Larger Head Displacement to Optic Flow Presented in the Lower Visual Field

Area of Science:

• Human postural control
• Visual perception
• Self-motion simulation

Background:

• Postural adjustments are often triggered by optic flow simulating self-motion.
• Previous research suggests human postural control relies heavily on visual input from the lower visual field.
• The specific impact of optic flow's vertical location on postural responses remains under-investigated.

Purpose of the Study:

• To investigate whether optic flow presented in the lower visual field elicits stronger postural responses compared to the upper visual field.
• To quantify differences in head displacement and vection strength based on optic flow location.

Main Methods:

• Participants experienced expanding or contracting optic flow presented in the upper, lower, or full visual fields using a head-mounted display (Oculus Rift).
• Measurements included head displacement and subjective vection strength.
• Experimental conditions varied optic flow presentation across different visual field locations.

Main Results:

• Head displacement was significantly larger with optic flow in the full and lower visual fields compared to the upper visual field, particularly during the initial presentation of contracting optic flow.
• Vection strength was greatest in the full visual field and lowest in the upper visual field.
• These results indicate a superiority of the lower visual field in modulating postural responses and vection.

Conclusions:

• The findings support the hypothesis of lower visual field superiority in human postural control and self-motion perception.
• Ecologically relevant visual information, particularly from the lower visual field, plays a crucial role in maintaining balance and sensing self-motion.
• Optic flow's vertical location is a critical factor influencing postural stability and the perception of self-motion.