Rolheiser, Tyler Murray
The contribution of ventral stream information to the variability of movement has been the focus of much attention, and has provided numerous researchers with conflicting results. These results have been obtained through the use of discrete pointing movements, and as such, do not offer any explanation regarding how ventral stream information contributes to movement variability over time. The present study examined the contribution of ventral stream information to movement variability in three tasks: Hand-only movement, eye-only movement, and an eye-hand coordinated task. Participants performed a continuous reciprocal tapping task to two point-of-light targets for 10 seconds. The targets were visible for the first five seconds, at which point vision of both the targets and the limb was occluded by liquid crystal goggles. Movement variability was similar in all conditions for the initial 5-second interval. The no-vision condition (final 5-seconds) can be summarized as follows: Ventral stream information contributed to an initial significant increase in variability across motor systems, though the different motor systems were able to preserve ventral information integrity differently. The results of these studies can be attributed to the behavioural and cognitive mechanisms that underlie the saccadic and manual motor systems.