Examining Visual Versus Kinesthetic Temporal Accuracy and Variability

• Arianna Eimont, Neuroscience, University of Delaware

• Jennifer Semrau, Kinesiology and Applied Physiology, University of Delaware

Every day, we use sensory information (vision, proprioception) from our world to guide our actions. Proprioception is knowing where one’s limbs are in space and is critical for movement. To process external sensory information, it must travel from sensory receptors to the brain. For proprioception, these delays range from 50-60 milliseconds while visual delays range from 100-120 milliseconds. While delays for proprioceptive information are shorter, this system is less precise due to the integration of information from multiple sources needed to create an estimate of limb location in space. Visual monitoring of movement-based information is more precise due to higher spatial and temporal resolution. To determine if visual information has greater temporal accuracy and lower variability than proprioceptive information, we used a robotic timing task to evaluate visual and proprioceptive reaction times. We used a Kinarm robotic exoskeleton to test 15 control participants (25.3 ± 4.3) on two robotic measurements to examine the average reaction time when participants relied only on visual (Visual Timing Task) or proprioceptive information (Proprioceptive Timing Task). The Visual Timing Task consisted of a white circle (1 cm diameter) traveling on an invisible circular path that passes through a single fixed target (2 cm diameter). The participant was instructed to press a handheld button when the circle reached the center of the target. Similarly, the Proprioceptive Timing Task consisted of a fixed target on an invisible circular path; however, now the robotic exoskeleton passively moves the participant’s arm without any visual feedback. Participants were instructed to press the button when they felt that their fingertips reached the center of the target. We observed that control participants had more accurate and less variable reaction times in the Visual Timing Task compared to the Proprioceptive Timing Task (p < 0.01). Overall, we observed that the visual system is more precise at detecting temporal changes in sensory information than the proprioceptive system, confirming our hypothesis.