Foveal versus parafoveal scanpaths of visual imagery in virtual hemianopic subjects

Sophisticated string analysis [compressed regional string analysis, cRSE] shows significant differences following therapeutical masking of the foveal region during a virtual hemianopia. The visual imagery scanpath is done over a compressed mental image that needs longer fixation duration but fewer saccades than the real image. Combination of different viewing tasks with types of pictures permits to show how scanpath top-down strategies can be enforced or decreased by proper combination of task and picture; this is influenced by the mask of fovea versus no-mask of fovea difference, with bottom up mechanisms becoming more important with loss of foveal viewing strategies in the mask condition.