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http://rgm22.nig.ac.jp/mediawiki-ogareport/index.php/For_Gray_anatomy_normalization
 * 2. The transverse or commissural fibers connect the two hemispheres. They include: (a) the transverse fibers of the corpus callosum, (b) the anterior commissure, (c) the posterior commissure, and (d) the lyra or hippocampal commissure; they have already been described.
 * 3. The association fibers (Fig. 751) unite different parts of the same hemisphere, and are of two kinds: (1) those connecting adjacent gyri, short association fibers; (2) those passing between more distant parts, long association fibers.	  142
 * The short association fibers lie immediately beneath the gray substance of the cortex of the hemispheres, and connect together adjacent gyri.	  143
 * The long association fibers include the following: (a) the uncinate fasciculus; (b) the cingulum; (c) the superior longitudinal fasciculus; (d) the inferior longitudinal fasciculus; (e) the perpendicular fasciculus; (f) the occipitofrontal fasciculus; and (g) the fornix.	  144
 * (a) The uncinate fasciculus passes across the bottom of the lateral fissure, and unites the gyri of the frontal lobe with the anterior end of the temporal lobe.	  145
 * (b) The cingulum is a band of white matter contained within the cingulate gyrus. Beginning in front at the anterior perforated substance, it passes forward and upward parallel with the rostrum, winds around the genu, runs backward above the corpus callosum, turns around the splenium, and ends in the hippocampal gyrus.	  146
 * (c) The superior longitudinal fasciculus passes backward from the frontal lobe above the lentiform nucleus and insula; some of its fibers end in the occipital lobe, and others curve downward and forward into the temporal lobe.	  147
 * (d) The inferior longitudinal fasciculus connects the temporal and occipital lobes, running along the lateral walls of the inferior and posterior cornua of the lateral ventricle.
 * (e) The perpendicular fasciculus runs vertically through the front part of the occipital lobe, and connects the inferior parietal lobule with the fusiform gyrus.	  149
 * (f) The occipitofrontal fasciculus passes backward from the frontal lobe, along the lateral border of the caudate nucleus, and on the mesial aspect of the corona radiata; its fibers radiate in a fan-like manner and pass into the occipital and temporal lobes lateral to the posterior and inferior cornua. Déjerine regards the fibers of the tapetum as being derived from this fasciculus, and not from the corpus callosum.	  150
 * (g) The fornix connects the hippocampal gyrus with the corpus mammillare and, by means of the thalamomammillary fasciculus, with the thalamus (see page 839). Through the fibers of the hippocampal commissure it probably also unites the opposite hippocampal gyri.	  151
 * The gray substance of the hemisphere is divided into: (1) that of the cerebral cortex, and (2) that of the caudate nucleus, the lentiform nucleus, the claustrum, and the nucleus amygdalæ.	  152
 * Structure of the Cerebral Cortex (Fig. 754).—The cerebral cortex differs in thickness and structure in different parts of the hemisphere. It is thinner in the occipital region than in the anterior and posterior central gyri, and it is also much thinner at the bottom of the sulci than on the top of the gyri. Again, the minute structure of the anterior central differs from that of the posterior central gyrus, and areas possessing a specialized type of cortex can be mapped out in the occipital lobe.	  153
 * On examining a section of the cortex with a lens, it is seen to consist of alternating white and gray layers thus disposed from the surface inward: (1) a thin layer of white substance; (2) a layer of gray substance; (3) a second white layer (outer band of Baillarger or band of Gennari); (4) a second gray layer; (5) a third white layer (inner band of Baillarger); (6) a third gray layer, which rests on the medullary substance of the gyrus.	  154
 * The cortex is made up of nerve cells of varying size and shape, and of nerve fibers which are either medullated or naked axis-cylinders, imbedded in a matrix of neuroglia.	  155
 * Nerve Cells.—According to Cajal, the nerve cells are arranged in four layers, named from the surface inward as follows: (1) the molecular layer, (2) the layer of small pyramidal cells, (3) the layer of large pyramidal cells, (4) the layer of polymorphous cells.	  156
 * The Molecular Layer.—In this layer the cells are polygonal, triangular, or fusiform in shape. Each polygonal cell gives off some four or five dendrites, while its axon may arise directly from the cell or from one of its dendrites. Each triangular cell gives off two or three dendrites, from one of which the axon arises. The fusiform cells are placed with their long axes parallel to the surface and are mostly bipolar, each pole being prolonged into a dendrite, which runs horizontally for some distance and furnishes ascending branches. Their axons, two or three in number, arise from the dendrites, and, like them, take a horizontal course, giving off numerous ascending collaterals. The distribution of the axons and dendrites of all three sets of cells is limited to the molecular layer.	  157
 * The Layer of Small and the Layer of Large Pyramidal Cells.—The cells in these two layers may be studied together, since, with the exception of the difference in size and the more superficial position of the smaller cells, they resemble each other. The average length of the small cells is from 10 to 15μ; that of the large cells from 20 to 30μ. The body of each cell is pyramidal in shape, its base being directed to the deeper parts and its apex toward the surface. It contains granular pigment, and stains deeply with ordinary reagents. The nucleus is of large size, and round or oval in shape. The base of the cell gives off the axis cylinder, and this runs into the central white substance, giving off collaterals in its course, and is distributed as a projection, commissural, or association fiber. The apical and basal parts of the cell give off dendrites; the apical dendrite is directed toward the surface, and ends in the molecular layer by dividing into numerous branches, all of which may be seen, when prepared by the silver or methylene-blue method, to be studded with projecting bristle-like processes. The largest pyramidal cells are found in the upper part of the anterior central gyrus and in the paracentral lobule; they are often arranged in groups or nests of from three to five, and are named the giant cells of Betz. In the former situation they may exceed 50μ in length and 40μ in breadth, while in the paracentral lobule they may attain a length of 65μ.	  158
 * Layer of Polymorphous Cells.—The cells in this layer, as their name implies, are very irregular in contour; they may be fusiform, oval, triangular, or star-shaped. Their dendrites are directed outward, but do not reach so far as the molecular layer; their axons pass into the subjacent white matter.	  159
 * There are two other kinds of cells in the cerebral cortex. They are: (a) the cells of Golgi, the axons of which divide immediately after their origins into a large number of branches, which are directed toward the surface of the cortex; (b) the cells of Martinotti, which are chiefly found in the polymorphous layer; their dendrites are short, and may have an ascending or descending course, while their axons pass out into the molecular layer and form an extensive horizontal arborization.

after
2. The transverse or commissural fibers connect the two hemispheres. They include: (a) the transverse fibers of the {corpus callosum [FMA61946:Genu of corpus callosum; FMA61947:Body of corpus callosum; FMA86464:Corpus callosum]}, (b) the {anterior commissure [FMA61961:Anterior commissure]}, (c) the {posterior commissure [FMA62072:Posterior commissure]}, and (d) the lyra or {hippocampal commissure [FMA61970:Commissure of fornix of forebrain]}; they have already been described. 3. The association fibers (Fig. 751) unite different parts of the same hemisphere, and are of two kinds: (1) those connecting adjacent gyri, short association fibers; (2) those passing between more distant parts, long association fibers. 142   The short association fibers lie immediately beneath the {gray substance [FMA67242:Gray matter of neuraxis]} of the {cortex [FMA15632:Adrenal cortex; FMA61109:Cortex]} of the hemispheres, and connect together adjacent gyri. 143   The long association fibers include the following: (a) the {uncinate fasciculus [FMA77636:Uncinate fasciculus]}; (b) the {cingulum [FMA56731:Cingulum of tooth]}; (c) the {superior longitudinal fasciculus [FMA77631:Superior longitudinal fasciculus]}; (d) the {inferior longitudinal fasciculus [FMA77632:Inferior longitudinal fasciculus]}; (e) the perpendicular fasciculus; (f) the {occipitofrontal fasciculus [FMA77633:Inferior occipitofrontal fasciculus; FMA77634:Superior occipitofrontal fasciculus]}; and (g) the {fornix [FMA61965:Fornix of forebrain]}. 144   (a) The {uncinate fasciculus [FMA77636:Uncinate fasciculus]} passes across the bottom of the {lateral fissure [FMA77801:Lateral sulcus]}, and unites the gyri of the {frontal lobe [FMA61824:Frontal lobe]} with the anterior end of the {temporal lobe [FMA61825:Temporal lobe]}. 145   (b) The {cingulum [FMA56731:Cingulum of tooth]} is {a band [FMA67918:Anisotropic band]} of {white matter [FMA83929:White matter of neuraxis]} contained within the {cingulate gyrus [FMA62434:Cingulate gyrus]}. Beginning in front at the {anterior perforated substance [FMA61891:Anterior perforated substance]}, it passes forward and upward parallel with the rostrum, winds around the {genu [FMA24974:Knee]}, runs backward above the {corpus callosum [FMA61946:Genu of corpus callosum; FMA61947:Body of corpus callosum; FMA86464:Corpus callosum]}, turns around the {splenium [FMA7196:Spleen]}, and ends in the {hippocampal gyrus [FMA61918:Parahippocampal gyrus]}. 146   (c) The {superior longitudinal fasciculus [FMA77631:Superior longitudinal fasciculus]} passes backward from the {frontal lobe [FMA61824:Frontal lobe]} above the {lentiform nucleus [FMA77615:Lentiform nucleus]} and {insula [FMA67329:Insula]}; some of its fibers end in the {occipital lobe [FMA67325:Occipital lobe]}, and others curve downward and forward into the {temporal lobe [FMA61825:Temporal lobe]}. 147   (d) The {inferior longitudinal fasciculus [FMA77632:Inferior longitudinal fasciculus]} connects the temporal and {occipital lobes [FMA67325:Occipital lobe]}, running along the lateral walls of the inferior and {posterior cornua [FMA83700:Occipital horn of lateral ventricle]} of the {lateral ventricle [FMA78448:Lateral ventricle]}. (e) The perpendicular fasciculus runs vertically through the front part of the {occipital lobe [FMA67325:Occipital lobe]}, and connects the {inferior parietal lobule [FMA61897:Supramarginal gyrus; FMA77536:Inferior parietal lobule]} with the {fusiform gyrus [FMA61908:Fusiform gyrus]}. 149   (f) The {occipitofrontal fasciculus [FMA77633:Inferior occipitofrontal fasciculus; FMA77634:Superior occipitofrontal fasciculus]} passes backward from the {frontal lobe [FMA61824:Frontal lobe]}, along the lateral border of the {caudate nucleus [FMA61833:Caudate nucleus]}, and on the mesial aspect of the {corona radiata [FMA18661:Corona radiata]}; its fibers radiate in a fan-like manner and pass into the occipital and {temporal lobes [FMA61825:Temporal lobe]} lateral to the posterior and {inferior cornua [FMA83701:Temporal horn of lateral ventricle]}. Déjerine regards the fibers of the {tapetum [FMA77208:Tapetum]} as being derived from this fasciculus, and not from the {corpus callosum [FMA61946:Genu of corpus callosum; FMA61947:Body of corpus callosum; FMA86464:Corpus callosum]}. 150   (g) The {fornix [FMA61965:Fornix of forebrain]} connects the {hippocampal gyrus [FMA61918:Parahippocampal gyrus]} with the {corpus mammillare [FMA74877:Mammillary body]} and, by means of the {thalamomammillary fasciculus [FMA83849:Mammillothalamic tract]}, with the {thalamus [FMA62007:Thalamus]} (see page 839). Through the fibers of the {hippocampal commissure [FMA61970:Commissure of fornix of forebrain]} it probably also unites the opposite {hippocampal gyri [FMA61918:Parahippocampal gyrus]}. 151   The {gray substance [FMA67242:Gray matter of neuraxis]} of the hemisphere is divided into: (1) that of the {cerebral cortex [FMA61830:Cerebral cortex]}, and (2) that of the {caudate nucleus [FMA61833:Caudate nucleus]}, the {lentiform nucleus [FMA77615:Lentiform nucleus]}, the {claustrum [FMA67440:Claustrum]}, and the {nucleus amygdalæ [FMA61841:Amygdala]}. 152   Structure of the {Cerebral Cortex [FMA61830:Cerebral cortex]} (Fig. 754).—The {cerebral cortex [FMA61830:Cerebral cortex]} differs in thickness and structure in different parts of the hemisphere. It is thinner in the {occipital region [FMA67325:Occipital lobe]} than in the anterior and {posterior central gyri [FMA61896:Postcentral gyrus]}, and it is also much thinner at the bottom of the sulci than on the top of the gyri. Again, the minute structure of the anterior central differs from that of the {posterior central gyrus [FMA61896:Postcentral gyrus]}, and areas possessing a specialized type of {cortex [FMA15632:Adrenal cortex; FMA61109:Cortex]} can be mapped out in the {occipital lobe [FMA67325:Occipital lobe]}. 153   On examining a section of the {cortex [FMA15632:Adrenal cortex; FMA61109:Cortex]} with a {lens [FMA58241:Lens]}, it is seen to consist of alternating white and gray layers thus disposed from the surface inward: (1) a thin layer of {white substance [FMA83929:White matter of neuraxis]}; (2) a layer of {gray substance [FMA67242:Gray matter of neuraxis]}; (3) a second white layer (outer band of Baillarger or {band of Gennari [FMA75667:Occipital stripe of internal granular layer of neocortex]}); (4) a second gray layer; (5) a third white layer (inner band of Baillarger); (6) a third gray layer, which rests on the medullary substance of the gyrus. 154   The {cortex [FMA15632:Adrenal cortex; FMA61109:Cortex]} is made up of {nerve cells [FMA54527:Neuron]} of varying size and shape, and of {nerve fibers [FMA5914:Nerve fiber]} which are either medullated or naked {axis-cylinders [FMA67308:Axon]}, imbedded in a matrix of {neuroglia [FMA54541:Set of neuroglial cells]}. 155   {Nerve Cells [FMA54527:Neuron]}.—According to Cajal, the {nerve cells [FMA54527:Neuron]} are arranged in four layers, named from the surface inward as follows: (1) the molecular layer, (2) the layer of small {pyramidal cells [FMA84105:Pyramidal cell of cerebral cortex]}, (3) the layer of large {pyramidal cells [FMA84105:Pyramidal cell of cerebral cortex]}, (4) the layer of polymorphous cells. 156   The Molecular Layer.—In this layer the cells are polygonal, triangular, or fusiform in shape. Each polygonal cell gives off some four or five {dendrites [FMA67314:Dendrite]}, while its {axon [FMA67308:Axon]} may arise directly from the cell or from one of its {dendrites [FMA67314:Dendrite]}. Each triangular cell gives off two or three {dendrites [FMA67314:Dendrite]}, from one of which the {axon [FMA67308:Axon]} arises. The fusiform cells are placed with their long axes parallel to the surface and are mostly bipolar, each pole being prolonged into a {dendrite [FMA67314:Dendrite]}, which runs horizontally for some distance and furnishes ascending branches. Their {axons [FMA67308:Axon]}, two or three in number, arise from the {dendrites [FMA67314:Dendrite]}, and, like them, take a horizontal course, giving off numerous ascending collaterals. The distribution of the {axons [FMA67308:Axon]} and {dendrites [FMA67314:Dendrite]} of all three {sets of cells [FMA71954:Set of cells]} is limited to the molecular layer. 157   The Layer of Small and the Layer of Large {Pyramidal Cells [FMA84105:Pyramidal cell of cerebral cortex]}.—The cells in these two layers may be studied together, since, with the exception of the difference in size and the more superficial position of the smaller cells, they resemble each other. The average length of the small cells is from 10 to 15μ; that of the large cells from 20 to 30μ. The body of each cell is {pyramidal [FMA15568:Pyramidalis]} in shape, its base being directed to the deeper parts and its apex toward the surface. It contains granular pigment, and stains deeply with ordinary reagents. The nucleus is of large size, and round or oval in shape. The base of the cell gives off the {axis cylinder [FMA67308:Axon]}, and this runs into the central {white substance [FMA83929:White matter of neuraxis]}, giving off collaterals in its course, and is distributed as a projection, commissural, or association fiber. The apical and {basal parts of the cell [FMA72558:Basal part of cell]} give off {dendrites [FMA67314:Dendrite]}; the apical {dendrite [FMA67314:Dendrite]} is directed toward the surface, and ends in the molecular layer by dividing into numerous branches, all of which may be seen, when prepared by the silver or methylene-blue method, to be studded with projecting bristle-like processes. The largest {pyramidal cells [FMA84105:Pyramidal cell of cerebral cortex]} are found in the upper part of the anterior central gyrus and in the {paracentral lobule [FMA77534:Paracentral lobule]}; they are often arranged in groups or nests of from three to five, and are named the giant cells of Betz. In the former situation they may exceed 50μ in length and 40μ in breadth, while in the {paracentral lobule [FMA77534:Paracentral lobule]} they may attain a length of 65μ. 158   Layer of Polymorphous Cells.—The cells in this layer, as their name implies, are very irregular in contour; they may be fusiform, oval, triangular, or star-shaped. Their {dendrites [FMA67314:Dendrite]} are directed outward, but do not reach so far as the molecular layer; their {axons [FMA67308:Axon]} pass into the subjacent {white matter [FMA83929:White matter of neuraxis]}. 159   There are two other kinds of cells in the {cerebral cortex [FMA61830:Cerebral cortex]}. They are: (a) the cells of Golgi, the {axons [FMA67308:Axon]} of which divide immediately after their origins into a large number of branches, which are directed toward the surface of the {cortex [FMA15632:Adrenal cortex; FMA61109:Cortex]}; (b) the cells of Martinotti, which are chiefly found in the polymorphous layer; their {dendrites [FMA67314:Dendrite]} are short, and may have an ascending or descending course, while their {axons [FMA67308:Axon]} pass out into the molecular layer and form an extensive horizontal arborization.