What renders a saccade target relevant?

Basic data for this project

Description

Humans continuously shift their gaze using saccade eye movements, each time choosing a different object or region of the visual field for high resolution visual processing. The mechanisms why we choose one particular target over another are not yet fully understood. Information about these underlying oculomotor decisions can be revealed by the fact where people look, when they move their eyes as well as the kinematics of the eye movement itself. All of these aspects of oculomotor control can be influenced when targets are rendered relevant by means of reward as has been shown by variety of studies. The combination of information about low-level stimulus features and reward for oculomotor control can best be explained in terms of a priority map. Characteristics of such a map have been described for several neural sites along the oculomotor network. However, in recent years, it became more and more clear that receiving a monetary reward for a saccade eye movement can be considered an artificial scenario, because saccades do usually not provide us with reward, but they provide us with information for visual perception. Consequently, recent studies have focused on how eye movements are affected by their perceptual consequences.Building on the priority map concept, the current project focusses on the question whether and how our eye movements are affected by their perceptual consequences, thus by what we are about to see. We suggest that image content, similarly as information about reward, is represented in a priority map. Throughout four work packages, we will investigate how salience and relevance interact, we aim to uncover the process by which image content might be rendered relevant, we will investigate whether image content and relevance by reward affect oculomotor behavior similarly or via distinct mechanisms, and we will shed light on how the image content of the currently fixated target influences the planning of the next saccade. These findings will help to understand the processes by which the visual system assigns priority to targets in a visual scene.