Abstract
Previous research has extensively explored visual encoding of smoothly curved, closed contours described by sinusoidal variation of pattern radius as a function of polar angle (RF patterns). Although the contours of many biologically significant objects are curved, we also confront shapes with a more jagged and angular appearance. To study these, we introduce here a novel class of visual stimuli that deform smoothly from a circle to an equilateral polygon with N sides (AF patterns). Threshold measurements reveal that both AF and RF patterns can be discriminated from circles at the same deformation amplitude, approximately 18.0arcsec, which is in the hyperacuity range. Thresholds were slightly higher for patterns with 3.0 cycles than for those with 5.0 cycles. Discrimination between AF and RF patterns was 75% correct at an amplitude that was approximately 3.0 times the threshold amplitude, which implies that AF and RF patterns activate different neural populations. Experiments with jittered patterns in which the contour was broken into several pieces and shifted inward or outward had much less effect on AF patterns than on RF patterns. Similarly, thresholds for single angles of AF patterns showed no significant difference from t...Continue Reading
References
Jan 1, 1974·Kybernetik·R F Quick
Jan 1, 1993·Science·J L GallantD C Van Essen
Jan 20, 1999·Vision Research·F WilkinsonC Habak
Sep 14, 2000·Neuron·J L GallantJ A Mazer
Dec 5, 2000·Current Biology : CB·F WilkinsonM A Goodale
Nov 12, 2002·Nature Neuroscience·Anitha Pasupathy, Charles E Connor
Nov 27, 2002·Vision Research·Hugh R WilsonFrances Wilkinson
Feb 22, 2003·Vision Research·Gunter LofflerFrances Wilkinson
Oct 23, 2003·Visual Neuroscience·Jay Hegdé, David C Van Essen
Apr 15, 2005·Journal of Cognitive Neuroscience·Alice J O'TooleJames V Haxby
Sep 18, 2007·Nature Neuroscience·Akiyuki AnzaiDavid C Van Essen
Aug 16, 2008·Vision Research·Jason Bell, David R Badcock
Oct 5, 2010·Journal of Vision·Jason BellJonathan W Peirce
Dec 15, 2010·Journal of Vision·J Edwin DickinsonDavid R Badcock
Feb 15, 2011·Current Biology : CB·Eric T CarlsonCharles E Connor
Mar 21, 2012·Vision Research·Gunnar SchmidtmannGunter Loffler
Dec 1, 2012·Journal of Vision·J Edwin DickinsonDavid R Badcock
Jun 26, 2013·Neuron·Anirvan S NandyJude F Mitchell
May 16, 2014·The Journal of Neuroscience : the Official Journal of the Society for Neuroscience·Shahin NasrRoger B H Tootell