Eimer M, Schröger E
Institut für Psychologie, Universität München, Germany.
Electroencephalogr Clin Neurophysiol. 1995 Feb;94(2):115-28. doi: 10.1016/0013-4694(94)00230-i.
Event-related potentials (ERPs) were recorded to visual and auditory stimuli in a situation where subjects were required to attend selectively to the left or right side for an entire experimental block and to detect occasional target stimuli at attended locations. Stimuli were presented randomly at attended and unattended locations. In exp. 1, visual and auditory stimuli were presented in separate blocks, while in exp. 2, they were presented together and subjects had to detect visual targets at attended locations. Stimuli at attended positions elicited enlarged sensory-evoked potentials and an enhanced negativity at midline electrodes as compared with unattended stimuli. The latter effect was, however, modulated by the location of the preceding stimulus. At frontocentral electrodes, it was larger for stimuli that were preceded by stimuli at the contralateral side as compared with stimuli preceded by stimuli at the same location. It is argued that this effect may be due to a different amount of processing required for the preceding stimulus. When the predecessor is at a to-be-attended location, it has to processed more intensively which may interfere with the processing of the next stimulus.
在一种实验情境中记录了与事件相关电位（ERP），即让受试者在整个实验单元中选择性地关注左侧或右侧，并在关注位置检测偶尔出现的目标刺激。刺激在关注和未关注位置随机呈现。在实验1中，视觉和听觉刺激在不同单元呈现，而在实验2中，它们一起呈现，受试者必须在关注位置检测视觉目标。与未关注刺激相比，关注位置的刺激引发了更大的感觉诱发电位以及中线电极处增强的负电位。然而，后一种效应受到先前刺激位置的调节。在前额中央电极处，与相同位置先前刺激后的刺激相比，对侧位置先前刺激后的刺激引发的效应更大。有人认为，这种效应可能是由于先前刺激所需的处理量不同所致。当前驱刺激处于待关注位置时，它必须更深入地进行处理，这可能会干扰下一个刺激的处理。
