Inter- and intra-individual coupling between pupillary, electrophysiological, and behavioral responses in a visual...

Area of Science:

• Cognitive Neuroscience
• Neurophysiology
• Psychology

Background:

• The P3b event-related potential component's generators are poorly understood.
• The locus-coeruleus norepinephrine (LC-NE) system is hypothesized to trigger P3b.
• Pupil dilation correlates with LC activity, suggesting it as a proxy for LC-NE function.

Purpose of the Study:

• To investigate the trial-to-trial relationship between pupillary dilation response (PDR) and P3b.
• To differentiate between inter-individual and intra-individual contributions to the PDR-P3b coupling.
• To test the LC-P3b hypothesis by examining PDR and P3b in relation to LC-NE activity.

Main Methods:

• Simultaneous recording of electroencephalography (EEG) for P3b and pupillometry for PDR.
• Analysis of inter-individual (between-participant) and intra-individual (within-participant) relationships.
• Examination of baseline pupil dilation and phasic PDR in relation to P3b amplitude and latency.

Main Results:

• No significant trial-to-trial relationship was found between PDR and P3b.
• Neither inter-individual nor intra-individual PDR predicted P3b.
• Baseline pupil dilation, but not phasic PDR, predicted P3b amplitude.
• Both PDR and P3b independently predicted response time variability.

Conclusions:

• The findings do not support a direct phasic LC-NE-driven P3b mechanism via PDR.
• Baseline pupil dilation may reflect a different aspect of LC-NE modulation influencing P3b.
• Both PDR and P3b contribute independently to behavioral variability, suggesting distinct underlying processes.