Abstract
While scanning our environment, we move our eyes around three times per second. Each of these saccades is preceded by an attention shift, increasing visual sensitivity at the saccade target. Previous studies suggest that pre-saccadic enhancement is more pronounced for high than for low spatial frequency (SF) content (Li, Pan, & Carrasco, 2018). This conclusion, however, relies on experimental designs that probed sensitivity to a small range of SFs. Relative enhancement benefits for high over low SFs may therefore reflect local changes in the sensitivity profile which do not transfer to a wider range of SFs. To assess the impact of saccade preparation on the overall shape of the peripheral sensitivity profile, we asked observers to make a saccade towards one of two dynamic noise streams presented at 10 dva eccentricity. Before the eye movement, an oriented grating (the probe) appeared at the saccade target and observers reported its orientation. Crucially, the probe’s SF varied across trials, ranging from 1–5.5 cyc/deg. In order to describe the shape of the sensitivity profile, we fitted log-parabolic functions to measured accuracies. During saccade preparation, the profile shifted upwards, resulting in an increase in peak sensitivity (i.e. the maximum accuracy obtained). As the probe appeared closer to saccade onset, the SF at which participants reached peak sensitivity increased gradually. We furthermore observed a decrease in the bandwidth of the profile. In accordance with previous findings, the combination of these modulations entailed that pre-saccadic enhancement increased with SF up to 2.5 cyc/deg. Sensitivities to even higher SFs, however, profited less from saccade preparation. We conclude that pre-saccadic sensitivity changes at the saccade target are best described as a global reshaping of the peripheral sensitivity profile. As a consequence, peripheral sensitivities may gradually emulate the characteristics of foveal vision.