Gunnar Svaetichin

Gunnar Svaetichin (1915-1981) mastered high impedance microelectrode techniques while studying neurophysiology in the Karolinska Institute with Ragnar Granit (nobel prize, 1967). These enabled intracellular recording of light responses from retinal interneurons, a field that he founded. It was an imaginative area to pursue in the 1940s. He is the discoverer of S-potentials, now known to be retinal horizontal cell responses, and discovered both color opponent and non opponent types. The discovery of neural color opponency ranks with the most significant findings in color vision in the 20th century. The later decades of his career were spent at the Venezuelan Institute for Scientific Research.^[1]

Early life and family

He was born in 1915 in Karis, Finland, the son of the engineering surveyor Volmar Svaetichin and his wife Ellen (born Nordstrom).

Education

Gunnar Svaetichin in his student cap

After attending schools in Karis and Helsinki, he went on to graduate from medical school at the University of Helsinki, where he also worked as a researcher. During his medical studies in Helsinki, Svaetichin got to know the young Ragnar Granit, who had returned after some years in the US and Oxford and become a professor of physiology.^[2] His first work as a doctor was when the Finnish winter war broke out and Svaetichin was drafted and sent to a first aid station located just behind the front lines.

Research Work

In cooperation with Ragnar Granit, Svaetichin developed a new methodology for electrophysiological study of vision. They made fine needle electrodes that could register signals from the major nerve cells in the retina, which sends its threads in the optic nerve to the brain. It was with this technique Ragnar Granit could perform his famous studies of color vision.

In 1956,^[3] showed by examining the external layers of fish retinas that electroretinograms display particular sensitivity to three different groups of wavelengths in the areas of blue, green and red. This provided the first biological demonstration in support of the Young-Helmholtz trichromatic theory. He also gave name to the S-potential,^[4] which was the first experimental evidence that opponency existed in the visual system.

References

1. http://webvision.med.utah.edu/book/part-v-phototransduction-in-rods-and-cones/horizontal-cells/
2. Yngve Zotterman (Dagens Nyheter, 1981)
3. Svaetichin,G. (1956). Spectral response curves from single cones, Actaphysiol. scand. 39, Suppl. 134, 17-46.
4. Drujan BD, Svaetichin G., Laufer G. (1982). The S-Potential. AR Liss.

Additional reading

Jameson D., Hurvich L.M. (1982). Gunnar Svaetichin: man of vision. Prog Clin Biol Res., 13, 307-10.

http://www.hubel.med.harvard.edu/book/ch8.pdf

http://www.adsabs.harvard.edu/abs/1984Natur.308..360H

http://www.nature.com/nature/journal/v308/n5957/abs/308360a0.html

http://www.americanscientist.org/issues/id.841,y.2003,no.1,content.true,page.1,css.print/issue.aspx

Book prepared posthumously in Gunnar Svaetichin's honor.