Abstract
The superior hemiretina contains a greater density of retinal ganglion cells than the inferior. Prior work has proposed a link between this vertical retinal asymmetry and the increased effectiveness of reaching movements performed in the lower-visual field (loVF, i.e., projecting to the superior hemiretina) when compared to their upper-visual field (upVF) counterparts (Rossit et al., 2013). In turn, reaches guided by binocular vision are more accurate than their monocular counterparts and is a result attributed to binocular cues optimizing response planning and online limb corrections. The goal of the present study was to examine whether putative differences in loVF and upVF reaches are influenced by the presence of binocular visual cues during movement planning and control. Participants completed reaching responses to illuminated targets positioned in the 3D picture plane. Participants fixated on one of two different locations allowing targets to be presented in the loVF and upVF. Separate groups of participants were provided vision during response planning and control (i.e., closed-loop condition: CL), or during response planning only (i.e., open-loop condition: OL). Both groups completed binocular and monocular vision trials. As expected, CL reaches and binocular trials were more accurate than OL reaches and monocular trials, respectively. Detailed analyses of reaching trajectories (i.e., 10% through 100% of MT) indicated that CL binocular trials produced greater spatial variability in the primary movement axis than CL monocular trials or OL (i.e., binocular or monocular) trials. However, our results did not yield evidence that trajectory control was influenced by our visual field manipulation (i.e., null main effects and interactions, all Fs < 1). Accordingly, our results provide no evidence that binocular cues optimize a vertical visual field asymmetry for online trajectory amendments.
Meeting abstract presented at VSS 2017