Spatiotopic updating across saccades in the absence of awareness

Abstract

Despite the continuously changing visual inputs caused by eye movements, our perceptual representation of the visual world remains remarkably stable. Visual stability has been a major area of interest within the field of visual neuroscience. The early visual cortical areas are retinotopic-organized, and presumably there is a retinotopic to spatiotopic transformation process that supports the stable representation of the visual world. In this study, we used a cross-saccadic adaptation paradigm to show that both the orientation adaptation and face gender adaptation could still be observed at the same spatiotopic (but different retinotopic) locations even when the adapting stimuli were rendered invisible. These results suggest that awareness of a visual object is not required for its transformation from the retinotopic to the spatiotopic reference frame.

Figure 1.

Experiment paradigms for different conditions. (a) The locations of adaptation and test stimuli before and after the saccade. The cross presents the fixation point. The black arrow represents the saccade direction (from left to right). A, adaptation location (also the full adapt test location); S, spatiotopic location; R, retinotopic location; Cs, control spatiotopic location; Cr, control retinotopic location. (b) Adaptor and test stimuli for tilt aftereffect and face gender aftereffect. (c) Time sequences in the experiment. The adapter was presented for 2 s (top-up adaptation) after 0.8 s fixation in the left cross. After a 0.8 s preview of the right cross, participants need to saccade to the right cross after the extinction of the left cross. Then a test stimulus was present for 0.1s in one of four locations randomly.

Figure 2.

Fitted curves of Tilt Aftereffect results for one participant in four test locations without CFS stimuli: (a) spatiotopic, (b) retinotopic, (c) control-spatiotopic, and (d) control-retinotopic location. Similar results were found for the other 11 participants. Red and blue curves represent clockwise and counterclockwise adaptors, respectively. The vertical bars represent the estimated 50% threshold.

Figure 3.

Adaptation aftereffects (a, TAE; b, FGAE) for the No-CFS and CFS conditions in different locations. Average results from 12 participants show significant TAE and FGAE effects in spatiotopic locations when the adaptors were visible. The effect partially transferred to the two control locations. For invisible adaptor, robust adaptation effects were observed in spatiotopic locations, but not in two control locations. Error bars show ± 1 SE of the mean. Multiple comparisons were Holm corrected. * Adjusted p < 0.05; ** adjusted p < 0.01; *** adjusted p < 0.001.