Ragnar Arthur Granit Swedish neurophysicist, Nobel laureate in Physiology or Medicine, 1967 (shared with Keffer Hartline and George Wald) Date of Birth: 30.10.1900 Country: Sweden

1. Early Life and Education
2. Research in Oxford and Philadelphia
3. Military Service and Nobel Prize
4. Later Research and Honors
5. Publications

Early Life and Education

Ragnar Granit, a Swedish physiologist of Finnish origin, was born into a family of royal foresters. Soon after his birth, the family moved to the outskirts of Helsinki, where his father established a forestry business. Granit received his primary education at the Swedish Lyceum, as his parents were native Swedish speakers from the small island of Korpo in the Baltic Sea. He spent his summers on the island and, as a schoolboy, participated in Finland's struggle for independence from Russia, earning the Cross of Liberty IV Class "with Sword."

In 1919, Granit enrolled at the University of Helsinki. During preparatory summer courses at the Åbo Academy, he initially intended to specialize in experimental physiology, but upon the advice of his uncle, Dr. Lars Ringbom, pursued a full medical degree. His teacher in experimental physiology was Elno Kaila, later a professor of philosophy. He graduated with a Master of Philosophy degree in 1923. In 1926, he accepted Professor Karl Tigerstedt's offer to become an assistant at the Physiological Institute. He received his doctoral degree in 1927 and became a docent in 1929.

Research in Oxford and Philadelphia

In 1928, Granit spent six months in Sir Charles Sherrington's laboratory in Oxford, returning again in 1932-1933 on a Rockefeller Foundation Fellowship. Sherrington's discoveries on stimulation and inhibition inspired Granit's research. From 1929 to 1931, he worked at the Eldridge Reeves Johnson Foundation for Medical Physics at the University of Pennsylvania, invited by Dr. D.W. Bronk. Upon his return to Helsinki, he became a Professor of Physiology (from 1935).

Military Service and Nobel Prize

During the Winter War between Finland and Russia, Granit served as a district physician on three Baltic Sea islands, Korpo, Houtskär, and Iniö, while also performing military medical duties at forts in the region. In 1940, he accepted an offer from the Karolinska Institute in Stockholm. In 1945, his laboratory at the Karolinska Institute was transformed into a department of the Nobel Medical Institute. Construction on new facilities began, which were completed in 1947.

Granit had developed an interest in the physiology of vision as a student. In the mid-1920s, electric impulses in single nerve fibers and later in the optic nerve of the marine eel were recorded for the first time. Working in Oxford, Granit became familiar with Sherrington's research and concluded that inhibitory processes played a significant role in regulating the activity of nerve cells. He began to investigate these processes in vision, particularly in the retina. While at the Johnson Institute, he met H. Keffer Hartline and George Wald, who were working on similar topics.

Initially, Granit used traditional methods to study vision, demonstrating that strong illumination of certain areas of the retina inhibited responses in adjacent areas, which in turn enhanced the eye's perception of contrasts. He also showed (by recording from the entire retina) that the details of the visual image arise from excitation and inhibition within the retina's own nerve network. Upon returning to Helsinki University, Granit became fascinated with color vision.

In the 19th century, German physicist Ferdinand von Helmholtz had proposed that the human eye's ability to distinguish colors was due to the presence of receptors (nerve endings or specialized cells that convert external stimuli into electrical signals) sensitive to different wavelengths of light. Helmholtz (and English scientist Thomas Young independently) believed that the retina contained only three types of receptors, responding to red, green, and violet, with the perception of other colors resulting from combined stimulation of these three primary receptors.

Granit developed a method to record electrical impulses using microelectrodes and demonstrated the existence of three types of receptors, sensitive to red, green, and blue. In the 1950s, Granit's theory was experimentally confirmed by George Wald, who isolated the three corresponding pigments from the receptors.

Later Research and Honors

In 1945, Granit began studying muscle spindles (types of receptors). It was known that these organs controlled static posture and reflex movements. Granit extended this research, attempting to establish connections between muscles, motoneurons (nerve cells controlling muscle contraction and relaxation), and spindle nerves in the spinal cord and brain.

In 1967, Granit (together with Hartline and Wald) received the Nobel Prize in Physiology or Medicine "for their discoveries concerning the primary physiological and chemical visual processes in the eye."

Granit served as a member of the Medical Research Council (1949-1955), President of the Royal Swedish Academy of Sciences (1963-1965), and Vice-President (1965-1969). He received honorary doctorates from the universities of Oslo (1951), Oxford (1956), Hong Kong (1961), Loyola (Chicago) (1969), Pisa (1970), San Marco (Lima), Santiago de Chile, and the National University of Bogotá (all in 1958). He was a foreign member of the Royal Swedish Academy of Sciences (1944), the Paris Academy of Sciences (1947), the Bologna Academy of Sciences (1948), the American Philosophical Society (1954), the Royal Danish Academy of Sciences (1956), the Royal Society of London (1960), the National Academy of Sciences in Washington (1968), an honorary member of the Turin Medical Academy (19612), the Indian Academy of Sciences (1964), and the American Academy of Arts and Sciences (1971). Granit was also an honorary member of several professional societies, including the Swedish Society of Neurology, Ophthalmology, and Clinical Neurophysiology, the International Society for Electroretinography, the biological societies of Montevideo, Santiago de Chile, and Argentina.

Publications

"On the Correlation of some Sensory and Physiological Phenomena of Vision" (London: George Putman, 1938)

"Receptors and Sensory Perception" (Westport, CT: Greenwood Press, 1975)