Fixation-related potentials in visual search: a combined EEG and eye tracking study

Area of Science:

• Neuroscience
• Cognitive Psychology
• Visual Perception

Background:

• Understanding the neural basis of visual search is crucial for cognitive science.
• Previous research often uses controlled stimuli, limiting insights into naturalistic viewing behaviors.

Purpose of the Study:

• To investigate neural activity during free visual exploration using concurrent eye-tracking and electroencephalography (EEG).
• To identify event-related potentials (ERPs) associated with visual search and compare them across different viewing conditions.

Main Methods:

• Simultaneous recording of eye movements and EEG in participants freely searching for targets.
• Analysis of fixation-event related potentials (fERPs) and comparison with controlled replay and central presentation experiments.
• Development of a novel method to match critical properties between target and distractor conditions.

Main Results:

• A distinct sequence of fERPs (∼400 ms) was observed following each fixation during free viewing.
• This fERP sequence resembled responses from a controlled replay experiment and a central stimulus presentation experiment.
• An early ERP component (∼150 ms) differentiated targets from distractors specifically in the free-viewing condition.

Conclusions:

• The findings suggest a consistent neural replay mechanism underlying visual exploration, regardless of viewing condition.
• A novel method was developed for analyzing EEG during free eye movements, applicable to various research paradigms.
• This study advances our understanding of the neural dynamics of naturalistic visual search.