Annu. Rev. Neurosci. 1995. 18:359-83 LOCALIZATION OF BRAIN FUNCTION: The Legacy of Franz 1 Joseph Gall (1758-1828) S. Zola-Morgan Veterans Affairs Medical Center, San Diego, and University of California, San Diego, La Jolla, California 92093-0603 KEY WORDS: craniology, cognition, organology, phrenology, soul A BRIEF HISTORY OF IDEAS ABOUT LOCALIZATION OF BRAIN FUNCTION The First Era: Antiquity to the Second Century AD The history of ideas about localization of brain function can be divided roughly into three eras. During the first era, which spans from antiquity to about the second century AD, debate focused on the location of the soul, i.e. what part of the body housed the essence of being and the source of all mental life (for reviews, see Finger 1994, Gross 1987b, Star 1989). In an early and particularly prophetic Greek version of localization of function, the soul was thought to Access provided by CASA Institution Identity on 08/05/20. For personal use only. Annu. Rev. Neurosci. 1995.18:359-383. Downloaded from www.annualreviews.org be housed in several body parts, including the head, heart, and liver, but the portion of the soul associated with intellect was located in the head (McHenry 1969). The individual who has been viewed by many historians as having the greatest influence during this era was Galen (130-200 AD), an anatomist of Greek origin. Using animals, he performed experiments that provided evidence that the brain was the center of the nervous system and respon­ sible for sensation, motion, and thinking (Finger 1994, Gross 1987b, Hall 1968). IThe US government has the right to retain a nonexclusive, royalty-free license in and to any copyright covering this paper. 359 360 ZOLA-MORGAN The Second Era: The Second Century to the Eighteenth Century In this era the debate focused on whether cognitive functions were localized in the ventricular system of the brain or in the brain matter itself. It appears that Galen associated higher cognitive functions with the brain matter (Mc­ Henry 1969, Gross 1993, Finger 1994), although some of his later writings continued to emphasize the importance of the ventricles (Duckworth 1962). The influenceof the Church during this era cannot be overstated; for example, ethereal spirits and ideas were believed to flow through the empty spaces of the brain's ventricles. Nevertheless, by the fifteenth and sixteenth centuries individuals such as da Vinci (1452-1519) and Vesalius (15 14-1564) were questioning the validity of ventricular localization (McHenry 1969). Finally, during the seventeenth century, partly as a result of the strongly held views and prolificwritings of Thomas Willis (1621-1675), and during the eighteenth century, with the publication of clinical descriptions of cognitively impaired patients accompanied by crude descriptions of brain damage (Baader 1762, Clendening 1942), the view that intellectual function was localized in brain matter and not in the ventricles became solidified. The Third Era: The Nineteenth Century to the Present During this era, the debate has focused on how mental activities (or cognitive processes) are organized in the brain. An early idea, which became known as the localizationist view, proposed that specific mental functions were carried out by specific parts of the brain. An alternative idea, which became known as the equipotential view, held that large parts of the brain were equally involved in all mental activity and that there was no specificity of function within a particular brain area (Squire 1987, Clark & Jacyna 1987). The present review focuses on a portion of the current era, i.e. the period from the 1790s to the 1 860s. Specifically, it considers the impact on ideas Access provided by CASA Institution Identity on 08/05/20. For personal use only. Annu. Rev. Neurosci. 1995.18:359-383. Downloaded from www.annualreviews.org about localization of brain function made by the early nineteenth century localizationist Franz Joseph Gall. The movement associated with Gall came historically and generically to be known as phrenology (although as I describe below, Gall did not favor this term). This review first describes the European zeitgeist within which Gall's localizationist views emerged. It then considers the points of view held by the two major protagonists of the localizationist movement during the first half of the nineteenth century, Franz Joseph Gall and Johann Spurzheim. I suggest that Gall has not been given appropriate credit and recognition for his views, which were more fundamental to the development of contemporary ideas about localization of function than is usually recognized. Although Gall was a good scientist and a superb neuro­ anatomist, his reputation became mixed with and was transcended by that of LOCALIZATION OF FUNCTION 361 Spurzheim. A new hypothesis is presented to explain the major schism that occurred between them. Next, I discuss the reaction against the localization movement during the nineteenth century. Finally, I identify several specific contributions to the brain sciences made by Gall and the legacy of his doctrine to contemporary neuroscience. FRANZ JOSEPH GALL AND EIGHTEENTH CENTURY LOCALIZATIONIST VIEWS Gall's Early Years It is somewhat ironic that Gall became one of the most influential scientists of the nineteenth century based not on his reputation as an outstanding scholar, physician, and anatomist, but instead on his identity by the scientific commu­ nity and the general population as the founder of "phrenology." As I describe below, Gall neither invented nor approved of the term phrenology, nor was he pleased to be associated with the phrenological movement. This section briefly describes Gall's early life and then his activities as a young physician and scientist in Vienna. Franz Joseph Gall (Figure 1) was born in 1758 in Tiefenbronn, Badenia (Germany), and died in 1828 in Paris. By the early part of his life, there had Access provided by CASA Institution Identity on 08/05/20. For personal use only. Annu. Rev. Neurosci. 1995.18:359-383. Downloaded from www.annualreviews.org Figure 1 Franz Joseph Gall (1758-1828). (From Haymaker & Schiller 1953.) 362 ZOLA-MORGAN already developed a popular view in Europe that temperament and psycholog­ ical characteristics could be explained by certain physical characteristics of the body and face (Finger 1994). By the age of nine, Gall had already formu­ lated a hypothesis, based upon anecdotal evidence from the performance of his schoolmates, that good verbal memory was associated with bulging eyes. (The explanation for this relationship that Gall later developed was that the specialized faculty of verbal memory was located in the front part of the brain, and when verbal memory was especially developed, the orbits were pushed forward.) Gall moved to Vienna and graduated from medical school in 1785. During the 20 years he spent in Vienna, Gall developed the ideas that led to his doctrine of localization. Though he labeled his contributions "physiology," they were not physiology in the sense that we now use the term; by current terminology, it would be more appropriate to describe his doctrine of localization as a combination of psychology and functional anatomy (Acker­ knecht 1973). Gall apparently did not publish any formal versions of his doctrine while in Vienna, although he did give public lectures in which he elaborated its principal ideas. After moving to Paris at the tum of the century, Gall became well known as a descriptive anatomist. A distinction must be made, however, between two kinds of anatomy associated with Gall. On the one hand, as a result of his anatomical dissections, Gall made several important anatomical discoveries that stand today. On the other hand, Gall also attempted to develop a functional anatomy that served the purpose of his doctrine of localization. Gall's func­ tional anatomy was not grounded in empirical analyses and bore no relationship to his very careful and thorough descriptive anatomy. For Gall, descriptive anatomy and functional anatomy were entirely separate from each other. He argued that it was rare for (descriptive) anatomy to lead to the elucidation of function: " .. .it is thus without the help of any anatomical dissection that we have ourselves made most of our physiological discoveries" (Gall & Spurzheim Access provided by CASA Institution Identity on 08/05/20. For personal use only. Annu. Rev. Neurosci. 1995.18:359-383. Downloaded from www.annualreviews.org 1809, Clarke & Jacyna 1987; the term physiological in this context refers to relationships between structure and function in the brain). Gall's ill-fated association with the doctrine of phrenology unfortunately overshadowed his important and lasting contributions to anatomy. Even Flour­ ens, who severely criticized Gall and his doctrine, wrote, "I shall never forget the feeling I experienced the first time I saw Gall dissect a brain. It seemed to me that I had never seen this organ before" (Flourens 1845). Period of Transition: The Late Eighteenth Century Gall's ideas about the localization of cognitive functions began to tear at the religious and social fabric of the late eighteenth century. In particular, his LOCALIZATION OF FUNCTION 363 Fi�. I.-Tile Illm.'noiu)(i('·ill system IIC Cull Sl't'li Crnlll I'"i;!. 2.-'I'lIt, Ilhrcnnlogical system nf Cnll, prnrilt·. Fllr IlIImhers St'(' hod. frontill viow. Figure 2 Gall's system of organology seenfrom right profile and frontal views. The organs were, for the most part, bilateral. Gall's 27 organs representing specificfunctions of the mind were divided into two groups. A There were 19 organs common to humans and animals: 1. instinct of reproduction; 2. love of offspring; 3. affection, friendship; 4. instinct of self-defense, courage; 5. carnivorous instinct, tendency to murder; 6. guile, acuteness, cleverness; 7. the feeling of property, the instinct of stocking up on food (in animals), covetousness, the tendency to steal; 8.