Long-term Memory Of Object Locations And Strabismus Angle Requires Oculomotor Proprioception

In humans, the accuracy of saccades to remembered spatial locations deteriorates linearly with the first few intervening saccades between the initial target presentation and the final saccade to the remembered target location. As the number of intervening saccades increases, the degree of deterioration decreases until it asymptotes. One explanation for the asymptote of saccadic error is that when the number of intervening saccades is low, the brain relies on a corollary discharge of the saccade to remap the retinotopic receptive field, with the error being additive with each remapping, consistent with Helmholtz's postulate[1]. The asymptote of saccadic error may be due to a switch from a retinotopic remapping process to a stable craniotopic representation which can be accessed repeatedly without concurrent increases in saccadic inaccuracy and is consistent with Sherrington's postulate[2, 3]. We hypothesized that the late, stable representation is dependent upon a proprioceptive mechanism[4].