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Levels of cognitive organization in human eye movements

Final Report Summary - EYELEVEL (Levels of cognitive organization in human eye movements)

Visual perception is essential for the interaction with our environment and requires various types of eye movements. Clear and stable vision is limited to the small foveal region (ca. double the size of a thumbnail) and to the time of fixations (when the eyes are relatively stable). During fast saccadic eye movements the fovea is brought from one point to another and our vision is mainly suppressed. Characteristics in the interplay of fixations and saccades as well as in brain activity have been separately investigated in relation to basic, reflexlike mechanisms (e.g. the presentation of sudden visual changes) and higher cognitive functions, such as localization and identification of objects. The EYELEVEL research project aims to further investigate these mechanisms by combining eye-tracking and magnetencephalography (MEG) during free visual exploration.

EYELEVEL contributes to a better understanding of eye movement control (in general and at the level of single fixations) and how this is related to the hierarchical cognitive organization.

It examines
1) what are the neurophysiological mechanisms and involved brain regions responsible for the distractor effect,
2) if and how can different stages of processing expressed in distinct eye movement characteristics explained by the underlying brain activity and
3) how both research lines can converge for an online probing of processing modes?

Research within the project could demonstrate that the combined measurement of eye movements and MEG is technically possible during active vision, even on the level of individual fixations. Ongoing work considers the analysis of particular mechanisms of eye movement behaviour during free visual exploration of natural images by correlating specific gaze patterns with the obtained brain activity.