[Thanks to Adrian-in-Berkeley. This may add a bit of flesh to the Petitot-Connes-Sha;) thesis that objects are invariants of Lie groups for a suitably defined group of actions in the experienced world. See also, Madeline Gins and Arakawa's Organism-That-Persons.]
How the unstable eye sees a stable and moving world
School of Optometry, UC Berkeley
Wednesday, December 14 at 12:00
How is it that the eye can have an exquisite sense of motion even while the
retinal image of the stable world during fixation is in constant motion?
Several hypotheses have arisen: The "efference-copy" hypothesis holds that
efferent signals derived from the opto-motor control circuitry are used to
exactly offset the image instability induced by eye-motion. The
"data-driven" hypothesis holds that image stabilization is computed from the
content of the images, deriving compensatory information from the
displacement of image features over time. Or, we might just suppress the
lowest common motion of any visual scene. In any case, the physiology
underlying this phenomenon remains largely unknown. Recent experiments from
our lab using an adaptive-optics-based eye tracker have revealed that the
percept of motion bears a different relationship to actual eye-motion than
any extant hypothesis predicts. We found that stimulus motions that have
directions which are consistent with eye-motion, but largely independent of
magnitude of that motion, produce the most stable percepts. These new
observations not only challenge all existing theories but, more importantly,
define a simpler path toward a physiological solution.
1. Helmholtz,H. Helmholtz's Treatise on Physiological Optics. Optical
Society of America, Rochester (1924).
2. Poletti,M., Listorti,C. & Rucci,M. Stability of the visual world during
eye drift. J. Neurosci. 30, 11143-11150 (2010).
3. Murakami,I. & Cavanagh,P. A jitter after-effect reveals motion-based
stabilization of vision. Nature 395, 798-801 (1998).
Bruno A. Olshausen
Helen Wills Neuroscience Institute & School of Optometry Director, Redwood
Center for Theoretical Neuroscience UC Berkeley 575A Evans hall, MC 3198
Berkeley, CA 94720-3198
(510) 642-7250 / 2-7206 (fax)