Early visual modulation and selection predict saccadic timing during visual search: An ERP study
Ryan V Ringer1, Carly J Leonard1
1Department of Psychology, University of Colorado Denver, Denver, Colorado, USA.
Psychophysiology
|October 26, 2024
Summary
Delays in saccadic eye movements, crucial for vision, occur when the visual system is overwhelmed. Vigorous information accumulation, reflected by P1 amplitude, and weak selection, shown by N1 amplitude, contribute to slower saccade decisions.
Area of Science:
- Neuroscience
- Cognitive Science
- Visual Perception
Background:
- Saccadic eye movements are essential for visual exploration.
- The precise roles of information accumulation and selection in saccadic timing remain unclear.
Purpose of the Study:
- To investigate how early electroencephalography (EEG) amplitudes, specifically P1 and N1 event-related potentials (ERPs), relate to saccadic timing.
- To determine if P1 reflects information accumulation and N1 reflects selection strength in saccadic decision-making.
Main Methods:
- Participants performed a visual search task while EEG and electrooculography (EOG) were recorded.
- Posterior cortical activity was analyzed between display onset and saccade initiation.
- Trials were binned into fast, middle, and slow saccade groups based on timing.
Main Results:
- The N1 response was smallest in the slow saccade group, indicating weaker selection.
- The P1 response was largest in the slow saccade group, suggesting more vigorous information accumulation.
- These findings suggest that saccadic timing is influenced by the interplay between information accumulation and selection.
Conclusions:
- Saccadic delays can arise from an overloaded visual system, prolonging the decision-making process.
- This study integrates models of eye movement control by highlighting the combined roles of information accrual and selection.
