A Hole in the Head

by Charles G Gross

  21. Lewis, 1877.

  22. Bernard, 1961, 1974; Virtanen, 1960; Fredericq, 1973; Petit, 1987.

  23. Holmes, 1965.

  24. Holmes, 1965; Fredericq, 1973.

  25. Holmes, 1965; Macallum, 1926.

  26. Starling, 1909.

  27. Barcroft, 1932.

  28. Haldane, 1931.

  29. Sherringon, 1961.

  30. Henderson, 1928.

  31. Henderson, 1958, 1961

  32. Cannon, 1929.

  33. Cannon, 1963.

  34. Watson, 1924; Richter, 1927; Cannon, 1963.

  35. Cannon, 1963; Henderson, 1935.

  36. Rosenblueth et al., 1943.

  37. Wiener, 1961.

  38. Gardner, 1985.

  39. Virtanen, 1960; Olmsted, 1967; Petit, 1987.

  40. Gross, 1997a.

  9

  BARTOLOMEO PANIZZA AND THE VISUAL BRAIN WITH MICHAEL COLOMBO AND ARNALDO COLOMBO

  Bartolomeo Panizza (1785–1867) was the first person to produce experimental and clinicopathological evidence for a visual area in the posterior cerebral cortex. This was, arguably, the first systematic evidence for the localization of function in the cerebral cortex. We here provide the first translation of this work entitled “Observations on the optic nerve,” originally published in Italian in 1855. Published before Broca’s and Fritsch and Hitzig’s work,1 which are usually considered to have initiated cerebral localization, Panizza’s discovery of visual cortex was ignored until after its independent rediscovery. It was then largely forgotten. In this article we briefly review the knowledge of the brain in Panizza’s time, summarize his scientific career, consider why his paper on visual cortex was lost, and then provide the first full translation of this paper originally published in 1855.2

  THE CEREBRAL CORTEX IN 1855

  The first half of the nineteenth century was a period of conflicting views on the functions of the cerebral cortex.3 In the eighteenth century, the standard view of the brain was that of Albrecht von Haller (1708–1777), a Swiss naturalist, anatomist, and physiologist and the dominant figure in brain anatomy and physiology. He believed that all parts of the brain had the same organization and functioned in the same way. This unity of the brain, he thought, reflected the unity of the soul. This view was challenged at the beginning of the nineteenth century by Franz Joseph Gall and Johann Gaspard Spurzheim: their phrenological system postulated that the cerebral cortex was a set of organs with different psychological functions (see chapter 4 and figures 4.5 and 4.6). These 27 organs were concerned with “affective” or “intellectual” faculties; basic sensory and motor functions were thought to be subcortical, residing in the thalamus and corpus striatum, respectively.4

  Gall’s theories of punctate localization in the cortex were attacked by Pierre Flourens (1794–1867). He reported that lesions of the cerebral cortex had devastating effects on willing, judging, remembering, and perceiving, but that the site of the cortical lesion did not matter. However, lesions to other structures such as the cerebellum and the medulla did produce different symptoms. Flourens’s findings, although a refutation of Gall’s methods and specific localizations, were actually a confirmation of Gall’s general attempt to localize functions in different parts of the brain and of his emphasis on the higher roles of the cerebral cortex.5

  Although Gall and Spurzheim’s use of cranial morphology (“bumps”) was soon rejected by the scientific community, Gall’s ideas of punctate localization spurred the search for different cortical organs. For example, Jean-Baptiste Bouillaud (1796–1881) tried to support some of Gall’s localizations, such as of language, by direct clinicopathological examination of human patients. Two major discoveries finally established the idea of localization of function in the cerebral cortex. The first was Broca’s report of a relationship between damage to the left frontal lobe and deficits in speaking.6 The second was Fritsch and Hitzig’s demonstration of specific movements from electrical stimulation of specific regions of the cortex.7 At the time both these discoveries were viewed as vindication of Gall’s ideas of the localization of function in the cortex.8 Both occurred after Panizza’s article, here translated, was published. (See chapter 4.)

  WHO WAS BARTOLOMEO PANIZZA?

  Panizza was born in Vicenza, Italy, and took his degree in surgery at the University of Padua in 1806 and in medicine at the University of Pavia in 1810. With the help of his father, a distinguished physician, he chose an academic research career rather than going into medical practice. Panizza became professor of anatomy at Pavia at the early age of 32 and held this position for the next 50 years. He appears to have “enjoyed the very highest reputation among Italian and foreign scientists”9 and received a number of awards and honors for his research as well as appointments as dean of the medical faculty and rector of the University of Pavia. Panizza worked on a variety of subjects including the lymphatic and circulatory systems, the parotid gland, and the cranial nerves. His last major paper was the one here translated, published when he was 70.10

  THE ACHIEVEMENTS OF “OBSERVATIONS ON THE OPTIC NERVE”

  This study utilized a wide range of species from fish to humans, and two main techniques. The first technique was to unilaterally blind animals (enucleation) and then trace the resultant degeneration. This method, known as the “atrophic degeneration method,” was later rediscovered and credited to von Gudden (1824–1889).11 Panizza found it worked particularly well when the enucleation was done in infancy and the anatomy in adulthood. Using this method he inferred that, in mammals, parts of the thalamus and the posterior cerebral cortex were visual in function. The second principal method that Panizza used was to make lesions and observe the resultant behavior. When he made lesions in the brain regions in which he had found degeneration after enucleation, he found the animals to be blind contralateral to the lesion. Thus, in mammals, after lesions of the thalamus or the posterior cortex he observed contralateral blindness, confirming his idea that these were visual structures (and that the decussation of the optic pathways was total in mammals as well as other animals). He further supported this interpretation by observations of pathology in the thalamus and posterior cortex in two human patients who, he thought, were blind contralateral to the lesion. It is very likely that Panizza interpreted his results as supporting Gall’s view that “the brain [is] a complex of organs” but added that “it is not easy to determine their number, the seat of each one, and their respective functions.”

  WHY WAS PANIZZA’S PAPER ON THE VISUAL SYSTEM IGNORED?

  Panizza’s work on the visual areas of the brain does not seem to have been cited in the scientific literature until after the report of Munk in 1878 of a visual area in the occipital cortex of the dog. Luciani and Tamburini repeated Munk’s observations,12 and Tamburini subsequently cited Panizza’s work for the first time.13 Subsequently, Panizza’s work has usually been ignored in discussion of the history of localization of function, although both Finger and Polyak mention him, and there has been a recent surge of interest in him by his countrymen.14 Why was Panizza’s paper ignored at the time, particularly since he was an established scientist and the subject of localization of function was one of much interest at the time? One reason may have been because it was in Italian and in a local publication. However, such publications were normally exchanged with the Royal Society and other scientific societies. Another reason may have been because at this time the general view, in fact the view of both Gall and Flourens, was that the cerebral cortex was devoted to higher “psychic” functions and subcortical regions were the highest centers for vision and other senses. Panizza’s work seems yet another example of a work being too “ahead of its time” to be grasped by its contemporaries.

  ON THE TRANSLATION

  “Observations on the optic nerve” was originally delivered as a speech on April 19, 1855, to the Lombardy Institute of Science,15 and published later that year.16 Throughout the manuscript we have placed the modern-day names of anatomical structures in brackets.<
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  TRANSLATION OF PANIZZA’S 1855 “OBSERVATIONS ON THE OPTIC NERVE”

  The object of science is truth, of art beauty

  —Giordani

  Although many famous anatomists have conducted serious and important studies on the origins of the optic nerve, and have ascertained, especially with the assistance of embryology and live dissection, that the principle origin of this nerve is the bigeminal eminence17 [optic tectum in fish or superior colliculus in mammals], they are no longer in agreement over the parts that are contributed by the optic thalamus, the cerebral peduncles, the tuber cinereum, the lateral walls of the infundibulum of the third ventricle, etc. For the purpose of clarifying the true relationship of the optic nerve with the brain I believe that it was worthwhile for me to also look into this.

  In fish (a class of animal in which the brain is very different from one genus to the other) I examined only the brains of river fish, especially that of Exos lucius [pike] and Cyprinus tinca [tench], of which I wanted to determine the external and internal parts.

  In pike the tubercles or anterior lobes [telencephalon], that some call the cerebral hemispheres (Table VIII [reproduced here in figure 9.1], Figure 1b), of conical form, knobby, and ash-colored are divided in two masses by a barely visible almost transverse but deep sulcus; the small anterior mass that forms the apex of the cone belongs to the olfactory nerve; the other bigger mass covers a part of the first one and is on top of it and attached with a part of its substance at the root of the olfactory nerve, so that it is part of the same and joins the hollow lobe18 [optic tectum] located posteriorly. The hollow lobes (Figure 1d) are big, oval, and tinted ash-white; between their anterior extremities and the anterior lobes some anatomists have noted a small ash-colored mass that they call the pineal body. In my examination of various pike brains I did not see this body; instead I noticed, pulling back a bit the anterior extremities of the hollow lobes, two ash-colored small tubercles (Figure 1c), at times just visible, one to the right, the other to the left, that became white, and converging unite at the medial line (Table VIII, Figure 6a). When the hollow lobes are opened, we can see that their walls are comprised of three layers, an external fibrous-white layer, a middle ash-colored layer, and an interior layer that is medullary and fibrous.19 In the inferior part of the interior layer there are some fibrous fascia, white, composed of many slender fibers (Figure 6d) that disperse like a fan on the sides and roof of the cavity. These lamina radiate anteriorly, folding with some fibers which, close to the medial line, join with those from the other lobe, thus forming a medullary commissure. The ash-colored body on top of the base of the radiating fibers, and called the corpus striatum or optic thalamus20 (Figure 6c), does not converge to form the aforementioned fibers. In the common cavity of the hollow lobes at the medial posterior part one can discern a ridge formed by four eminences, similar in their disposition and configuration to the quadrigeminal eminence21 (Figure 6e), but they are only bends of the ash-colored medullary lamina of the hollow lobes (Figure 7a). The small brain [cerebellum] that is situated posteriorly of the aforementioned hollow lobes, has a conical form, and with its margins is united at the lateral eminence of the elongated medulla [medulla oblongata]. The substance of the small brain is very reddish, is rich in vessels, and has at its core a fibrous mass. On the external surface inferior to the brain are two lobes called the inferior lobes, oval-shaped or kidney-shaped, that some consider the mammillary eminence (Figure 2c). These lobes, however, located beside the inferior branch of the optic nerve, do not supply fibers to it.

  Figure 9.1

  Panizza’s Table VIII. The figures on the first line represent the brain of the pike shown in various positions and sections. Figure 1. Superior surface of the brain: (a) optic nerve, (b) anterior lobe, (c) small tubercle, (d) hollow lobe, and (e) small brain. Figure 2. Inferior surface of the brain: (a) decussation of the optic nerves, (b) pituitary body, (c) inferior lobes of the brain, and (d) elongated medulla. Figure 3. Side view of the brain. Figure 4. Inferior surface of the brain after removal of the superimposed optic nerves: (a) arcuate columns. Figure 5. Superior surface of the brain with removal of the hollow lobes to show the commissure, the superior internal upper roots of optic nerves, and the two small tubercles: (a) commissures, and (b) the meeting of two nerve fascia which comprise the optic nerve or hollow lobe. Figure 6. Shows the two small tubercles and the internal parts of hollow lobes: (a) small tubercles, (b) walls of the hollow lobe, (c) corpus striatum, (d) radiating lamina, and (e) quadrigeminal eminence. Figure 7. Side view of the vertical section of the brain: (a) shows that the quadrigeminal eminence are just the refoldings of the walls of the hollow lobes. Brain of tench (Figures 8–14 represent the brain of the tench in various positions.) Figure 8. Superior surface of the brain: (a) anterior lobes, (b) hollow lobes, (c) small brain, (d) appendix of the small brain, and (e) leg of the small brain. Figure 9. Brain shown from the inferior surface: (a) crossing of optic nerves, (b) pituitary body, (c) inferior and reniform lobe, (d) hollow lobe, and (e) elongated medulla. Figure 10. Side view of the brain. Figure 11. Shifting of the two hollow lobes to show the upper roots of the optic nerves and the fibrous apparatus positioned between them. Figure 12. Section of the hollow lobes and the objects contained therein: (a) contour of the section, and (b) internal eminence that almost entirely fills the cavity. Figure 13. Shows the parts of the hollow lobe located under the internal eminence: (a) corpus striatum, and (b) small body that is part of the optic nerve. Figure 14. Side view of the vertical section of brain. Figure 15. Brain of a tench that was blinded in the right eye when it was young, and dissected after 1 year: (a) atrophy of left anterior lobe, (b) atrophy of hollow lobe, and (c) atrophy of the nerve of the right eye. Figure 16. Another similar example: (a) developed eye and optic nerve, (b) developed right anterior lobe, and (c) hollow lobe and pronounced objects contained therein, while there is atrophy of the right eye, its nerve, and left anterior lobe and hollow lobe. Figure 17. Another example of a tench that when young was blinded in one eye, showing the alterations that occurred in the objects contained in the hollow lobe: (a) atrophy of the hollow lobe in which the internal objects were also atrophied, and (b) well-developed right hollow lobe containing the corpus striatum, the internal lobe, and the other small tubercle likewise developed. Figure 18. Brain of a chicken: (a) cerebral hemisphere, (b) olfactory lobe, (c) optic nerve, and (d) optic lobe. Figure 19. Removal of the two cerebral hemispheres to demonstrate the radiating lamina of the flat surface of the cerebral hemispheres: (a) the neural peduncle of the radiating lamina that joins the optic nerve before arriving at the aja, the other part turns inside the foot of the brain and terminates at the anterior apex of the optic thalamus. Figure 20. Head of a chicken blinded in the left eye as a chick; after 8 months the skull was opened and an increase in the left side and a depression on the right side was found. Figure 21. Brain of the same chicken; the left brain hemisphere is larger and protruding on the posterior superior part. Figure 22. The same shown from the inferior surface: (a) the left hemisphere is more developed, and (b) the optic lobe is bigger, as is the nerve, while the opposite optic lobe and nerve are atrophied. Figure 23. Brain of a duck. Figure 24. Head of a duck that was blinded in the left eye a few days after birth; after a few months the eye was atrophied, the orbit was smaller. The right eye is well developed, the skull in the left superior posterior part is larger, and on the right side it is depressed. Figure 25: (a) More developed left hemisphere. Figure 26. Inferior surface of the same brain that shows a larger left hemisphere: (a) of the optic lobe and corresponding nerve, and (b) atrophy of the right optic lobe and nerve.

  For the nerves I examined only the optic nerves in their passage from the eye to the brain. When one nerve meets the other it passes over it; sometimes the nerve on the right crosses over the nerve on the left; or sometimes the opposite happens, however, they never join, remaining attached only by a cellular fabric. Behind this intersection they are joined by the fibers from the tuber cinereum
, at which point each nerve is divided into two fascia, a superior slender one that runs back along the superior internal side of the hollow lobe, the other, thicker, that wraps along the inferior internal side of this same lobe. Between the two inferior fibrous fascia before the peduncle of the pituitary gland, one finds the medullary lamina of Haller, that joins these two fascia, and behind this are two medullary fibrous arches one anterior, the other posterior, that convexes anteriorly (Figure 4a): these arches are connected to the interior fibers of the inferior optic fascia.

  The brain of the Cyprinus tinca, both in its external contour and in its internal parts, differs significantly from the previous description. The anterior lobes, referred to by some as the cerebral hemispheres, are more conical in shape; the hollow lobes have a rounder shape than those of the pike. The two lateral eminences of the elongated medulla are more arched and protruding; furthermore, behind the small brain, along the medial line of the fourth ventricle, there is a very notable cerebral appendix. The hollow lobes, unlike those of Exos lucius, internally have an eminence that almost fills the cavity (Table VIII, Figure 12b); the eminence is unattached in all its contours except at its inferior part where it is attached to the floor of the cavity. Removal of this eminence reveals another small eminence, referred to by some as the optic thalamus or corpus striatum (Figure 13a), under which one can find another very small projecting body that is directly connected to the inferior branch of the optic nerve (Table VIII, Figure 13b).

  The relationship of the optic nerve of the tench to the hollow lobes and other structures is no different from that of the pike.

  In order to better understand the relationship of the optic nerve with other brain structures, I decided to partially blind young pike and tench, leaving them afterwards in a vast fishery for many months and up to 1 year or more. The following alterations occurred (which are shown in Figures 15–17; Table VIII): atrophy of the optic nerve of the blind eye, the decrease in volume of the opposite anterior lobe, especially that of the hollow lobe, in which the walls were atrophied; and in the brain of the tench were atrophied any object contained therein. Meanwhile in the other hollow lobe we found above normal swelling of the walls and the eminences within, and in particular the papilla above this, that is, the corpus striatum or optic thalamus (Table VIII, Figure 17b).