Biology subjects

Schroeger, A.

Publications and source records attributed to Schroeger, A..

4 recordsLinked to original sources

bioRxiv2025

Adaptive Eye Movement Behavior for Actions in Younger and Older Adults

Humans typically combine eye and head movements to visually track and interact with moving objects. If the objects trajectory can be predicted, humans can shift gaze to the anticipated objects future location. For instance, when hitting a moving ball, people predictively look at the balls bouncing location, allowing them to overcome sensorimotor delays that would otherwise limit visual information uptake from that position. Such delays become pronounced with healthy aging, which might drive a behavioral shift towards stronger reliance on predictive gaze allocation to future positions of interest during visuomotor tasks. To investigate this, we examined gaze and hand movements of older and younger adults who played an iPad-based version of the game Pong against an automated opponent. Participants moved a paddle of two different sizes with their finger to intercept a ball moving in two speeds and bouncing off the side walls. We hypothesized that aging would lead to earlier gaze shifts to positions of interest, such as to the final wall bounce location before the ball moved toward the participants paddle, and to their own paddle around the moment of interception. As expected, both age groups intercepted fewer balls when using smaller paddles. Contrary to our hypothesis, older participants looked later than younger adults to the final wall bounce. However, they shifted their gaze earlier to their own paddle before interception, especially at the beginning of the experiment. This suggests that aging enhances predictive gaze shifts related to the immediate action. While gaze allocation patterns largely overlap between older and younger adults, aging specifically leads to adaptive eye movements just before interacting with the environment.

neuroscience↗

bioRxiv2025

Spatiotemporal biases in localization and interception: common underlying mechanisms?

Human perception of space, time and motion is subject to several biases. Lab studies showed such effects in psychophysical judgements of location, but also in action-tasks, like predicting motion and intercepting. Given that similar underlying processes have been proposed for some of these biases, we tested for a shared mechanism by correlating them across observers. Using the classical implied motion sequence, participants either indicated the remembered location of an intermittently presented dot consistently moving from one location to the next, or intercepted a predicted future location of the same intermittently presented dot. We examined whether the errors in those tasks are associated by correlating i) the overall amount of overshooting, and ii) the effect of temporal manipulations of the jump duration on these biases across participants. We found two medium correlations indicating that these two biases are indeed related to each other. Participants who show a larger effect in one task also show a larger effect in the other task, and participants with larger proneness to temporal features show them consistently across both tasks. This suggests a shared underlying mechanism, and theoretical implications are discussed.

neuroscience↗

bioRxiv2024

Keeping Your Eye, Head, and Hand on the Ball: Rapidly Orchestrated Visuomotor Behavior in a Continuous Action Task

In everyday life, we must adapt our behavior to a continuous stream of tasks and time motor responses and periods of resting accordingly. To mimic these challenges, we used a continuous interception computer game (Pong) on an iPad. This allowed us to measure the coordination of eye, hand, and head movements during natural sequential behavior while maintaining the benefits of experimental control. Participants intercepted a moving ball by sliding a paddle at the bottom of the screen so that the ball bounced back and moved toward the computerized opponent. We tested i) how participants adapted their eye, hand, and head movements to this dynamic, continuous task, ii) whether these adaptations are related to interception performance, and iii) how their behavior changed under different conditions and iv) over time. We showed that all movements are carefully adapted to the upcoming action. Pursuit eye movements provide crucial motion information and are emphasized shortly before participants must act; a strategy associated with better performance. Participants also increasingly used pursuit eye movements under more difficult conditions (fast targets and small paddles). Saccades, blinks, and head movements, which would lead to information loss, are minimized at critical times of interception. These strategic patterns are intuitively established and maintained over time and across manipulations. We conclude that humans carefully orchestrate their full repertoire of movements to aid performance and finely adjust them to the changing demands of our environment.

neuroscience↗

bioRxiv2022

On the Mechanisms of Audio-Visual Integration for Manual Interception

Natural movements, such as catching a ball or capturing prey, typically involve multiple senses. Yet, laboratory studies on human movements commonly focus solely on vision and ignore sound. Here we ask how visual and auditory signals are integrated to guide interceptive movements. Human observers tracked the brief launch of a simulated baseball, randomly paired with batting sounds of varying intensities, and made a quick pointing movement at the ball. Movement endpoints revealed systematic overestimation of target speed when ball launch was paired with a loud versus a quiet sound, even though sound was never informative. This effect was modulated by the availability of visual information: sounds biased interception when ball presentation time was short. Continuous eye movements uncovered that sound affected interception within 125 ms of ball launch and revealed a correction of the sound-induced bias when more visual information was available. Our findings suggest that auditory and visual signals are integrated to guide interception and that this integration process must occur early at a site that receives auditory and visual signals within an ultrashort timespan.

neuroscience↗