Abstract
Vision is not passive. One role of vision is to guide action for effective interaction with the environment. However, the mechanisms influencing visuomotor performance are poorly understood. In the current study we investigated whether visuomotor performance can be altered by choline supplementation in healthy human participants. As a proxy of cholinergic activity, participant's pupil size was measured at fixed intervals after the ingestion of 2 grams choline or placebo. Seventy-five minutes after ingestion participants were tested on their accuracy and speed of computer mouse movements in a visuomotor coordination task. We found that their pupil constricted after choline administration and that their movements became more accurate but slower. Further, the amount of pupil constriction per individual predicted the improvement in accuracy. In a second experiment we investigated more closely the link between pupil size and vision-guided correction movements as a function of time. We found that pupil dynamics highlight the phases and extent to which the precision of motor responses is improved through visual feedback. These findings suggest that cholinergic activity, as manipulated with choline and probed with pupil constrictions, is linked to the speed-accuracy trade-off. We suggest that cholinergic networks in the nervous system play a central role in the coordination of actions towards visual stimuli and that pupillometry is a promising method to assess the speed-accuracy trade-off and cholinergic activity.
Meeting abstract presented at VSS 2016