Logan McIntosh¹, Robert Volcic^1,2,3; ¹New York University Abu Dhabi, ²Center for Artificial Intelligence and Robotics, New York University Abu Dhabi, ³Center for Brain and Health, New York University Abu Dhabi

Previous research has shown that when visual information about the target location is complemented by haptic information, such as grasping a nail while striking it, movements tend to be faster and more precise. However, it is unclear whether the benefits of haptic information are also seen in speeded reaching movements when the target changes location unpredictably during the actual movement, or when the actual target among multiple target locations is revealed after movement onset. In this study, participants made speeded reaching movements in various conditions of potentially predictable or unpredictable target locations to one of two physical targets, placed 30 cm away and 6.25 cm to the left and right from the midline. The target location was cued at the start at of each trial through illumination of the monitor area underneath the target. However, on trials in which target location was unpredictable, the target location changed with 50% probability to the other location shortly after the movement was initiated, triggering an on-line movement correction. Movements were completed either purely by vision or with additional haptic information provided by holding the physical target in the left location, counterbalanced across different blocks. Thus, on trials with additional haptic information, sensory information about the left target location was provided by both vision and haptics. In contrast, sensory information about the right target location was derived exclusively from vision. We found that the addition of haptic information influences movement trajectories, with further differences between movements in predictable and unpredictable target location conditions. We also found idiosyncrasies in movement trajectories, with some participants showing a repulsion effect away from the haptic target location and others showing an attraction effect. Our study shows that the availability of additional sensory information affects the planning and execution of speeded reaching movements.

Acknowledgements: We acknowledge the support of the NYUAD Center for Artificial Intelligence and Robotics and the NYUAD Center for Brain and Health, funded by Tamkeen under the NYUAD Research Institute Awards CG010 and CG012.