Visual trajectory perception in humans: is it lateralized? Clues from online rTMS of the middle-temporal complex (MT/V5).

Inconsistent observations have been reported in the literature regarding the asymmetrical contribution of higher visual areas of the left and right hemispheres to visual motion processing. In the present experiment, we tested for hemispheric asymmetry of the middle-temporal complex (V5/MT), which is a key-component of the visual motion network, by using rTMS applied over left or right V5/MT during a visual trajectory perception task. The results showed that the effect of rTMS was to enhance individual hemispheric asymmetries present when the test was performed without rTMS. The more general meaning of these results is that there are robust individual hemispheric asymmetries in motion perception but no general pattern of hemispheric differences.