Facilitation and inhibition effects of anodal and cathodal tDCS over areas MT+ on the flash-lag effect

Abstract

The perceived position of a moving object in vision entails an accumulation of neural signals over space and time. Due to neural signal transmission delays, the visual system can not acquire immediate information about the moving object's position. Although physiological and psychophysical studies on the flash-lag effect (FLE), a moving object is perceived ahead of a flash even they are aligned at the same location, have shown that the visual system develops the mechanisms of predicting the object's location to compensate for the neural delays, the neural mechanisms of motion-induced location prediction are not still understood well. Here, we investigated the role of neural activity changes in areas MT+ (specialized for motion processing) and the potential contralateral processing preference of MT+ in modulating the FLE. Using transcranial direct current stimulations (tDCS) over the left and right MT+ between pre-and post-tests of the FLE in different motion directions, we measured the effects of tDCS on the FLE. The results found that anodal and cathodal tDCS enhanced and reduced the FLE with the moving object heading to but not deviating from the side of the brain stimulated, respectively, compared to sham tDCS. These findings suggest a causal role of area MT+ in motion-induced location prediction, which may involve the integration of position information.

Neuroimaging evidence of visual-vestibular interaction accounting for perceptual mislocalization induced by head rotation

“…As to the neural origin for the FLE, Maus et al 8 and Wang et al 9 proved the causal role of human middle temporal complex (hMT+) in FLE with TMS and tDCS, respectively. It is well known that hMT+ plays an essential role in forming the perception of visual motion and object position.…”

“…As to the neural origin for the FLE, Maus et al 8 . and Wang et al 9 . proved the causal role of human middle temporal complex (hMT+) in FLE with TMS and tDCS, respectively.…”