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August 1944


Author Affiliations


From the Division of Neurological Surgery and the Otho S. A. Sprague Memorial Institute and Division of Psychiatry, University of Chicago.

Arch NeurPsych. 1944;52(2):117-125. doi:10.1001/archneurpsyc.1944.02290320032004

Early in the study of the electrical activity of the cerebral cortex Berger1 noted that a photic stimulus to the retina notably altered the spontaneous alpha rhythm. This observation gave added impetus to the study of the phenomena associated with stimulation of the visual system, which led to the discovery of one of the most interesting methods of modulating the pattern of the occipital electroencephalogram, namely, that of intermittent photic stimulation of the retina, or "photic driving." The modifications of the normal cortical rhythms which may be produced by this method permit certain analyses of normal, and possibly pathologic, visual mechanisms.

HISTORICAL REVIEW  Although Kornmüller2 and Fischer3 demonstrated distinct "on" and "off" action potentials in different parts of the visual system as the result of discrete flashes of light on the retina, and Wang4 showed that repetitive photic stimulation of the retina induced similar action potentials,