Abstract
Tracking a moving object with smooth pursuit eye movements enhances our ability to predict an object's trajectory. Here we assessed the relationship between pursuit and hand movements and compared the efficacy of different training protocols on eye and hand movement accuracy. In a novel track-intercept task observers tracked a target moving across a screen and hit it with their index finger after it entered a "hit zone". Following brief presentation (100-300 ms), observers had to extrapolate and intercept the target at its assumed position; feedback about actual position was given after interception. We conducted three experiments with different training protocols. In each experiment, baseline pursuit (fully visible trajectory) and track-intercept task were tested on day 1 (pre-test) and day 5 (post-test). During training (days 2-4), observers either: tracked and intercepted the target (n=9, eye-hand-training), tracked but did not intercept (n=9, eye-training), or received no training (n=9). We analysed effects of training type and day on the accuracy of eye and hand movements. Manual interception accuracy improved significantly across groups, but effects were larger for the training groups than after no training. By contrast, improvements in eye movements were only observed after training and not in the control group. Interestingly, despite equal exposure to the tracking task during training, smooth pursuit was more accurate after combined eye-hand training vs. eye training. These benefits (significantly higher peak eye velocity, gain, lower position error, shorter latency) were observed in the track-intercept task and in baseline pursuit on day 5, indicating global pursuit performance improvements after eye-hand training. Eye-movement training improves the accuracy of hand movements, and engaging the hand during eye-movement training, in return, enhances smooth pursuit. These findings support the idea of shared pathways for eye-hand movement control and have implications for our understanding of transfer in perceptual-motor learning tasks.
Meeting abstract presented at VSS 2016