Abstract
Despite the absence of retinal input within the physiological blindspot, perceptual filling of the blindspot has been consistently shown; suggesting visual perception can exist without retinal drive. Moreover, motor output does not require conscious awareness of visual input (Binsted et al. 2007). In the present investigation, two experiments were conducted to examine if the motor system has access to unconscious input from the blindspot: one examining how objects presented in the blindspot could modulate motor output (i.e. pointing) and a second examining the cortically evoked potentials associated with such subconscious inputs. In both experiments, the blindspot of the right eye was mapped using a modified protocol developed by Araragi & Nakamizo (2008). In E1 subjects pointed to objects presented either in the blindspot or outside of it (no target trials served as a control); if they saw no target they were instructed to guess. In E2 we performed a visual detection task under similar conditions while recording EEG (Brainvision DC, 64ch). Both endpoint position and variability was sensitive to the occurrence and position of a target. EEG analyses revealed deflections at visual and parietal sites (O1, PO3 and P3) independent of targets perception, but varying as a function of distance from blindspot centroid. Thus, despite the absence of conscious percept due to subthreshold retinal input, visuomotor pathways can use target location information to plan and execute actions.Acknowledgments: NSERC