Journal of the History of the Neurosciences, 24:95–101, 2015 Copyright © Taylor & Francis Group, LLC ISSN: 0964-704X print / 1744-5213 online DOI: 10.1080/0964704X.2014.935654
NEUROwords The Line of Gennari—Sometimes History Gets It Right BARCLAY W. BAKKUM Illinois College of Optometry, Chicago, IL, USA
A commonly used eponymous name in neuroscience is Gennari. The term line (or stripe) of Gennari is used for the stria laminae granularis interna corticis cerebri or stria occipitalis (Terminologia Anatomica, 1998, p. 128). It corresponds to the extra prominent outer line of Baillarger (1840) in the region of the calcarine sulcus (or fissure). This layer of myelinated fibers is visible to the naked eye and is the reason that this portion of the cerebrum is known as the striate cortex. It has been shown that the region where the line of Gennari is visible represents the primary visual cortex and is the main termination site of fibers from the lateral geniculate nucleus of the thalamus that are carrying visual information that originated in the retinas. Historically, many anatomic structures had the name of the person who first described them associated with the name of the structure. In the case of the line of Gennari, for nearly a century, this structure had another name associated with it. Franceso Gennari (1752–1797), a physician in Parma, Italy, published his observations of the superficial and deep structures of the brain in a 1782 monograph titled De Peculiari Structura Cerebri Nonnullisque Eius Morbis (see Figure 1; Fulton, 1937). In it, he described the first observation of the nonuniformity of the human cerebral cortex (see Figure 2): None of the anatomists I have come upon in reading have taught that, besides the cortical substance and the medulla, there exists in the brain another substance which I shall call the third substance of this viscus. If anyone has looked at the horizontal strata of the cortex of the brain dissected at the point where it conjoins with the medulla, he will have found a certain whitish substance (“subalbida”). This does not always present itself in exactly the same spot, appearing a little farther from or a little nearer to the medulla; it is however always observed with the same extension, with the same color, sometimes more abundant and sometimes more obscure; sometimes subtle, sometimes clearer; at points, difficult, at others it is easy to demonstrate. In a defect of a section, especially if it is transected obliquely, this substance disappears; not only in single brains, but also in diverse parts of the same brain I have observed such variations, as if many times it reappeared in such points, afterwards with a duplicate line. Especially in the anterior parts or solely “subobscure,” it is possible to retrace it, but since it becomes denser to the posterior, I have come to Address correspondence to Barclay W. Bakkum, Illinois College of Optometry, 3241 S. Michigan Avenue, Chicago, IL 60616, USA. E-mail: [email protected]
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Figure 1. Title page of Francesco Gennari’s monograph.
the conclusion that its appearance can be more certainly obtained. In the internal part of the posterior lobe of the brain not far from the point in which it extends itself into the tentorium was where the substance of which I am speaking stretched in a line even whiter, but I have not observed it in any other place to be so evident. (trans. in Fulton, 1937, p. 897, emphasis added) It was most prominent in the medial part of the posterior lobe of the brain where he called it the lineola albidior (L. little line, white) (Finger, 1994, p. 79). This discovery was made on sections of an ice-hardened human brain, while he was still a medical student at the University of Parma (Glickstein, 1988). Gennari was apparently unaware of the significance of this discovery:
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Figure 2. Gennari’s drawing showing his “third substance” of the brain in the region of the occipital lobe.
This line I first saw the 2nd of February 1776 and having then often followed it, it seemed to run finally to the ultimate substance of the hippocampus. For the rest I am ignorant to what purpose that substance may be formed, like so many others of which the use is still hidden, at any rate some of those who combat by the animal spirits, may perhaps draw such an argument for their existence, which in every time, even the hour in which I write, is much disputed. I exhort the anatomists in every way to enquire into this substance. (trans. in Gibson, 1962, p. 946) Although he was able to continue his anatomical studies along with his medical practice, Gennari published nothing after this book (Glickstein & Rizzolatti, 1984). This may have been because of personal reasons, since he appears to have been difficult and self-defeating. He died a sad and bitter man. There were two other claimants for the discovery of this structure. One was the famous German anatomist, Samuel Thomas von Sömmerring (1755–1830; see Figure 3) (Hildebrand, 2005). He later claimed to have described the line four years before Gennari. But in his 1778 book, titled De Basi Encephali et Originibus Nervorum Cranio
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Figure 3. Samuel Thomas von Sömmerring (1755–1830).
Egredientium Libri Quinque, that he used to support this claim, Sömmerring described the line he saw in the cerebellum, and not the cerebrum, writing that “One can speak in a certain manner of three cerebellar substances: grey or cortical, medullary (white) and between these a middle substance of a dark yellow colour which arises from the cortex and blends gradually with the white matter” (trans in Glickstein & Rizzolatti, 1984, p. 466). Sömmerring did go on to fully describe the cerebral structure his book Vom Hirn und Rueckenmark in 1788 (Fulton, 1937). The other claimant was the renowned French anatomist Félix Vicq d’Azyr (1748–1794; see Figure 4). He mentioned the line of white matter in the occipital region in a paper titled: Recherches sur la structure du cerveau, du cervelet, de la moelle alongeé, de la moelle épinière; et sur l’origine de nerfs de l’homme et des animaux, which appeared in Histore de L’académie Royale des Science for 1781 (published in 1784; see Fulton, 1937). He wrote that he saw in the posterior lobes a “white linear tract that follows all the contours . . . and gives . . . the appearance of a streaked ribbon” (trans. in Marshall & Magoun, 1998, p. 129). This observation did not get wide acknowledgement until it appeared in Vicq d’Azyr’s monumental textbook, Traité d’Anatomie et
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Figure 4. Félix Vicq d’Azyr (1748–1794). ©Wikipedia. Reproduced by permission of Wikipedia. Permission to reuse must be obtained from the rightsholder.
de Physiologie, published in 1786 (Gijn, 2009). This text included some of the finest sections of the brain or parts of it, colored by means of aquatint, found in neurological literature prior to the 19th century. Each plate was accompanied by an explanatory drawing by Briceau, who was acknowledged by the author. One of these (Plate X) distinctly shows this line restricted to the region of the calcarine fissure (Fulton, 1937). Mostly because of Vicq d’Azyr’s prominence in the scientific community and the relative obscurity of Gennari, this structure was known as the line of Vicq d’Azyr for nearly a century. Heinrich Obersteiner (1847–1922) was a prominent Austrian neurologist who founded the famous Neurological Institute in Vienna (see Figure 5; Seitelberger, 1992). In 1888, Obersteiner apparently compared the dates of Gennari’s and Vicq d’Azyr’s contributions regarding this structure (Glickstein & Rizzolatti, 1984). In his book, Anleitung beim Studium des Baues der nervösen Centralorgane im gesunden und kranken Zustande, he suggested that this structure should be known as the line of Gennari. Maybe because of his fame, Obersteiner’s suggestion received widespread acceptance, and the rest, as they say, is history. Even though Francesco Gennari never published again, died in relative obscurity and did not have his keen observations enjoy general recognition for over a century, he remains
100
Barclay W. Bakkum
Figure 5. Heinrich Obersteiner (1847–1922).
one of the seminal figures in neuroscience, thanks, at least in part, to the historical work of Heinrich Obersteiner. Our lesson from this story may be that history oftentimes gets things right, although not always in a timely enough fashion so that those deserving of the accolades actually are alive to receive them.
References Baillarger JFG (1840): Recherches sur la structure de la couche corticale des circonvolutions du cerveau. Mémoires de l’Académie de Médecine de Paris 8: 149–183. Finger S (1994): Origins of Neuroscience: A History of Explorations into Brain Function. New York, Oxford University Press. Fulton JF (1937): A note on Francesco Gennari and the early history of the cytoarchitectural studies of the cerebral cortex. Bulletin of the History of Medicine 5: 895–913. Gennari F (1782): De Peculiari Structura Cerebri Nonnullisque Eius Morbis. Parma, Ex Regio Typographeo. Gibson WC (1962): Pioneers in localization of function in the brain. Journal of the American Medical Association 180: 944–951. Gijn J van (2009): Félix Vicq d’Azyr (1748–1794). Journal of Neurology 256: 1384–1385. Glickstein M (1988): The discovery of the visual cortex. Scientific American 259: 118–127. Glickstein M, Rizzolatti G (1984): Francesco Gennari and the structure of the cerebral cortex. Trends in Neurosciences 7: 464–467.
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Hildebrand R (2005): Soemmerring’s work on the nervous system: A view on brain structure and function from the late eighteenth century. Anatomy and Embryology 210: 337–342. Marshall LH, Magoun HW (1998): Discoveries in the Human Brain. Totowa, NJ, Humana Press. Obersteiner H (1888): Anleitung beim Studium des Baues der nervösen Centralorgane im gesunden und kranken Zustande. Leipzig, Toeplitz & Deutlicke. Seitelberger F (1992): Heinrich Obersteiner and the Neurologic Institute: Foundation and history of neuroscience in Vienna. Brain Pathology 2: 163–168. Sömmerring ST (1778): De Basi Encephali et Originibus Nervorum Cranio Egredientium Libri Quinque. Göttingen, Vandenhoek Widow. Sömmerring ST (1788): Vom Hirn und Rueckenmark. Mainz, P. A. Winkopp. Terminologia Anatomica (1998): International Anatomical Terminology. Stuttgart, New York, Thieme. Vicq d’Azyr F (1784): Recherches sur la structure du cerveau, du cervelet, de la moelle alongeé, de la moelle épinière; et sur l’origine de nerfs de l’homme et des animaux. Histore de l’Académie Royale des Science: 495–622. Vicq d’Azyr F (1786): Traité d’Anatomie et de Physiologie. Paris, F. A. Didot
Copyright of Journal of the History of the Neurosciences is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
NEUROwords The Line of Gennari—Sometimes History Gets It Right BARCLAY W. BAKKUM Illinois College of Optometry, Chicago, IL, USA
A commonly used eponymous name in neuroscience is Gennari. The term line (or stripe) of Gennari is used for the stria laminae granularis interna corticis cerebri or stria occipitalis (Terminologia Anatomica, 1998, p. 128). It corresponds to the extra prominent outer line of Baillarger (1840) in the region of the calcarine sulcus (or fissure). This layer of myelinated fibers is visible to the naked eye and is the reason that this portion of the cerebrum is known as the striate cortex. It has been shown that the region where the line of Gennari is visible represents the primary visual cortex and is the main termination site of fibers from the lateral geniculate nucleus of the thalamus that are carrying visual information that originated in the retinas. Historically, many anatomic structures had the name of the person who first described them associated with the name of the structure. In the case of the line of Gennari, for nearly a century, this structure had another name associated with it. Franceso Gennari (1752–1797), a physician in Parma, Italy, published his observations of the superficial and deep structures of the brain in a 1782 monograph titled De Peculiari Structura Cerebri Nonnullisque Eius Morbis (see Figure 1; Fulton, 1937). In it, he described the first observation of the nonuniformity of the human cerebral cortex (see Figure 2): None of the anatomists I have come upon in reading have taught that, besides the cortical substance and the medulla, there exists in the brain another substance which I shall call the third substance of this viscus. If anyone has looked at the horizontal strata of the cortex of the brain dissected at the point where it conjoins with the medulla, he will have found a certain whitish substance (“subalbida”). This does not always present itself in exactly the same spot, appearing a little farther from or a little nearer to the medulla; it is however always observed with the same extension, with the same color, sometimes more abundant and sometimes more obscure; sometimes subtle, sometimes clearer; at points, difficult, at others it is easy to demonstrate. In a defect of a section, especially if it is transected obliquely, this substance disappears; not only in single brains, but also in diverse parts of the same brain I have observed such variations, as if many times it reappeared in such points, afterwards with a duplicate line. Especially in the anterior parts or solely “subobscure,” it is possible to retrace it, but since it becomes denser to the posterior, I have come to Address correspondence to Barclay W. Bakkum, Illinois College of Optometry, 3241 S. Michigan Avenue, Chicago, IL 60616, USA. E-mail: [email protected]
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Barclay W. Bakkum
Figure 1. Title page of Francesco Gennari’s monograph.
the conclusion that its appearance can be more certainly obtained. In the internal part of the posterior lobe of the brain not far from the point in which it extends itself into the tentorium was where the substance of which I am speaking stretched in a line even whiter, but I have not observed it in any other place to be so evident. (trans. in Fulton, 1937, p. 897, emphasis added) It was most prominent in the medial part of the posterior lobe of the brain where he called it the lineola albidior (L. little line, white) (Finger, 1994, p. 79). This discovery was made on sections of an ice-hardened human brain, while he was still a medical student at the University of Parma (Glickstein, 1988). Gennari was apparently unaware of the significance of this discovery:
NEUROwords
97
Figure 2. Gennari’s drawing showing his “third substance” of the brain in the region of the occipital lobe.
This line I first saw the 2nd of February 1776 and having then often followed it, it seemed to run finally to the ultimate substance of the hippocampus. For the rest I am ignorant to what purpose that substance may be formed, like so many others of which the use is still hidden, at any rate some of those who combat by the animal spirits, may perhaps draw such an argument for their existence, which in every time, even the hour in which I write, is much disputed. I exhort the anatomists in every way to enquire into this substance. (trans. in Gibson, 1962, p. 946) Although he was able to continue his anatomical studies along with his medical practice, Gennari published nothing after this book (Glickstein & Rizzolatti, 1984). This may have been because of personal reasons, since he appears to have been difficult and self-defeating. He died a sad and bitter man. There were two other claimants for the discovery of this structure. One was the famous German anatomist, Samuel Thomas von Sömmerring (1755–1830; see Figure 3) (Hildebrand, 2005). He later claimed to have described the line four years before Gennari. But in his 1778 book, titled De Basi Encephali et Originibus Nervorum Cranio
98
Barclay W. Bakkum
Figure 3. Samuel Thomas von Sömmerring (1755–1830).
Egredientium Libri Quinque, that he used to support this claim, Sömmerring described the line he saw in the cerebellum, and not the cerebrum, writing that “One can speak in a certain manner of three cerebellar substances: grey or cortical, medullary (white) and between these a middle substance of a dark yellow colour which arises from the cortex and blends gradually with the white matter” (trans in Glickstein & Rizzolatti, 1984, p. 466). Sömmerring did go on to fully describe the cerebral structure his book Vom Hirn und Rueckenmark in 1788 (Fulton, 1937). The other claimant was the renowned French anatomist Félix Vicq d’Azyr (1748–1794; see Figure 4). He mentioned the line of white matter in the occipital region in a paper titled: Recherches sur la structure du cerveau, du cervelet, de la moelle alongeé, de la moelle épinière; et sur l’origine de nerfs de l’homme et des animaux, which appeared in Histore de L’académie Royale des Science for 1781 (published in 1784; see Fulton, 1937). He wrote that he saw in the posterior lobes a “white linear tract that follows all the contours . . . and gives . . . the appearance of a streaked ribbon” (trans. in Marshall & Magoun, 1998, p. 129). This observation did not get wide acknowledgement until it appeared in Vicq d’Azyr’s monumental textbook, Traité d’Anatomie et
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99
Figure 4. Félix Vicq d’Azyr (1748–1794). ©Wikipedia. Reproduced by permission of Wikipedia. Permission to reuse must be obtained from the rightsholder.
de Physiologie, published in 1786 (Gijn, 2009). This text included some of the finest sections of the brain or parts of it, colored by means of aquatint, found in neurological literature prior to the 19th century. Each plate was accompanied by an explanatory drawing by Briceau, who was acknowledged by the author. One of these (Plate X) distinctly shows this line restricted to the region of the calcarine fissure (Fulton, 1937). Mostly because of Vicq d’Azyr’s prominence in the scientific community and the relative obscurity of Gennari, this structure was known as the line of Vicq d’Azyr for nearly a century. Heinrich Obersteiner (1847–1922) was a prominent Austrian neurologist who founded the famous Neurological Institute in Vienna (see Figure 5; Seitelberger, 1992). In 1888, Obersteiner apparently compared the dates of Gennari’s and Vicq d’Azyr’s contributions regarding this structure (Glickstein & Rizzolatti, 1984). In his book, Anleitung beim Studium des Baues der nervösen Centralorgane im gesunden und kranken Zustande, he suggested that this structure should be known as the line of Gennari. Maybe because of his fame, Obersteiner’s suggestion received widespread acceptance, and the rest, as they say, is history. Even though Francesco Gennari never published again, died in relative obscurity and did not have his keen observations enjoy general recognition for over a century, he remains
100
Barclay W. Bakkum
Figure 5. Heinrich Obersteiner (1847–1922).
one of the seminal figures in neuroscience, thanks, at least in part, to the historical work of Heinrich Obersteiner. Our lesson from this story may be that history oftentimes gets things right, although not always in a timely enough fashion so that those deserving of the accolades actually are alive to receive them.
References Baillarger JFG (1840): Recherches sur la structure de la couche corticale des circonvolutions du cerveau. Mémoires de l’Académie de Médecine de Paris 8: 149–183. Finger S (1994): Origins of Neuroscience: A History of Explorations into Brain Function. New York, Oxford University Press. Fulton JF (1937): A note on Francesco Gennari and the early history of the cytoarchitectural studies of the cerebral cortex. Bulletin of the History of Medicine 5: 895–913. Gennari F (1782): De Peculiari Structura Cerebri Nonnullisque Eius Morbis. Parma, Ex Regio Typographeo. Gibson WC (1962): Pioneers in localization of function in the brain. Journal of the American Medical Association 180: 944–951. Gijn J van (2009): Félix Vicq d’Azyr (1748–1794). Journal of Neurology 256: 1384–1385. Glickstein M (1988): The discovery of the visual cortex. Scientific American 259: 118–127. Glickstein M, Rizzolatti G (1984): Francesco Gennari and the structure of the cerebral cortex. Trends in Neurosciences 7: 464–467.
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Hildebrand R (2005): Soemmerring’s work on the nervous system: A view on brain structure and function from the late eighteenth century. Anatomy and Embryology 210: 337–342. Marshall LH, Magoun HW (1998): Discoveries in the Human Brain. Totowa, NJ, Humana Press. Obersteiner H (1888): Anleitung beim Studium des Baues der nervösen Centralorgane im gesunden und kranken Zustande. Leipzig, Toeplitz & Deutlicke. Seitelberger F (1992): Heinrich Obersteiner and the Neurologic Institute: Foundation and history of neuroscience in Vienna. Brain Pathology 2: 163–168. Sömmerring ST (1778): De Basi Encephali et Originibus Nervorum Cranio Egredientium Libri Quinque. Göttingen, Vandenhoek Widow. Sömmerring ST (1788): Vom Hirn und Rueckenmark. Mainz, P. A. Winkopp. Terminologia Anatomica (1998): International Anatomical Terminology. Stuttgart, New York, Thieme. Vicq d’Azyr F (1784): Recherches sur la structure du cerveau, du cervelet, de la moelle alongeé, de la moelle épinière; et sur l’origine de nerfs de l’homme et des animaux. Histore de l’Académie Royale des Science: 495–622. Vicq d’Azyr F (1786): Traité d’Anatomie et de Physiologie. Paris, F. A. Didot
Copyright of Journal of the History of the Neurosciences is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
