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Published in Anton Sebastian, A Dictionary of the History of Medicine, 2018
Cerebral Cortex [Latin: cerebrum, brain + cortex, bark] The structural organization was observed in 1776 by an Italian anatomist Francesco Gennari (1750–1797) of Parma, while he was a medical student. He also made a special note of the white line in the cortex which was most prominent in the occipital area. This was identified as the primary visual cortex and named the ‘Line of Gennari’. In 1840, the French psychiatrist Jules Gabriel François Baillarger (1809–1890) noted that these lines consisted of two bands separated by a thin dark line. They were traced throughout the cortex and named’internal and external bands of Baillarger’.Theodore Herman Meynert (1833–1892) of Vienna systematically studied cortical cells and identified five horizontal layers in 1867. Knowledge on the different layers of the cortex was advanced by Russian neurologist, Vladimir Aleksandrovich Betz (1834–1894) in 1874, and by an English neuropsychiatrist, William Bevan Lewis (1847–1929) in 1878.The Italian neurologist Camillo Golgi (1844–1926) of Pavia discovered in 1886 that the cells with short axons ramified in the cortex. Elliot Smith (1871–1937) in 1907 divided the brain into 50 zones on the basis of Baillarger bands. See brain, motor cortex, architronics.
Specific Synonyms
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Line of Gennari (B&K, p. 225) Line of Vicq d’Azyr (Brod, p. 793)Stria of Gennari (Gar, p. 142)Visual stria (W&W, p. 1018)
Patty
Published in Walter J. Hendelman, Peter Humphreys, Christopher R. Skinner, The Integrated Nervous System, 2017
Walter J. Hendelman, Peter Humphreys, Christopher R. Skinner
The prominence or thickness of each of the six cortical layers varies from one cortical region to another, depending upon the primary function of that region. For example, in the primary motor cortex of the precentral gyrus, layer 5 – containing the greatest concentration of motor neurons – is unusually thick. In contrast, the primary visual cortex adjacent to the calcarine fissure has a prominent layer 4, the termination point of the optic radiations; indeed, this layer of the visual cortex contains so many myelinated nerve fibers that it appears as a white band within the cortex of the post-mortem brain. This so-called line of Gennari is the reason the primary visual cortex is sometimes referred to as striate cortex.
The perversion of language: Jules Baillarger on aphasia, the lateralization of speech, and the Baillarger-Jackson principle
Published in Journal of the History of the Neurosciences, 2021
Broca undoubtedly got this notion from Baillarger, who had observed variations in the thickness of individual layers of the cortex in his 1840 treatise: Without insisting on all the variations that can occur in the organization of the cortical layer, I will highlight a few. … It often happens that the two intermediate white laminae are very close to each other so that the grey matter between them is thinned or may not be discernable. … Sometimes the two white laminae are very close to the cortical white matter and the grey matter is almost absent … [and] the first four layers then appear as a single thick layer. … The white line described by Vicq-d’Azyr34This is also known as the line of Gennari or the external band of Baillarger, which is notably prominent in the calcarine cortex. which divides the grey matter of the posterior [occipital] lobe is very noticeable and appears as one. (Baillarger 1840, 153)
White matter—Maximien Parchappe and the integration of articulate language
Published in Journal of the History of the Neurosciences, 2020
Parchappe considered that the cortex was composed of two layers,7Parchappe performed his examinations of the brains before Jules Baillarger’s discovery that the cerebral cortex is composed of six alternating gray and white matter layers (Baillarger 1840). distinguishable by different shades of gray, with the exception of the occipital cortex, which had an interposed layer of white matter.8The line of Gennari or the white line of Vicq d’Azyr. He found that 44 of the 131 patients who had come to autopsy fit the diagnostic criteria of GPI, and that 43 had extensive softening (ramollissement)9Softening (ramollissement) was a descriptive term used at the time to indicate the tactile impression one felt when palpating the damaged brain at autopsy. The term was most often used in reference to a vascular injury, but softening could result from a number of pathologies. of the middle aspect of the cortex at the junction of the two cortical layers. In some cases, the softening extended to the outer layer, and in a few cases, the whole of the cortex was softened. These pathognomonic changes were most frequent in the anterior aspect of the brain, and most notably in the frontal lobes. The pia-arachnoid was adherent to the superficial cortical layer, as Bayle had observed (Parchappe 1838, 165–169), but Parchappe considered this to be secondary to the primary pathology affecting the cortex.