Frauke Heins^1,2, Markus Lappe^1,2; ¹University of Muenster, ²Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience

In a recent eye-tracking study, oculomotor learning in response to congruent and incongruent error signals was investigated. The error signals were derived from post-saccadic target position information and target surface feature information: an intra-saccadic shift of an object array was combined with a color swap of the objects within the array. A verbal instruction determined the relevant target feature and, hence, the target object. The saccade amplitude was adjusted such that it landed on the defined target object both in case of congruent and incongruent post-saccadic information and the adaptation magnitude reached during late-adaptation was the same. However, the aftereffects of the adaptation showed a different pattern of results. While the saccade amplitude could be easily adjusted to the current task, incongruent information induced latent adaptation or interference. To gain a better understanding of the mechanisms involved, we conducted another eye-tracking study. We induced learning with incongruent and congruent information and additionally measured the perceived location of objects. We hypothesized that the saccade amplitude would adjust such that task success is achieved and, hence, a post-saccadic reward error is reduced. In addition, we expected that an incongruent sensory error, i.e., a mismatch between the expected and actual sensory consequences of the saccade, would induce mislocalization in the direction of the sensory error. The results confirm that the saccade amplitude was adjusted to achieve task success. Further, they demonstrate that incongruent sensory information can lead to a shift in the perceived location of objects simultaneously. These results suggest that an update of the spatial target representation, which manifests in shifts in perceived location and latent learning, is caused by sensory errors. We conclude that oculomotor learning can involve both reward and sensory errors and that while the former affects saccade metrics directly, the latter changes the representation of objects in space.