The development of covert orienting:  Relation to central attention status

Infants move visual attention in space without overtly moving their eyes. This is demonstrated in a spatial cueing procedure in which a cue occurs in one location, and a target occurs in the same location or a different location. The reaction time to move the eyes toward the target differs depending on the cue-target relation. A target in the same location of the cue facilitates localization of the target ("faciliation") and the cue and target in different locations results in target localization at similar times as if no cue were present. However, if the time between the cue and target is lengthened, a target presented in the same location of the cue attenuates target localization ("inhibition of return").

In several studies I have shown that the spatial cueing effects have corresponding changes in brain areas. This is studied by recording event-related potentials in EEG. The size of the ERP component occurring about 200 ms after target onset is larger for the cue-target shown in the same location. Cortical source analysis of the ERP component has localized this component to areas of the extrastriate cortex and the fusiform gyrus. This suggest that the brain areas are involved in spatial attention, and that the enhancement of the brain area is partially responsible for the behavioral effects.

The purpose of the current study is to examine the relation of these spatial cueing effects to central attention. The level of sustained attention can be assessed by measuring heart rate changes (HR deceleration) occurring to the central stimulus. I expect that when children are attending to the central stimulus that the infant's responsiveness to any stimulus is enhanced. Thus I expect to find the spatial cueing effects (facilitation, inhibition of return) to be largest when sustained attention to the central stimulus is occurring. This experiment also will use cortical source localization of the ERP effects and will show how attention to the central stimulus affects brain areas known to be important in the development of infant spatial attention.