Tilt aftereffect following adaptation to translational Glass patterns

Glass patterns (GPS) consist of randomly distributed dot pairs (dipoles) whose orientations are determined by specific geometric transforms. We assessed whether adaptation to stationary oriented translational GPS suppresses the activity of orientation selective detectors producing a tilt aftereffect (TAE). The results showed that adaptation to GPS produces a TAE similar to that reported in previous studies, though reduced in amplitude. This suggests the involvement of orientation selective mechanisms. We also measured the interocular transfer (IOT) of the GP-induced TAE and found an almost complete IOT, indicating the involvement of orientation selective and binocularly driven units. In additional experiments, we assessed the role of attention in TAE from GPS. The results showed that distraction during adaptation similarly modulates the TAE after adapting to both GPS and gratings. Moreover, in the case of GPS, distraction is likely to interfere with the adaptation process rather than with the spatial summation of local dipoles. We conclude that TAE from GPS possibly relies on visual processing levels in which the global orientation of GPS has been encoded by neurons that are mostly binocularly driven, orientation selective and whose adaptation-related neural activity is strongly modulated by attention.