Justo Gonzalo y Rodríguez-Leal (March 2, 1910 – September 28, 1986), was a Spanish neuroscientist who was born in Barcelona and died in Madrid. After obtaining his bachelor's degree in medicine he specialized in Austria and Germany (1933–1935) with a grant from the Junta para Ampliación de Estudios e Investigaciones Científicas [Committee for the Extension of Studies and Scientific Research], and subsequently carried out extensive research on human brain functions based largely on brain injuries from the Spanish Civil War (1936–1939). He characterized what he called the central syndrome of the cortex (multisensory and bilateral disorder caused by a unilateral lesion in a parieto-occipital association area), which he interpreted based on physiological laws of nervous excitability and a model of brain dynamics where the cortex is conceived as a dynamic functional unit with specificity in gradation, providing a solution to the question of brain localization. He described and interpreted phenomena such as inverted perception and multisensory and motor facilitation, among others. By applying concepts of dynamic similarity, he formulated and proved allometric power laws in the loss of functions and in the sensory organization. He belonged to the Spanish National Research Council (CSIC) from 1942 until his retirement, and he was lecturer of 21 PhD courses (1945–1966) on brain physiopathology at the Faculty of Medicine in the University of Madrid. He received awards from the CSIC (1941), the Royal Academy of Medicine (1950) and the Spanish Society of Psychology (1958).
His scientific contribution
His book Investigaciones sobre la nueva Dinámica Cerebral. La actividad cerebral en función de las condiciones dinámicas de la excitabilidad nerviosa Gonzalo, J. (1945, 1950, 1952, 2010, 2023). Dinámica Cerebral, Open Access. Edición facsímil 2010 del Vol. 1 1945, Vol. 2 1950 (Madrid: Inst. S. Ramón y Cajal, CSIC), Suplemento I 1952 (Trab. Inst. Cajal Invest. Biol.) y 1ª ed. Suplemento II. Red Temática en Tecnologías de Computación Artificial/Natural (RTNAC) y Universidad de Santiago de Compostela (USC). . English edition 2023 Brain Dynamics (Vols.1 and 2, Supplements I and II), Ediciones CSIC, Open Access. contains part of his fundamental contributions and is the first time that the term Brain Dynamics is used in the scientific literature to describe the organization of sensory functions. It consists of two volumes, the first one published in 1945 focused on visual functions and the second one published in 1950 dedicated to tactile functions and where concepts exposed in the first one are expanded. In this book the author exposes what he called central syndrome of the cortex, as a multisensory affection with bilateral symmetry, originated by a unilateral parieto-occipital cortical lesion in an associative area equidistant from the visual, tactile, and auditory projection areas.
The syndrome presents dynamic effects such as the multisensoriality and symmetrical bilaterality of the disorder, which also involves all functions from simple excitability to more complex functions. Another dynamic effect is the progressive loss of functions and a decomposition of some of them into partial reactions as the intensity of the stimulus decreases. This gives rise, for example, to tilted or even inverted vision, in which the image is perceived as increasingly tilted at the same time as it loses shape, color and size until it is almost inverted in the most acute case. This was the first exhaustive study of inverted or tilted vision (Gonzalo, 1945). The author also observed inverted perception in touch (1950) and hearing (1952), for none of which there were precedents, and generalized the inversion process in the central syndrome to sensory systems of a spatial nature. Gonzalo-Fonrodona, I. (2007) «Inverted or tilted perception disorder». Revista de Neurología 44, 3, 157-165. Gnosic or cognitive and complex functions are the first to be lost since they require greater brain excitation and, thus, greater brain integration. Thus, a continuity was established between elementary and higher sensory functions, based on the same physiological laws.
A dynamic phenomenon related to the previous one is the disappearance in part of some disorders by intensification of the stimulus or by temporal summation (iteration of the stimulus), or by the emerging capacity for facilitation, according to which the functions are recovered by the presence of another type of stimulus of the same or different modality (multisensory facilitation), or by motor activity such as muscular effort, of all of which there was no precedent of detailed studies. For example, tactile and auditory stimuli, and in particular muscular effort, improve perception, partly compensating for the deficit of nervous excitation due to the loss of nonspecific (or multispecific) neuronal mass caused by the lesion. For example, the visual field, which shows concentric reduction, increased up to 5 times in the most acute case, and the image recovered the correct orientation by means of a strong muscular contraction. This capacity is greater the larger the brain lesion and the lower the intensity of the original stimulus.
The author observed and studied other remarkable phenomena such as color delocalization, reversal in motion perception, the disorder by which the patient was able to read a text equally well upright or rotated 180 degrees without noticing any difference, and the disorder of allocentric orientation, among others.
His research filled the gap then existing between brain pathology and the physiology of the nervous system, since the phenomena observed were governed by the laws of nervous excitability, which was a radical change with respect to the concepts in use at that time.
Gonzalo found not only the cases described in his book but about 35 cases of central syndrome of varying intensity (Gonzalo, 1952). The author also analyzes in depth the famous Schneider case of Goldstein and Gelb (1918), Goldstein K., Gelb A. (1918) «Psychologische Analysen hirnpathologischer Fälle auf Grund von Untersuchungen Hirnverletzer. I. Abhandlung: Zur Psychologie des optischen Wahrnehmungs und Erkennungsvorganges». Zeitschrift fur die gesamte Neurologie und Psychiatrie, 41: 1-142. which he interprets according to the aforementioned syndrome.
He proposed a spiral development of the sensory field in the integrative brain process (Gonzalo, 1951, 1952) and introduced the idea of functional brain gradients across the cortex (Gonzalo, 1952). These gradients are functions in gradation that represent the density of specific sensory function at each point in the cortex, related to the density of specific neurons and their connections, taking a maximum value in the corresponding projection area and gradually decreasing throughout the cortex, with the end of the decline reaching other projection areas. The multiple types of cortical syndromes from first hand and other authors was interpreted according to the model of gradients, depending on the position and magnitude of the lesion, finding a continuous transition between the syndromes of the projection area and the central one.
Gonzalo later developed the concepts of dynamic similarity and allometry applied to the central syndrome, this being understood as the result of a change of scale in the nervous excitability of the cerebral system with respect to the normal case. According to the principle of dynamic similarity, the change of scale in a system results in its different parts changing differently (allometrically). He then found allometric relationships, scaling power laws, between the different sensory functions. The gradual loss of these functions in the central syndrome was thus interpreted and formalized. These concepts, including that of gradients, were also applied to the language system. All this last research remained unpublished and is partially collected in Supplement II in the reprint of Gonzalo's work (Gonzalo, 2010) and in later works, Gonzalo-Fonrodona, I.; Porras, M.A. (2014). «Nervous excitability dynamics in a multisensory syndrome and its similarity with normals. Scaling Laws» Open Access. In: Costa, A.; Villalba, E. (Eds.) Horizons in Neuroscience Vol. 13: Chap.10, pp. 161-189. (see below the works of Gonzalo-Fonrodona and Porras in the section 'Works on Justo Gonzalo's research work').
Early years
Justo Gonzalo was born and lived in Barcelona, Spain; then spent several years in Valencia, Spain; returned to Barcelona, and finally moved to Madrid, Spain, to study medicine, obtaining his bachelor's degree there in 1933. During 1933–34, he carried out studies at the Nervenklinik (mental hospital) of the University of Vienna, on clinical neurology and animal testing with Hans Hoff, and also on brain cytoarchitecture with Otto Pötzl, at Constantin von Economo's laboratory. During 1934–35 he carried out research on brain pathology with Karl Kleist at the mental hospital of the Goethe University Frankfurt, granted a scholarship by the Junta para Ampliación de Estudios e Investigaciones Científicas [Committee for the Extension of Studies and Scientific Research]. After returning to Madrid, he combined clinical neurology at the then called Hospital General de Madrid with brain anatomoclinical research at the Cajal Institute.
It was during this time that he wrote his first works (see section: Justo Gonzalo's published works).
Spanish Civil War and post-war period
After the outbreak of the Spanish Civil War (1936–1939), he resumed the neurological activities at the Hospital General de Madrid and the brain anatomoclinical studies at the Cajal Institute until he practiced war medicine in the Republican front (1937). He was called in 1938 by Gonzalo Rodríguez Lafora, head of the Center for Brain Injuries at Neurological Military Hospital of Godella (Hospital Militar Neurológico de Godella) in Valencia, to work there as a neurologist, Monteagudo-Soto. M. J., Chisvert-Perales, M (2018) Revista de Historia de la Psicología, 39(3), p. 28–37. https://doi.org/10.5093/rhp2018a14 Picardo Castellón, M. «Experiencia personal en un hospital quirúrgico de primera línea durante nuestra guerra civil» where he stayed until the end of the war. During this period, he conducted detailed observations on numerous brain-injured subjects and performed, despite the extreme conditions, a fundamental part of his research. Some selected cases were carefully study in the course of several years.
In the summer of 1938, he discovered, among other singular disorders, near-inverted vision in the war wounded man he termed case M, and in 1939 characterized what he called central syndrome of the cortex, which exhibited peculiar dynamic phenomena. The observations could not be understood until he uncovered the permeability developed by this type of patient to temporal summation and multisensory and motor facilitation.
The first results were presented in 1941 to the Spanish National Research Council in a 94-page report in Spanish entitled Investigaciones sobre Dinámica Cerebral. La dinámica en el sistema nervioso. Estructuras sensoriales por sincronización cerebral (Research on Brain Dynamics. Dynamics in the nervous system. Sensory structures by brain synchronization), which was awarded by this organism that same year. During the years 1942–1944, established in Madrid and sponsored by the Cajal Institute, he obtained a more precise quantitative evaluation of the phenomena, in spite of the difficulties in obtaining the most indispensable experimental instruments.
In 1945, the Cajal Institute, now part of the Spanish National Research Council, published the first volume of his book on Brain Dynamics, mainly devoted to visual functions. Apart from local references to the aforementioned volume at the time of its publication,
d'Ors, E. (1945)"Estilo y Cifra". Diario La Vanguardia Barcelona 27 junio 1945: p. 3