Abstract
Visual sensitivity is strongly impaired around saccades, a phenomenon known as saccadic suppression. This robust phenomenon does not constitute a mere global suppression, but instead shows selectivity for low spatial frequencies, which has been used to suggest selective motor-driven suppression of magnocellular visual pathways (e.g. Burr et al., 1994). However, neural studies failed to reveal selective magnocellular pathway suppression. Moreover, Idrees et al. (VSS, 2018) recently described a surprisingly far-reaching contribution of visual image processing mechanisms to saccadic suppression, without the need to invoke explicit motor-based suppression commands. Here we show that this is also true for selective suppression of low spatial frequencies. Six participants localized a brief (~12 ms) vertical Gabor grating flashed at one of four locations (4-AFC paradigm). The gratings had one of 6 spatial frequencies (0.41–6.83 cycles/deg), and they were presented over a uniform gray background in a dark room. At a radius >10 deg from display center, the gray background was replaced by either a coarse or fine band-passed random texture (as in Idrees et al., VSS, 2018), in order to simulate a “virtual monitor” edge. In one condition, gratings were presented peri-saccadically with saccades directed towards display center; in another, gratings appeared during fixation after the “virtual monitor” and surrounding texture were translated in a saccade-like manner, again towards display center. With a coarse peripheral context, selective suppression of low spatial frequencies occurred with or without saccades, therefore due to saccade-like image translations. Even more surprisingly, when the surround was fine, both real and “simulated” saccades exhibited suppression that was not selective for spatial frequency, violating (Burr et al., 1994). Thus, selective or unselective suppression happens with or without saccades, as a function of saccade-induced image translations and peripheral visual contexts. Our results support the view that saccadic suppression is a primarily visual phenomenon.