Visual field differences in temporal synchrony processing for audio-visual stimuli.

Deborah Apthorp,Yasuhiro Takeshima

doi:10.1371/journal.pone.0261129

Abstract

Audio-visual integration relies on temporal synchrony between visual and auditory inputs. However, differences in traveling and transmitting speeds between visual and auditory stimuli exist; therefore, audio-visual synchrony perception exhibits flexible functions. The processing speed of visual stimuli affects the perception of audio-visual synchrony. The present study examined the effects of visual fields, in which visual stimuli are presented, for the processing of audio-visual temporal synchrony. The point of subjective simultaneity, the temporal binding window, and the rapid recalibration effect were measured using temporal order judgment, simultaneity judgment, and stream/bounce perception, because different mechanisms of temporal processing have been suggested among these three paradigms. The results indicate that auditory stimuli should be presented earlier for visual stimuli in the central visual field than in the peripheral visual field condition in order to perceive subjective simultaneity in the temporal order judgment task conducted in this study. Meanwhile, the subjective simultaneity bandwidth was broader in the central visual field than in the peripheral visual field during the simultaneity judgment task. In the stream/bounce perception task, neither the point of subjective simultaneity nor the temporal binding window differed between the two types of visual fields. Moreover, rapid recalibration occurred in both visual fields during the simultaneity judgment tasks. However, during the temporal order judgment task and stream/bounce perception, rapid recalibration occurred only in the central visual field. These results suggest that differences in visual processing speed based on the visual field modulate the temporal processing of audio-visual stimuli. Furthermore, these three tasks, temporal order judgment, simultaneity judgment, and stream/bounce perception, each have distinct functional characteristics for audio-visual synchrony perception. Future studies are necessary to confirm the effects of compensation regarding differences in the temporal resolution of the visual field in later cortical visual pathways on visual field differences in audio-visual temporal synchrony.

Highlights

We perceive external environments using multisensory information
In a temporal order judgment (TOJ) task, differences in the point of subjective simultaneity (PSS) between the central and peripheral visual fields (VFs) could be attributed to differences in visual latency rather than temporal resolution
In the TOJ task of Experiment 1, the PSS score indicated that the auditory stimulus was presented earlier as a visual stimulus for one to perceive subjective simultaneity in the central than in the peripheral VF condition

Summary

Introduction

We perceive external environments using multisensory information. Temporal synchrony is critical for the integration of different sensory stimuli. It can be seen that the processing speed differs between the central and peripheral VFs. The present study confirmed the effects of visual temporal resolution on audio-visual synchrony perception by manipulating the VF in which the visual stimulus was presented (i.e., eccentricity). Eccentricity-dependent audio-visual temporal processing and showed that the timing of subjective simultaneity did not differ between VFs. their study did not employ other paradigms to measure PSS nor did it measure the TBW. The differences in the effects of rapid temporal recalibration between SJ and TOJ tasks were investigated to confirm the effects of VFs on audio-visual temporal processing in this study. The process of rapid recalibration was investigated for both the VFs

Materials and methods

Results

Discussion

Conclusion