Attentional orienting and reorienting is indicated by human event-related brain potentials

We investigated event-related potential indications for the orienting towards task-irrelevant, distracting aspects of stimulation and for the subsequent reorienting towards task-related aspects of stimulation. An identical experimental protocol was run in three conditions manipulating the task relevance of the sounds. As to be expected, distractors elicited the MMN (reflecting the brain's pre-attentive change detection) in each condition (even when the sounds were ignored) and subsequent N2b and P3 (reflecting orienting towards the distractor) when the sounds were attended. A late negativity was confined to a condition in which subjects discriminating long from short sounds were distracted by task-irrelevant frequency deviations. The 'reorienting negativity' (RON) probably reflects processes in the context of reorienting towards task-relevant aspects of stimulation following distraction.