Spatial Orienting of Attention: Sensory Facilitation or Response Bias

摘要

Visually evoked brain potentials were recorded from young adult subjects in response to flashed target stimuli that occurred at attended (expected) or unattended spatial locations. Attention was directed to the left or right visual field by a warning cue (arrow) that designated the most probable location of the target flash, to which subjects made a speeded discriminative response. Targets presented to the expected location were found to elicit brain potentials of enhanced amplitude over the occipital scalp regions, in relation to targets at the opposite, unexpected location. The evoked potentials to attended-field targets were increased in amplitude as early as 90-100 msec post-stimulus, but the basic waveform of the response was not altered. These results support the proposal of Posner and associates that the spatial cueing and orienting of attention produces a facilitation of sensory evoked activity in the visual pathways.