Gaze control during reaching is flexibly modulated to optimize task outcome

When reaching for an object with the hand, the gaze is usually directed at the target. In a laboratory setting, fixation is strongly maintained at the reach target until the reaching is completed, a phenomenon known as "gaze-anchoring". While conventional accounts of such tight eye-hand coordination have often emphasized the internal synergetic linkage between both motor systems, more recent optimal control theories regard motor coordination as the adaptive solution to task requirements. We here investigated to what degree gaze control during reaching is modulated by task demands. We adopted a gaze-anchoring paradigm in which participants had to reach for a target location. During the reach, they additionally had to make a saccadic eye movement to a salient visual cue presented at locations other than the target. We manipulated the task demands by independently changing reward contingencies for saccade reaction time (RT) and reaching accuracy. On average, both saccade RTs and reach error varied systematically with reward condition, with reach accuracy improving when the saccade was delayed. The distribution of the saccade RTs showed two types of eye movements: fast saccades with short RTs, and voluntary saccade with longer RTs. Increased reward for high reach accuracy reduced the probability of reflexive fast saccades, but left their latency unchanged. The results suggest that gaze-anchoring acts through a suppression of fast saccades, a mechanism that can be adaptively adjusted to the current task demands.

Functional inhibition across a visuomotor communication channel coordinates looking and reaching

Understanding how natural behaviors are controlled depends on understanding the neural mechanisms of multiregional communication. Eye-hand coordination, a natural behavior shared by primates, is controlled by the posterior parietal cortex (PPC), a brain structure that expanded substantially in primate evolution. Here, we show that neurons within the saccade and reach regions within PPC communicate over a visuomotor channel to coordinate looking and reaching. During gaze-anchoring behavior, when saccades are transiently-inhibited by coordinated reaches, PPC neuron firing rates covary with beta-frequency (15-25 Hz) neuronal coherence. Decreases in parietal saccade neuron spiking correlated with gaze-anchoring behavior when the channel was “open” and not “closed”. Functional inhibition across beta-frequency-coherent communication channels may be a general mechanism for flexibly coordinating our natural behavior.One Sentence SummaryInhibitory communication through a visuomotor channel mediates the coordination of eye and hand movements.

A critical analysis of the functional parameters of the quiet eye using immersive virtual reality

Directing ocular fixations towards a target assists the planning and control of visually-guided actions. In far aiming tasks, the quiet eye, an instance of pre-movement gaze anchoring, has been extensively studied as a key performance variable. However, theories of quiet eye are yet to establish the exact functional role of the location and duration of the fixation. The present work used immersive virtual reality to manipulate key parameters of the quiet eye – location (experiment 1) and duration (experiment 2) – to test competing theoretical predictions about their importance. Across two pre-registered experiments, novice participants (n=127) completed a series of golf putts while their eye movements, putting accuracy, and putting kinematics were recorded. In experiment 1, participants’ pre-movement fixation was cued to locations on the ball, near the ball, and far from the ball. In experiment 2, long and short quiet eye durations were induced using auditory tones as cues to movement phases. Linear mixed effects models indicated that manipulations of location and duration had little effect on performance or movement kinematics. The findings suggest that, for novices, the spatial and temporal parameters of the final fixation may not be critical for movement pre-programming and may instead reflect attentional control or movement inhibition functions.

Peripheral Vision in Martial Arts Experts: The Cost-Dependent Anchoring of Gaze

Research on martial arts has suggested that gaze anchoring is functional for optimizing the use of peripheral visual information. The current study predicted that the height of gaze anchoring on the opponent’s body would depend on the potential attacking locations that need to be monitored. To test this prediction, the authors compared high-level athletes in kung fu (Qwan Ki Do), who attack with their arms and legs, with Tae Kwon Do fighters, who attack mostly with their legs. As predicted, the results show that Qwan Ki Do athletes anchor their gaze higher than Tae Kwon Do athletes do before and even during the first attack. In addition, gaze anchoring seems to depend on 3 factors: the particulars of the evolving situation, crucial cues, and specific visual costs (especially suppressed information pickup during saccades). These 3 factors should be considered in future studies on gaze behavior in sports to find the most functional, that is, cost-benefit-optimized, gaze pattern.

Examining the functionality of peripheral vision

In sports, it is important not only to locate gaze on the right location to utilize the high acuity of foveal vision, but also to attend to other objects in the environment without looking directly at them, accordingly, using peripheral vision. Peripheral vision becomes especially important if, for example, the processing of information from more than one location (e.g. players) is decisive in making accurate decisions. Since such decisions generally must be made under high spatio-temporal demands, costly eye-movements might be advantageously avoided by using peripheral vision for information pick-up from multiple cues. In a series of studies, we aimed to translate the demands found in sports and to investigate the functionality of peripheral vision in a well-controlled experimental paradigm, the multiple object tracking (MOT) task. MOT was implemented in a dual task, along with an additional event-detection task. The present article first presents an overview of sport-specific studies focusing on the functionality of peripheral vision and following, summarizes a series of three published MOT studies. These studies show that peripheral vision is used for simultaneous target monitoring and target-change detection and that visual and attentional demands affect gaze anchoring and change-detection rates. Results also reveal a dysfunctionality of saccades, and further suggest an event- and distance-optimized gaze-anchoring position. In the final portion of this article, we derive specific applications for future sports-specific research. Specifically, we suggest to: (a) use dual-task situations in sport-specific settings, such as monitoring multiple players in soccer and playing a pass at specific moments, (b) investigate the costs of saccades in sports situations with high spatio-temporal demands, as in martial arts, and finally, (c) manipulate attentional and visual demands. For each of these avenues of research, we sketch sports-specific experiments currently being conducted in our research group.

Examining the functionality of peripheral vision: From fundamental understandings to applied sport science

In sports, it is important not only to locate gaze on the right location to utilize the high acuity of foveal vision, but also to attend to other objects in the environment without looking directly at them, accordingly, using peripheral vision. Peripheral vision becomes especially important if, for example, the processing of information from more than one location (e.g. players) is decisive in making accurate decisions. Since such decisions generally must be made under high spatio-temporal demands, costly eye-movements might be advantageously avoided by using peripheral vision for information pick-up from multiple cues. In a series of studies, we aimed to translate the demands found in sports and to investigate the functionality of peripheral vision in a well-controlled experimental paradigm, the multiple object tracking (MOT) task. MOT was implemented in a dual task, along with an additional event-detection task. The present article first presents an overview of sport-specific studies focusing on the functionality of peripheral vision and following, summarizes a series of three published MOT studies. These studies show that peripheral vision is used for simultaneous target monitoring and target-change detection and that visual and attentional demands affect gaze anchoring and change-detection rates. Results also reveal a dysfunctionality of saccades, and further suggest an event- and distance-optimized gaze-anchoring position. In the final portion of this article, we derive specific applications for future sports-specific research. Specifically, we suggest to: (a) use dual-task situations in sport-specific settings, such as monitoring multiple players in soccer and playing a pass at specific moments, (b) investigate the costs of saccades in sports situations with high spatio-temporal demands, as in martial arts, and finally, (c) manipulate attentional and visual demands. For each of these avenues of research, we sketch sports-specific experiments currently being conducted in our research group.