This study investigated the effect of hand movements on behavioral and electro-physiological parameters of saccade preparation. While event-related potentials were recorded in 17 subjects, they performed saccades to a visual target either together with a hand movement in the same direction, a hand movement in the opposite direction, a hand movement to a third, independent direction, or without any accompanying hand movements. Saccade latencies increased with any kind of accompanying hand movement. Both saccade and manual latencies were largest when both movements aimed at opposite directions. In contrast, saccade-related potentials indicating preparatory activity were mainly affected by hand movements in the same direction. The data suggest that concomitant hand movements interfere with saccade preparation, particularly when the two movements involve motor preparations that access the same visual stimulus. This indicates that saccade preparation is continually informed about hand movement preparation.
Uta Sailer, Florian Güldenpfennig and Thomas Eggert
Thomas Hausegger, Christian Vater and Ernst-Joachim Hossner
during saccades ( Kowler, 2011 ). Therefore, one’s gaze should be focused toward a specific location. Such a “gaze-anchoring” behavior can be seen as a strategy to monitor all relevant information regions within the visual field. For instance, in combat sports whereby the extremities are used for attack
Florian Van Halewyck, Ann Lavrysen, Oron Levin, Digby Elliott and Werner F. Helsen
Older adults traditionally adapt their discrete aiming movements, thereby traveling a larger proportion of the movement under closed-loop control. As the beneficial impact of a physically active lifestyle in older age has been described for several aspects of motor control, we compared the aiming performance of young controls to active and sedentary older adults. To additionally determine the contribution of visual feedback, aiming movements were executed with and without saccades. Results showed only sedentary older adults adopted the typical movement changes, highlighting the impact of a physically active lifestyle on manual aiming in older age. In an attempt to reveal the mechanism underlying the movement changes, evidence for an age-related decline in force control was found, which in turn resulted in an adapted aiming strategy. Finally, prohibiting saccades did not affect older adults’ performance to a greater extent, suggesting they do not rely more on visual feedback than young controls.
Miya K. Rand and George E. Stelmach
This study examined how aging compromises coordinative eye-hand movements with multiple segments. Older adults and young controls performed two-segment movements with the eyes only or with the eyes and hand together. The results showed minimal age-related changes on the initiation and execution of primary saccade during the first segment. However, the older adults showed a scaling problem of saccade velocity when hand movements were included. They were also slow in stabilizing gaze fixation to the first target. Regarding hand movements, the older adults pronouncedly increased the deceleration phase compared with the controls while fixating their gazes to the target. They also increased the intersegment interval for both eye and hand movements. Taken together, aging differentially affects various components of movements, which contributes to the slowness of overall performance.
Francesc Llorens, Daniel Sanabria, Florentino Huertas, Enrique Molina and Simon Bennett
The abrupt onset of a visual stimulus typically results in overt attentional capture, which can be quantified by saccadic eye movements. Here, we tested whether attentional capture following onset of task-irrelevant visual stimuli (new object) is reduced after a bout of intense physical exercise. A group of participants performed a visual search task in two different activity conditions: rest, without any prior effort, and effort, immediately after an acute bout of intense exercise. The results showed that participants exhibited (1) slower reaction time of the first saccade toward the target when a new object was simultaneously presented in the visual field, but only in the rest activity condition, and (2) more saccades to the new object in the rest activity condition than in the effort activity condition. We suggest that immediately after an acute bout of effort, participants improved their ability to inhibit irrelevant (distracting) stimuli.
Herbert Heuer and Wolfhard Klein
Concurrent movements of different effectors are subject to structural constraints that facilitate certain patterns of coordination but impede others. The constraints for concurrent rotations of the head and a bimanually operated steering device were explored in two experiments. To indicate structural constraints, the difference between concurrent periodic rotations in same and different directions with respect to the variable error of synchronization was used. The first experiment showed less error for rotations in same directions than for rotations in opposite directions. In the second experiment, the same result was obtained with a horizontal and a backward-tilted steering wheel. Adding gaze shifts to head oscillations increased the accuracy of synchronization but did not affect the difference between both coordination patterns. In contrast to the synchronization of head and steering device, the variable error of synchronization of gaze and steering wheel did not differ between both modes of coordination; the error was again reduced when head oscillations were added to the saccades between eccentric fixation targets. This suggests space related (or allocentric) constraints, which most likely originate from concurrent specifications of movement directions in coupled spatiotopic maps so that the specification of rotations in the same direction is facilitated in comparison to rotations in opposite directions.
Theresa L. Miyashita and Paul A. Ullucci
movement and visuomotor arm movement deficits following mild closed head injury . Brain . 2004 ; 127 : 575 – 590 . PubMed ID: 14736751 doi: 10.1093/brain/awh066 14736751 13. Heitger MH , Anderson TJ , Jones RD. Saccade sequences as markers for cerebral dysfunction following mild closed head
Marlowe Pecora, Luc Tremblay and Matthew Heath
linearly with ID Fitts , and the group mean slopes for ID Fitts /MT and ID Fitts /TAPV were both 7 ms. The ID Fitts /MT slope reported here is consistent with work involving similar width-based manipulations of ID Fitts (i.e., 3.36–4.67 bits) ( de Grosbois et al., 2015 ; Heath et al., 2011 ; for saccades
Cédrick T. Bonnet
example, if an individual wants to perform a precise saccade of 10° on the left, and if he/she sways a corresponding angle of 0.1° on the left at the same moment, he/she would need to perform a gaze shift of 9.9° and not 10° to reach the target straight with no corrective saccade. The model was called
Jacqueline Phillips, Kelly Cheever, Jamie McKeon and Ryan Tierney
ocular motor function, such as smooth pursuits, saccades, and near point of convergence (NPC), provide information in identifying athletes in need of targeted treatment. 3 , 4 Many of these tools, however, require further investigation to determine their clinical usefulness. 3 NPC measures the closest