Exploring the spatiotopic frame using motion after-effects
26.425, Saturday, May 11, 2:45 - 6:45 pm, Orchid Ballroom
Brice Dassy1, Simon, K, Rushton1, Rob, C, Honey1; 1School of Psychology, Cardiff University
Motion after-effects have been used to probe the existence of spatiotopic map. Turi and Burr (2012) reported spatiotopic adaptation using a single adapting stimulus. If a true spatiotopic map exists then it should be possible to simultaneously adapt two points in separate locations within the putative map. Our preliminary work established that we could obtain adaptation to a single patch and separate patches that could be based on either a retinotopic or in a spatiotopic reference frame. We then tested whether we could obtain adaptation to two adapting patches positioned in different parts of the spatiotopic frame. The build up of motion adaptation was measured with a nulling procedure (staircase run over sessions following Bex et al., 1999) at 5 intervals during the adaptation (total adaptation period of 50s). Participants adapted to a 5deg stimulus composed of 300 dots moving radially inwards or outwards (median 3 deg/sec). In two adapting patches experiments the stimuli were separated by 20deg and had opposite direction radial motion. We obtained adaptation to a single patch positioned in either a retinotopic and spatiotopic frame; and we obtained adaptation to two patches separated in a retinotopic frame. At a group level, there was evidence of adaptation to two separate patches in a spatiotopic frame; but the magnitude of this adaptation was relatively weak and there were notable individual differences.