Extraretinal signals in perception and action – EPA

Vision is more than the processing of retinal information. Moving our eyes to different parts of the scene is crucial to the collection of the high-acuity visual information that is the basis of vision. However, eye movements also pose some interesting challenges to vision, because each movement changes the retinal location of objects. Because retinal locations constitute the raw input to the visual system, some kind of compensation must occur for these displacements to be differentiated from real object movement and in order to localize objects in a stable visual reference frame; in other words, to ensure visual stability. Furthermore, because the strength of the eye muscles can vary with growth and fatigue, and because eye movements are inherently variable a constant recalibration of the relationship between perception and action must take place. Both visual stability and adapted motor behavior may be achieved through the monitoring of self-movement. Self-movement information is a non-retinal, or extraretinal, signal that nevertheless may contribute to visual perception. Information about how one’s own eyes have moved can be combined with sensory information to distinguish self from real-object movement. Such information can also be used to adapt future behavior if previous movement plans were unsuccessful. The current project is a fundamental research approach combining behavioral methods, psychophysics and transcranial magnetic stimulation (TMS). Its goal is to examine the influence of extraretinal information on visual perception and motor behavior, with a focus on the following questions:
• How is information about one’s own eye movements integrated with visual information and how does this integration affect perception and motor behavior?
• How does this integration develop in infancy?
• How does this integration fare in schizophrenia?
• What brain areas might sub-tend this integration?