Presaccadic EEG activity predicts visual saliency in free-viewing contour integration

Area of Science:

• Neuroscience
• Cognitive Science
• Visual Perception

Background:

• The human visual system is drawn to salient stimuli when viewing a scene.
• Understanding the neural mechanisms guiding visual attention is crucial for cognitive science.
• Previous models can quantify visual saliency at fixation points.

Purpose of the Study:

• To identify brain signals that control the process of visual attention to salient stimuli.
• To investigate the relationship between visual saliency and electroencephalography (EEG) signals during a visual search task.
• To explore the role of attentional effort in selecting saccade targets based on their saliency.

Main Methods:

• Coregistered eye tracking and electroencephalography (EEG) were used to record brain activity.
• A contour integration task with Gabor elements was employed to manipulate visual saliency.
• Generalized additive mixed modeling (GAMM) was applied to saccade-related EEG epochs to separate salience-related signals from eye movement responses.

Main Results:

• Lower amplitude of presaccadic EEG activity was observed when the next fixation location had high visual saliency.
• Higher attentional effort, reflected by presaccadic EEG activity, was needed for selecting less salient saccade targets.
• This effect was more pronounced in conditions with a visible contour compared to contour-absent conditions.

Conclusions:

• Presaccadic EEG activity may reflect bottom-up influences on saccade guidance.
• The findings suggest that visual saliency modulates attentional effort during visual exploration.
• Generalized additive mixed modeling (GAMM) is a valuable tool for analyzing coregistered EEG and eye-movement data.