ИСТИНА

Selective and rapid information processing within multiple sensory streams is crucial for adaptive behaviour. Event-related potential (ERP) studies have shown that top-down attentional modulation of relevant neural representations may evoke ERP voltage shifts within the 100-200 ms time window (Ross et al., Cereb. Cortex, 2010; Näätänen et al., Psychophysiology, 2011). Most of the studies in the field dealt with forced attentional manipulations, while the present study was focused on ERP correlates of spontaneous attentional lapses. We hypothesized that a positive ERP shift similar to the rejection positivity (Alho et al., Electroen. Clin. Neuro., 1987; Degerman et al., Eur. J. Neurosci., 2008) may be present during spontaneous failures to appropriately identify stimuli. The auditory condensation task was used: four target auditory stimuli that differed in two independent features were presented randomly with equal probability. Control procedures ensured that each of the stimulus features could be easily discriminated by all participants. Participants were instructed to respond to each stimulus by pressing one of the two buttons according to a rule based on stimulus feature conjunction, which is a much more demanding task compared with singe feature discrimination. The ERP within the P2 peak time window (150-200 ms) was shifted positively preceding failed responses (errors and response omissions) compared with correct responses. This effect resembles the rejection positivity and supports the hypothesis that information processing is reduced preceding erroneous responses and omissions; this is likely related to misallocation of attention due to competition between the task execution and other mental processes.