Motion after-effect due to binocular sum of adaptation to linear motion

Abstract

The motion after-effect (MAE) can be elicited by adapting observers to global motion of randomly distributed dots before they view a display containing dots moving in random directions, but no global motion. Experiments by others have shown that if the adaptation stimulus contains two directions of motion, the MAE points opposite to the vector sum of the adapting directions. The present study investigated whether such vector addition in the MAE could also occur if the two directions of motion were presented to separate eyes. Observers were adapted to different, but not opposite, directions of motion in the two eyes. Either the left eye, the right eye, or both eyes were tested. Observers reported the direction of perceived motion during the test. When they saw the test stimulus with both eyes, observers reported seeing motion in the direction opposite that of the vector sum of the adaptation directions. In the monocular test conditions observers reported MAE directions opposite to the corresponding monocular adaptation directions. In a second experiment we verified that subjects had interocular transfer of the MAE. Together these results are consistent with a model in which (1) addition of adaptation directions occurs at a binocular site; (2) directional adaptation occurs at a monocular site; and (3) monocular adaptation is able to change the threshold for obtaining an MAE at the binocular site, thus acting like binocular adaptation in interocular transfer of the MAE.

Velocity Dependence of the Interocular Transfer of Dynamic Motion Aftereffects

“…A study on binocular MAEs for adaptation to random-dot kinematograms and testing with dynamic noise was reported by Grunewald and Mingolla (1998). It is important in the present context, as our study was partly motivated by the same theoretical model (Grunewald and Lankheet 1996;van de Grind et al 2003).…”

“…Thus, there is a binocular integration stage combining adaptation directions in the dMAE, but this shows up only if the test is binocular, not if it is monocular. In their second experiment Grunewald and Mingolla (1998) specifically studied IOT for the same adaptation conditions. The transferred dMAEs tended to have the same direction as the ipsilateral dMAE, so IOT was direction specific.…”

“…One difference with other studies of the dMAE, as reviewed above, was the speed. Grunewald and Mingolla (1998) used a relatively high adaptation speed (20 deg s À1 ), whereas the other studies were done with low speeds (1.5^2 deg s À1 ).…”

Three-dimensional motion aftereffects reveal distinct direction-selective mechanisms for binocular processing of motion through depth

“…However, motion processing channels exhibit significant binocular crosstalk, evidenced in varying degrees of reported inter-ocular transfer of monocular MAE (Anstis & Duncan, 1983; Grunewald & Mingolla, 1998; Lehmkuhle & Fox, 1976). Monocular MAEs assessed after dichoptic 3D adaptation were weaker than either 2D or 3D MAEs, equivalent to approximately 9% motion coherence (Figure 8A, 3 β = 0.093, CI 95 = [0.082, 0.104]).…”

The temporal sequence of evoked and induced cortical responses to implied‐motion processing in human motion area V5/MT+

“…, 1986; Liu et al. , 2004) and the motion after‐effect (Anstis & Duncan, 1983; Grunewald & Mingolla, 1998), which are unrelated to knowledge and beliefs, representational momentum is evidence for the cognitive representation of motion.…”