Figure 4

Schematic illustration of each spatial orientation task and visual stimuli. (A) Participants were asked to align the visual line (denoted as red lines) along the perceived direction of the body longitudinal axis (SVBA task) or gravitational vertical (SVV task). Adjustment errors in each task (denoted as arrows) were calculated as the angular bias of the subjective directions of body longitudinal axis or vertical (solid lines) from the objective directions (dotted lines). (B) Illustration of the visual stimuli on the display as seen by the participants in the optokinetic stimulation (OKS) conditions. Many dots were randomly positioned around the visual line, and they rotated uniformly clockwise (CW) or counterclockwise (CCW) around the center of the display during the SVBA or SVV tasks.