Neural systems of visual target detection: Human event-related potential studies

Organisms must identify and preferentially process relevant environmental events. This cognitive process is known as selective attention. Both human and animal studies indicate that selective attention is one of the regulatory functions of the anterior brain. Single unit studies in the monkey suggest that anterior regulatory networks interact with posterior networks holding the representation of a presented stimulus in target detection. Event-related potential have been used extensively in the study of human attention. This paper describes three experiments which use the ERP to investigate anterior-posterior neural interactions in visual target detection.; Experiment 1 uses a visual oddball paradigm and a high-density ERP recording array to study the spatio-temporal characteristics of the scalp electrical field index of target detection. Experiment 1 also separates effects of stimulus novelty and subject arousal from the operation of target detection. Experiment 2 separates the operation of target detection from the organization of a specific response by demonstrating stability of the electrophysiological target detection effect across response type (silent counting vs. button pressing). Experiment 3 associates the selective attention operation with specific representational networks by manipulating selection criteria. In one task target detection is based upon location, requiring information from the dorsal spatial location pathway. In the other task target detection is based upon object features, requiring information from the ventral object recognition pathway. The target detection effect changes its spatio-temporal characteristics across selection parameter, indicating interaction of anterior selective attention networks with different posterior stimulus representation networks.