title: Principal component analysis of Motokawa's data on wavelength dependence of retinal processes.
abstract: Electric excitability of the human eye as determined by measuring the threshold for a sensation of phosphene in response to electric stimulation of the eye was found by Koiti Motokawa to increase temporarily after a brief illumination (J. Neurophysiol., 1949, 112, 475-488). While changing the wavelength of illuminating light widely, he found that the time course of the variation in the eye's electric excitability after illumination differed characteristically according to the wavelength. His data on this point (Tohoku J. exp. Med., 1949, 51, 197-205) were subjected to the principal component analysis. Three components were found necessary and sufficient for their linear combinations to reproduce time courses of the excitability enhancement after illumination with lights of varying wavelengths; one of the three components makes a great contribution to the excitability enhancement by green lights, the other to the one by red lights and the remainder to the one by blue lights. This is in support of Motokawa's view that his data are interpretable as summation effects of the three retinal processes which are excited preferentially by red, green and blue lights, respectively.
mesh_terms: D004558:Electric Stimulation; D004594:Electrophysiology; D006801:Humans; D008027:Light; D010775:Photic Stimulation; D012160:Retina / Q000502:physiology*