Archimedes' spiral


Archimedes' spiral
   Also known as Plateau's spiral. The eponym Archimedes' spiral refers to the Greek mathematician and physicist Archimedes of Syracuse (297-212 BC). The eponym Plateau's spiral refers to the Belgian physicist Joseph Plateau (18011883). Both eponyms are used to denote a device that induces a specific type of "motion aftereffect (MAE), called a "spiral motion aftereffect or spiral MAE for short. Thus the terms Plateau's spiral and Archimedes' spiral refer to a rotating spiral that can be used to induce an illusory sense of expansion or contraction in stationary objects. After viewing the spiral for several minutes and then shifting one's gaze to a stationary object
   Fig. 7 Archimedes' spiral. Source: Plateau, J.A.F. (1878). Bibliographie analytique des principaux phénomènes subjectifs de la vision, depuis le temps anciens jusqu'à la fin du XVIIIe siècle, suivie d'une bibliographie simple pour la partie écoulée du siècle actuel. Mémoires de l'Académie Royale des Sciences, des Lettres et des Beaux-arts de Belgique, Volume 52
(such as a face), the object at hand will appear to expand or contract, depending on the direction of the spiral's rotational movement. The use of Archimedes' spiral played a key role in many of the 19th century studies of MAEs. From the 1960s onwards, it has been used by neurophysi-ologists and neuropsychologists to detect neural processes involved in motion detection. As with other MAEs, the mediation of spiral MAEs has been associated with the process of adaptation, whereby single cells or cell columns within the visual cortex are adapted to the type of movement involved. The spiral MAE has been classified as a special variant of the "waterfall illusion. Spiral MAEs are commonly classified as "physiological illusions. Plateau suffered from blindness due to uveitis and had been blind for 7 years when his paper on the rotating spiral was published.
   References
   Plateau, J. (1850). Vierte Notiz über neue, sonderbare Anwendungen des Verweilens der Eindrücke aufdie Netzhaut. PoggendorffsAnnalen der Physik und Chemie, 80, 287-292.
   Mather, G., Verstraten, F., Anstis, S. (1998). The motion aftereffect: A modern perspective. Cambridge, MA: MIT Press.

Dictionary of Hallucinations. . 2010.