Fig. 1

Diagrams showing the physical (Panel a) and perceived (Panels b and c) spatial relationship between the prepulse (the music note) and the noise masker (noise waveform). (Panel a) Both the prepulse and the noise masker were delivered by each of the two horizontally separated headphones. (Panel b) The onset of the prepulse delivered by the left headphone led that from the right headphone by 3 ms, and the image of the prepulse (music note in the circle) was perceived as coming from the left headphone; the onset of the masker from the right headphone led that from the left headphone by 3 ms, and the image of the masker (noise waveform in circle) was perceived as coming from the right headphone. Thus, the prepulse and the noise masker were perceived spatially separated. (Panel c) Both the onset of the prepulse and the onset of the masker presented from the left headphone led those from the right headphone, and the image of the prepulse (music note in circle) and that of the masker (noise waveform in circle) were perceived spatially co-located