers of a sensitive cerebral cortex. The molecular layer (layer I) is thick and, more deeply, there is a layer II whit a high density of small neurons. Layer III is barely developed, with some isolated medium pyramids (arrows) located among smaller neurons. Layer IV is made up of numerous small neurons, and layer V contains scarce number of large neurons (arrowheads). (V: blood vessels in the subarachnoid meningeal space).
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Cerebral cortex. Cresyl violet (9). 40x. Detail of layers II and III of a sensitive cerebral cortex. The small somas of neurons (arrowheads) that make up layer II predominate, while the pyramids (arrows) of layer III are very few and intermingle with neurons of layer II. In the upper part of the image the deepest part of layer I is identified, where very few cell somas are observed.
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Cerebral cortex. Cresyl Violet (10). 2x. Low magnification image showing the hippocampus region, as an example of allocortex (scarcer and evolutionarily older). In the Ammon’s horn (with the appearance of the letter “C” open to the right) the regions CA1, CA2 and CA3 are distinguished. The CA1 region of the Ammon horn gradually narrows to form the subiculum (asterisk) and progressively continues with the cerebral cortex (arrow). The end of the CA3 region of the Ammon horn is coupled with another structure in the shape of the letter "C", open to the left and with a pointed region, the dentate gyrus (GD). (V: lateral ventricle).
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Cerebral cortex. Klüver-Barrera (1). 2x. This technique uses two dyes: luxol blue that stains myelin and cresyl violet that stains cell nuclei and Nissl bodies. In this low magnification image of a cerebral gyrus, we can see the neuronal somas of the cerebral cortex (C), but above all, the bright blue staining of the myelin fibres grouped in the white matter (B) stands out. (M: meninges).
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Cerebral cortex. Klüver-Barrera (2). 4x. This technique combines two dyes: one is cresyl violet, which reveals the neuronal somas (arrowheads) in the cerebral cortex, showing a certain columnar arrangement; the other is luxol blue, which stains the myelin fibres in bright blue colour, making the white matter stand out (B). The image shows that the boundary (dotted line) between the cortex and the white matter is diffuse, there are numerous myelin fibres (arrows) that penetrate from the white matter to the cortex, or go from the cortex to the white matter. In both cases, these fibres are vertically oriented. (V: blood vessels located in the subarachnoid meningeal space).
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Cerebral cortex. Klüver-Barrera (3). 4x. This technique demonstrates the arrangement of abundant myelin fibres in the cerebral cortex. Most of the fibres are oriented vertically (arrows), concentrating in the deepest regions of the cortex, in the vicinity of the white matter. To a lesser extent, there are fibres that are arranged horizontally (arrowheads). (I: layer I. M: meninx).
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Cerebral cortex. Klüver-Barrera (4). 10x. In the deeper areas of the cerebral cortex, there are abundant myelin fibres, arranged vertically (arrows). These are both fibres that enter the cortex from the white matter (B) (cortical afferences that come mainly from other territories of the cortex and the thalamus) and the axons of the pyramid cells (arrowheads) emerging from the cortex into the white matter. There may be, to a lesser extent, myelinated fibres that are arranged horizontally or obliquely (asterisks).
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Cerebral cortex. Klüver-Barrera (5). 20x. High magnification image of the cerebral cortex showing the different neuronal somas. Those of greater size and triangular shape correspond to pyramids (P). In its soma there is a large euchromatic nucleus and a developed nucleolus, and a cytoplasm with numerous Nissl bodies stained in violet colour. The origin of some dendrites can be seen (arrowheads). Among the somas, the presence of blue-stained myelin fibres stands out, most of them arranged vertically (blue arrows), although other less numerous fibres that run horizontally (red arrows) are also seen.
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Cerebral cortex. Silver chromate stain (1). 4x. The silver chromate or Golgi technique is a very capricious silver technique, in the sense that an indeterminate and highly variable number of cells are stained in the nervous tissue, but these cells does so in its entirety, up to the finer processes. In the cerebral cortex (double-headed arrow) shown in the image, impregnation of pyramidal neurons or pyramids (arrows) predominates, the most abundant and characteristic neuron of the cerebral cortex. In the white matter (B) few fibrous astrocytes have been stained (arrowhead).
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Cerebral cortex. Silver chromate stain (2). 10x. The somas of the pyramidal neurons (arrows) of the cerebral cortex have a triangular shape and are located at different heights. Regardless of the position of the pyramids, a dendrite emerges from the vertex of the soma, the apical dendrite (red arrowheads), which follows a rectilinear path to reach layer I (double-pointed arrows). A group of dendrites corresponding to the basal or basilar dendrites (blue arrowheads) emerge from the base of the pyramid soma. Among the neuronal somas there is a network, more or less lax, of fine extensions (asterisk), corresponding to processes of different neurons of the cerebral cortex.
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Cerebral cortex. Silver chromate stain (3). 20x. Group of four pyramidal neurons located in the same layer (layer V), which have been stained with the Golgi method. They have a triangular shape soma, from whose vertex the apical dendrite (red arrows) arise, which systematically goes towards layer I, following a rectilinear path. Numerous basilar dendrites (blue arrows) emerge from the base of the soma and radiate in all directions. The origin of the axon (arrowheads) is also appreciated in three of the impregnated pyramids. Among the pyramidal somas there are numerous processes (asterisk) of other neurons.
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Cerebral cortex. Silver chromate stain (4). 40x. High-magnification detail of the soma of a large pyramidal neuron of the cerebral cortex. It has a triangular shape, and two groups of dendrites arise from the vertices: a thick apical dendrite (arrow) emerge from the upper vertex, which follows an upward rectilinear path and reaches layer I of the cortex; and a set of finer dendrites originates from the base of the soma, the basal or basilar dendrites (arrowheads), which project in all directions at a short distance. Around this pyramid numerous processes of other neurons are observed.
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Cerebral cortex. Silver chromate stain (5). 10x. Pyramids (P) of the cerebral cortex, showing the behaviour of the apical dendrite(arrows) of two pyramids. This trunk arises from the vertex of the soma, it follows an upward rectilinear course until reaching layer I, where it branches and forms a wide dendritic plexus (asterisk). Basilar or basal dendrites (arrowheads) that emerge from the base of the soma are also observed. They are more numerous dendrites, but shorter.
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Cerebral cortex. Silver chromate stain (6). 40x. Detail of the apical dendrite of the pyramidal neurons of the cerebral cortex. There are numerous dendritic spines (arrowheads) arising from the surface of the dendrite as fine protrusions ending in a small thickening or spine head. Each dendritic spine receives at least one synaptic contact.
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