選択的注意と事象関連電位

Abstract

Negative shifts in event-related potentials (ERPs) associated with selective attention were compared between fixed and varying tone pips. The fixed and varying tones were presented with noise bursts in random order within a single sequence. In selective listening to tones varying systematically in pitch and spatial location, subjects were told in advance to expect changes in these attributes from moment to moment. If they had not expected any changes, they would not have been able to selectively track and attend those varying tones. For selective attention to fixed tones, no such preliminary instruction was required. Fronto-centrally dominant negative shifts of ERPs, beginning around 80 ms post-stimulus, were observed when the eliciting tones were selectively attended. The developing phase of these negative shifts followed a similar pattern for the fixed and varying tones although the negative shift to varying tones declined a little earlier (by about 25 ms in grand average waveform) than it did to the fixed tones. These results indicated that expectations based on contextual information from prior stimuli can play an important role in early input selection. Some models of attention which emphasize the role of such expectations were discussed.