title: N400 amplitude reduction correlates with an increase in pupil size.
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 may provide new insights into the suggested link between human high-level cognitive function and activity of the LC-NE system.
authors: ESRC Centre for Research on Bilingualism in Theory and Practice, Bangor University Bangor, UK.
authors: Jan Rouke
authors: JR
authors: Kuipers
authors: Guillaume
authors: G
authors: Thierry