The involvement of early visual areas in the storage of motion aftereffect: A TMS study

After a prolonged exposure to directional motion (adaptation), a subsequently presented stationary test pattern is perceived as moving in the opposite direction to that of the adaptation, leading to an effect known as motion aftereffect (MAE) (cf Mather et al, 2008). In the present study we measured MAE using a stationary test pattern (sMAE) presented 1.5 s after adaptation. To date, the locus of storage of the MAE in humans has been investigated using optic-flow components that selectively tap high-level areas involved in motion processing (ie V5/MT and MST) (Théoret et al, 2002). In order to tap low-levels of motion processing, we investigated the storage of the sMAE using translational moving patterns (ie small Gabor patches) and repetitive transcranial magnetic stimulation (rTMS) delivered during the adaptation-test interval over visual areas V1/V2, V5/MT and a control site (CZ). In contrast with previous studies, results showed a significant decrease in the perceived duration of the sMAE not only when rTMS was delivered over V5/MT, but also when it was delivered over V1/V2, suggesting the involvement of early visual areas in the storage of the sMAE with simple translational motion.