To examine whether anticipatory attention or expectancy is a cognitive process that is automatic or requires conscious control, we employed a paired-stimulus event-related potential (ERP) paradigm during the transition to sleep. The slow negative ERP wave observed between two successive stimuli, the Contingent Negative Variation (CNV), reflects attention and expectancy to the second stimulus....
During the waking state, a late component of the auditory event-related potential, P300, is elicited when subjects detect a rare 'target' stimulus. It is usually not elicited when subjects either ignore or fail to detect the stimulus. The presence of P300 is therefore thought to reflect conscious processing of the stimulus. Since P300 has been shown to be an attention-dependent cognitive...
STUDY OBJECTIVES: A cognitive evoked potential, labelled "P300," is elicited when an observer attends to and detects an infrequently delivered "target" stimulus. It is not typically present if the target is ignored or undetected. P300 is therefore thought to reflect some aspect of consciousness of the stimulus. There has been much controversy concerning whether P300 can be recorded in sleep, a...