Abstract
It has been suggested that the N200 event-related potential (ERP) component is involved in focusing spatial attention onto a target location (Luck & Hillyard (1994), Psychophysiology 31: 291–308). Here, we demonstrate that the latency of this component correlates with behaviorally measured attentional shift time.
We measured attentional shift time on individual trials using our previously developed method (Carlson et al. (2007). Journal of Vision 6 (12):6). We recorded scalp ERPs while observers monitored an array of running clocks; one of these clocks was exogenously cued after a variable delay. After each trial, observers reported what the time on that clock was when it was cued. The difference between the reported and veridical time was taken as a measure of attentional shift time for that trial.
Critically, there was no a priori difference between trials: aside from varying when and which clock was cued, all trials were identical. ERP recordings were sorted a posteriori by the measured attentional shift time on each trial. The data showed a significant positive linear correlation between the latency of the N200 ERP component, recorded at POz, and the behavioral measure of attentional shift time.
Our results corroborate previous evidence that the N200 ERP component is involved in shifting visual attention, and also demonstrate a direct link between variability in a neuronal measure (N200 latency) and behavior.