Pulfrich's Phenomenum Re-examined In Light Of Visual Cortex Histoarchitecture

Pulfrich's phenomenon, first described In 1922, is the illuslon whereby a pendulum swinging In a frontal plane appears to move In an elliptical path when viewed with one eye covered with a liter. The object is perceived as travelling In an orblt away from the filter-covered eye. This phenomenon has been explored as a clinical test: the effect Is a sensitive indicator of optic nerve dysfunction. Pulfrich thought the filter directly slowed retinal function. More recent explanations evoke delays of optic nerve conduction that If unilateral can produce a time lag between the visual Input from each eye leading to the stereo-illusion. It is interesting to consider Pulfrich's phenomenon In the light of recent advances In the understanding of visual cortex organization.