A high- temporal resolution, high brightness 3D projector to study visual perception, attention & eye movements

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Motion perception is crucial for many daily activities such as walking in a crowded environment, practicing a sport, crossing a busy street, driving and watching TV. However, this visual function is considerably affected with aging, which can affect the ability of older adults to accomplish basic daily tasks, and thereby gradually affect their autonomy. It is important to identify the underlying causes of this age-related visual decline in order to develop interventions to optimise the autonomy of older adults. However, age-related visual declines might not be due to motion perception per se. We have recently found that the amount of light detected by the photoreceptors of healthy older adults is approximately 10 times less than young adults. Given that motion perception largely depends on luminance intensity (i.e., on the amount of light absorbed by photoreceptors), a large component of age-related decline in motion perception may be due to a lower detection of light by photoreceptors. An efficient method to neutralize the impact of different levels of light detection is to present the stimulus at a brightness so high that visual performance is optimal. Thus, the new equipment that will be acquired (i.e., high brightness, high temporal resolution 3D projector) will enable us to display moving stimuli at high brightness so that visual performance is optimised and the amount of light absorbed by photoreceptors has a negligible impact on visual performance. The main objective of the current research program is to investigate the underlying mechanisms involved in age-related changes in healthy aging. We will investigate 1) to what extent reduction in the amount of light detected by photoreceptors accounts for these changes and 2) how different visual functions change taking this lowered visibility into consideration by presenting testing visual stimuli at high brightness, thus neutralizing this age-related visibility effect. To address these topics from a new perspective, a unique experimental setup will be acquired by combining two pieces of infrastructure enabling to probe the visual system at elevated temporal frequencies using non-invasive experimental paradigms. The first is a real-time projector design for psychophysics (PROPixx/HB) with a high temporal resolution (1440 Hz) and high brightness, allowing us to present visual stimuli with high temporal precision at high brightness. The second piece of equipment is a high-resolution video-based eye tracking setup that allows high temporal and spatial recording precision of eye movements. The requested infrastructure will create a unique psychophysical experimental setup. The high temporal resolution, high brightness display combined with a cutting-edge eye tracker will enable to probe the visual system like never before and provide new insights on the impact of aging on motion perception.