NEURAL AND COGNITIVE BASIS OF THE P300 AND N400

事件相关电位(ERPs)提供毫秒的时间分辨率 认知过程背后的神经活动。研究利用 植入电极的行为人体、动物模型、神经模型 颅脑来源与神经科局灶性脑病的研究 新皮质或边缘区域的损害提供了汇聚 关于事件相关电位的颅内发生器的信息。因此，ERPS 构成一种测量认知活动的生理学方法 具有高的时间和空间分辨率。局灶性脑出血患者的临床研究 脑损伤表明，P300反应，最初提出是 一种么正现象，具有多个通道独立生成器 前额叶皮质、颞顶交界区和海马区 队形。结合行为学和医学学的患者研究 电生理技术可以提供关于 不同ERP成分对特定ERP波幅的认知基础 减少可以与定义的行为缺陷联系在一起。世界经济的理论 P300的认知基础以注意和记忆为中心 尽管目前还没有达成共识。N400响应已链接到 语言处理和获取长期记忆存储。较少 关于神经源的信息是可用的，尽管是在颅内 记录报道了内嗅皮层中的N400样活性。近期 本实验室收集的神经科局灶性脑病患者的资料 脑损伤的区域表明P300和N400的反应可能是 早期在新皮质和边缘区域产生的神经活动 注意力和工作记忆过程。在目前的提案中，我们将 接受MRI检查的患者组确定了以下两个区域的损害 前额叶或后叶联合皮质或内侧颞区 包括海马体和邻近的内嗅皮层。结合了ERP和 将使用行为方法来检验P300的认知理论 和N400代。这种方法还可以进一步洞察 负责产生P300和N400的神经区。

Event-related potentials (ERPs) provide millisecond temporal resolution of neural activity underlying cognitive processing. Research utilizing implanted electrodes in behaving humans, animal models, neural modeling of intracranial sources and study of neurological patients with focal damage in neocortical or limbic regions has provided converging information on the intracranial generators of ERPs. Thus, ERPs constitute a physiological method for measurement of cognitive activity with high temporal and spatial resolution. Study of patients with focal brain damage has shown that the P300 response, initially proposed to be a unitary phenomenon, has multiple modality independent generators in cortex in prefrontal regions, temporal-parietal junction and hippocampal formation. Patient research utilizing combined behavioral and electrophysiological techniques may provide additional information on the cognitive basis of different ERP components since specific ERP amplitude reductions can be lined to defined behavioral deficits. Theories of the cognitive basis of P300 have centered around attention and memory although no consensus has emerged. The N400 response has been linked to linguistic processing and access to the long-term memory store. Less information on neural sources is available although intracranial recording has reported N400-like activity in entorhinal cortex. Recent data collected in our laboratory in neurological patients with focal areas of brain damage suggest that the P300 and N400 responses may index neural activity generated in neocortical and limbic regions during early attention and working memory processes. In the current proposal we will study groups of patients with MRI defined damage in subregions of either prefrontal or posterior association cortex or in mesial temporal areas including hippocampus and adjacent entorhinal cortex. Combined ERP and behavioral methods will be employed to test cognitive theories of P300 and N400 generation. This approach may also provide further insight into the neural regions responsible for generation of the P300 and N400.