Neural bases of cognitive ERPs:: More than phase reset
Neural bases of cognitive ERPs:: More than phase reset
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DOI：
10.1162/0898929042568514
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发表时间：
2004-11-01
影响因子：
3.2
通讯作者：
Fernández, G
中科院分区：
文献类型：
--
作者：
Fell, J;Dietl, T;Fernández, G
到目前为止，两种相互矛盾的理论试图解释平均事件相关电位（ERP）的起源：而一个假设声称ERP源于与背景动力学不同的事件相关的神经组件的激活，而其他假设则指出ERP的其他假设。是通过持续振荡活性的相位重置产生的。到目前为止，这个问题仅针对早期的ERP组件解决。然而，通常认为晚期的ERP成分代表了几种解剖学上不同大脑区域的叠加活动。因此，哪种机制是基于头皮记录的晚期ERP组件的起源的基础。相比之下，癫痫患者的人体内侧颞叶（MTL）在癫痫患者内部记录的两个精心审查的晚期ERP成分，所谓的MTL-P300和前MTL-N400（AMTL-N400）是基于单一源的。活动。因此，我们研究了MTL-P300和AMTL-N400是基于事件相关的活性增加，持续振荡活性的相位或两者兼而有之。在执行视觉奇数范式和视觉词识别范式的受试者中，从海马和鼻皮层记录了ERP。使用小波技术，分析了与刺激相关的相位锁定和功率变化的频率范围，该频率范围涉及2至48 Hz。我们发现MTL-P300均伴随着相位和功率增加P300，并且两者都会及时重叠。相比之下，AMTL-N400最初与相位锁定无关，而无需增加功率，直到在OUT AMTL-N400的过程中，我们才观察到额外的功率增加。总之，这两个方面，与事件相关的神经组件的激活以及正在进行的活动的相位重置似乎参与了认知任务中记录的后期ERP成分的产生。因此，对事件相关功率和相锁定变化的单独分析可能揭示了对不同认知功能基础机制的特定相关见解。
Up to now, two conflicting theories have tried to explain the genesis of averaged event-related potentials (ERPs): Whereas one hypothesis claims that ERPs originate from an event-related activation of neural assemblies distinct from background dynamics, the other hypothesis states that ERPs are ground produced by phase resetting of ongoing oscillatory activity. So far, this question has only been addressed for early ERP components. Late ERP components, however, are generally thought to represent superimposed activities of several anatomically distinct brain areas. Thus, the question of which mechanism underlies the genesis of late ERP components cannot be easily answered based on scalp recordings. In contrast, two well-investigated late ERP components recorded invasively from within the human medial temporal lobe (MTL) in epilepsy patients, the so-called MTL-P300 and the anterior MTL-N400 (AMTL-N400), are based on single source activity. Hence, we investigated whether the MTL-P300 and the AMTL-N400 are based on an event-related activity increase, a phase reset of ongoing oscillatory activity or both. ERPs were recorded from the hippocampus and rhinal cortex in subjects performing a visual oddball paradigm and a visual word recognition paradigm. With wavelet techniques, stimulus-related phase-locking and power changes were analyzed in a frequency range covering 2 to 48 Hz. We found that the MTL-P300 is accompanied by both phase reset and power increase P300 and that both effects overlap partly in time. In contrast, the AMTL-N400 is initially associated with phase locking without power increase and only later during the course of the out AMTL-N400 we observed an additional power increase. In conclusion, both aspects, event-related activation of neural assemblies and phase resetting of ongoing activity seem to be involved in the generation of late ERP components as recorded in cognitive tasks. Therefore, separate analysis of event-related power and phase-locking changes might reveal specific related insights into the mechanisms underlying different cognitive functions.