born Oct. 30, 1900, Helsinki, Fin.
died March 12, 1991, Stockholm, Swed.
Finnish-born Swedish physiologist.
His "dominator-modulator" theory states that in addition to the retina's three kinds of cone cells, which respond to different colours, certain optic-nerve fibres (dominators) respond either to the whole spectrum or to specific colours (modulators). He also proved that light inhibits as well as stimulates optic-nerve impulses; other research helped determine the nerve pathways and processes by which receptors in muscles coordinate muscle action. He shared a 1967 Nobel Prize with George Wald and Haldan Keffer Hartline .