PT  - JOURNAL ARTICLE
AU  - Jochem van Kempen
AU  - Gerard M. Loughnane
AU  - Daniel P. Newman
AU  - Simon P. Kelly
AU  - Alexander Thiele
AU  - Redmond G O’Connell
AU  - Mark A. Bellgrove
TI  - Behavioural and neural signatures of perceptual evidence accumulation are modulated by pupil-linked arousal
AID  - 10.1101/433060
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 433060
4099  - http://biorxiv.org/content/early/2018/10/03/433060.short
4100  - http://biorxiv.org/content/early/2018/10/03/433060.full
AB  - The timing and accuracy of perceptual decision making is exquisitely sensitive to fluctuations in arousal. Although extensive research has highlighted the role of neural evidence accumulation in forming decisions, our understanding of how arousal impacts these processes remains limited. Here we isolated electrophysiological signatures of evidence accumulation alongside signals reflecting target selection, attentional engagement and motor output and examined their modulation as a function of both tonic and phasic arousal, indexed by baseline and task-evoked pupil diameter, respectively. For both pupillometric measures, the relationship with reaction time was best described by a second-order, U-shaped, polynomial. Additionally, the two pupil measures were predictive of a unique set of EEG signatures that together represent multiple information processing steps of perceptual decision-making, including evidence accumulation. Finally, we found that behavioural variability associated with fluctuations in both tonic and phasic arousal was largely mediated by variability in evidence accumulation.