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In August 1908, a white mob attacked Springfield, Illinois’s Black community, destroying homes and businesses and lynching two Black men. National outrage over the violence helped spur the movement that created the NAACP the following year.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
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| Brodmann area 4 | |
|---|---|
 Brodmann area 4 (orange) | |
 Brodmann area 4 of human brain. | |
| Details | |
| Part of | Precentral gyrus |
| Identifiers | |
| Latin | area gigantopyramidalis |
| NeuroNames | 2394, 1014 |
| NeuroLex ID | birnlex_1735 |
| FMA | 68600 |
| Anatomical terms of neuroanatomy | |
Brodmann area 4 refers to the primary motor cortex of the human brain, one of the Brodmann areas. It is located in the posterior portion of the frontal lobe.
Brodmann area 4 is part of the precentral gyrus. The borders of this area are: the precentral sulcus in front (anteriorly), the medial longitudinal fissure at the top (medially), the central sulcus in back (posteriorly), and the lateral sulcus along the bottom (laterally).
This area of cortex, as shown by Wilder Penfield and others, has the pattern of a homunculus. That is, the legs and trunk fold over the midline; the arms and hands are along the middle of the area shown here; and the face is near the bottom of the figure. Because Brodmann area 4 is in the same general location as primary motor cortex, the homunculus here is called the motor homunculus.
The term area 4 of Brodmann-1909 refers to a cytoarchitecturally defined portion of the frontal lobe of the guenon. It is located predominantly in the precentral gyrus. Brodmann-1909 regarded it as topographically and cytoarchitecturally homologous to the human gigantopyramidal area 4 and noted that it occupies a much greater fraction of the frontal lobe in the monkey than in the human.
Distinctive features (Brodmann-1905): the cortex is unusually thick; the layers are not distinct; the cells are relatively sparsely distributed; giant pyramidal (Betz) cells are present in the internal pyramidal layer (V); lack of an internal granular layer (IV) such that the boundary between the external pyramidal layer (III) and the internal pyramidal layer (V) is indistinct; lack of a distinct external granular layer (II); a gradual transition from the multiform layer (VI) to the subcortical white matter.[1]
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
Brodmann area 4 refers to the primary motor cortex of the human brain, one of the Brodmann areas. It is located in the posterior portion of the frontal lobe. Brodmann area 4 is part of the precentral gyrus. The borders of this area are: the precentral sulcus in front (anteriorly), the medial longitudinal fissure at the top (medially), the central sulcus in back (posteriorly), and the lateral sulcus along the bottom (laterally). This area of cortex, as shown by Wilder Penfield and others, has the pattern of a homunculus. That is, the legs and trunk fold over the midline; the arms and hands are along the middle of the area shown here; and the face is near the bottom of the figure. Because Brodmann area 4 is in the same general location as primary motor cortex, the homunculus here is called the motor homunculus. The term area 4 of Brodmann-1909 refers to a cytoarchitecturally defined portion of the frontal lobe of the guenon. It is located predominantly in the precentral gyrus. Brodmann-1909 regarded it as topographically and cytoarchitecturally homologous to the human gigantopyramidal area 4 and noted that it occupies a much greater fraction of the frontal lobe in the monkey than in the human. Distinctive features (Brodmann-1905): the cortex is unusually thick; the layers are not distinct; the cells are relatively sparsely distributed; giant pyramidal (Betz) cells are present in the internal pyramidal layer (V); lack of an internal granular layer (IV) such that the boundary between the external pyramidal layer (III) and the internal pyramidal layer (V) is indistinct; lack of a distinct external granular layer (II); a gradual transition from the multiform layer (VI) to the subcortical white matter.
Brodmann area 12 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It occupies the most rostral portion of the frontal lobe. Brodmann-1909 did not regard it as homologous, either topographically or cytoarchitecturally, to rostral area 12 of the human. Distinctive features (Brodmann-1905): a quite distinct internal granular layer (IV) separates slender pyramidal cells of the external pyramidal layer (III) and the internal pyramidal layer (V); the multiform layer (VI) is expanded, contains widely dispersed spindle cells and merges gradually with the underlying cortical white matter; all cells, including the pyramidal cells of the external and internal pyramidal layers are inordinately small; the internal pyramidal layer (V) also contains spindle cells in groups of two to five located close to its border with the internal granular layer (IV). It is indirectly connected to the globus pallidus as well as the substantia nigra, due to efferents to the striatum. Glutaminergic input is turned into GABAergic input there, which allows the frontal lobes to exhibit some control over basal ganglia activity.
The bands of Baillarger, in neuroanatomy, are two myeloarchitectural structures, the external band of Baillarger and the internal band of Baillarger. These are myelinated fibers that course in the internal granular layer (layer IV) and internal pyramidal layer (layer V), respectively, of cerebral cortex. In the primary visual cortex (V1), the external band of Baillarger is enlarged and is called the line of Gennari. They are named after Jules Baillarger.
Cartwheel cells are neurons of the dorsal cochlear nucleus (DCN) where they greatly outnumber the other inhibitory interneurons of the DCN. Their somas lie on the superficial side of the pyramidal layer of the DCN, and their dendrites receive input from the parallel fibres of the granule cell layer. Their axons do not extend beyond the dorsal cochlear nucleus but synapse with other cartwheel cells and pyramidal cells within the DCN releasing GABA and glycine onto their targets. Cartwheel cells have similar spiking patterns to Purkinje cells, firing complex spike bursts as well as simple spikes. They are also seen to share other features common to the cerebellar Purkinje cells. Other data supports the structural and functional similarity found between the cartwheel and the Purkinje neuron. Cartwheel cells are shown to have a high density of spines on their dendrites, their axons are myelinated, they are of spherical cell shape and of medium size. The primary targets of the cartwheel cells are the large efferent pyramidal neurons of the DCN, found in layer two. Data retrieved has shown that this targeting of the pyramidal cells modulates their activity and therefore plays a key role in the shaping of the overall output of the superficial layers of the dorsal cochlear nucleus.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →The Greenwood District.