Attentive and pre-attentive periodicity analysis in auditory memory: an event-related brain potential study.

In an event-related potential (ERP) study we presented human subjects with streams of repetitive white noise (semi-periodic noise) under attend and ignore conditions to investigate whether the perception of the periodicity with short cycle-lengths is due to lower level, pre-attentive sensory memory processing or higher level, attentive working memory processing. The ERPs of both conditions reveal N1-like deflections that are time locked on the semi-periodic noise suggesting that the processing of the periodicity is due to a pre-attentive rather than an attentive process. The topography of the deflections suggests that its generators are located in the supratemporal plane. Additionally, the ERPs elicited by infrequent disruptions in the periodicity show differences between the conditions suggesting that the detection of disruptions in periodicity is facilitated by attention.