AUTHOR=Kuipers Jan Rouke , Thierry Guillaume 

TITLE=N400 Amplitude Reduction Correlates with an Increase in Pupil Size

JOURNAL=Frontiers in Human Neuroscience

VOLUME=volume 5 - 2011

YEAR=2011

URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2011.00061

DOI=10.3389/fnhum.2011.00061

ISSN=1662-5161

ABSTRACT=Pupil dilation is classically associated with increase in cognitive load in humans. Here, we studied the potential link between human pupil dilation and meaning integration effort as indexed by event-related brain potentials (ERPs). We recorded pupil size variation and ERPs simultaneously while participants were presented with matching or unrelated picture-word pairs. Whilst relatedness in meaning between spoken words and pictures typically modulated ERPs, pupil size was also affected quickly after picture onset. Moreover, during the time-window associated with meaning integration, greater pupil dilation correlated with less negative N400 amplitudes elicited by unrelated pictures. Since pupil dilation has been linked to activity of the Locus Coeruleus-Norepinephrine (LC-NE) system, these findings provide new insights into the suggested link between human high-level cognitive function and activity of the LC-NE system.