Cycowicz Yael M, Friedman David
Cognitive Electrophysiology Laboratory, New York State Psychiatric Institute, 1051 Riverside Drive, Unit 6, New York, NY 10032, USA.
Clin Neurophysiol. 2004 Jun;115(6):1359-67. doi: 10.1016/j.clinph.2004.01.008.
Novel environmental sounds that are task-irrelevant in the novelty oddball paradigm elicit the novelty P3 or P3a with a fronto-central scalp distribution, while pure tone task-relevant stimuli elicit a P3 with a posterior topography (P3b). To determine whether stimulus nature or its function in the task modulates scalp topography, the role of the two types of stimuli during the novelty oddball task was reversed.
Brain electrical activity was recorded while 12 young adults listened to frequent tones, infrequent tones, and infrequent environmental sounds. Subjects were not informed about the infrequent tones, but were instructed to press a reaction time (RT) button when they heard the infrequent environmental sounds.
Despite the "novelty" nature of the tones, they were associated with a posterior scalp distribution typical of the P3b. Similarly, despite the "target" nature of the environmental sounds, they were associated with a fronto-central scalp topography typical of the P3a.
These data suggest that the elicitation of a novelty P3 depends not only on task demands but also on the physical nature of the stimulus.
The brain's orienting response is modulated by the contextual environment as well as the physical properties of the eliciting stimulus.
在新奇奇球范式中与任务无关的新型环境声音会引发头皮额中央分布的新奇P3或P3a，而纯音任务相关刺激会引发具有后部地形的P3（P3b）。为了确定刺激的性质或其在任务中的功能是否调节头皮地形图，在新奇奇球任务期间将两种类型刺激的作用进行了反转。
记录12名年轻成年人在听频繁音调、不频繁音调以及不频繁环境声音时的脑电活动。未告知受试者有关不频繁音调的信息，但指示他们在听到不频繁环境声音时按下反应时间（RT）按钮。
尽管音调具有“新奇”性质，但它们与典型P3b的后部头皮分布相关。同样，尽管环境声音具有“目标”性质，但它们与典型P3a的额中央头皮地形图相关。
这些数据表明，新奇P3的诱发不仅取决于任务要求，还取决于刺激的物理性质。
大脑的定向反应受上下文环境以及诱发刺激的物理特性调节。
