NEURAL AND COGNITIVE BASIS OF THE P300 AND N400

事件相关电位（ERP）提供毫秒级的时间分辨率 认知过程中的神经活动 研究利用 在行为人类、动物模型、神经模型中植入电极 颅内源的研究和神经系统患者的局灶性 新皮层或边缘区的损伤 关于颅内ERP发生器的信息。 因此，ERP 构成了一种测量认知活动的生理学方法 具有很高的时间和空间分辨率。 局灶性脑梗死患者的研究 脑损伤表明，P300反应，最初被认为是 一个单一的现象，有多个模态独立的发电机， 前额叶皮层、颞顶交界区和海马 阵 患者研究采用结合行为和 电生理学技术可以提供关于 不同ERP成分的认知基础，因为特定的ERP幅度 减少可以与定义的行为缺陷相一致。 发展中心 P300的认知基础主要围绕注意和记忆 尽管没有达成共识。 N400的反应与 语言处理和进入长期记忆库。 少 虽然颅内神经源的信息是可用的， 记录已经报道了内嗅皮层中的N400样活性。 最近 在我们的实验室中收集的局灶性神经系统患者的数据 脑损伤的区域表明，P300和N400反应可能指示 早期大脑皮层和边缘区产生的神经活动 注意力和工作记忆过程。 在目前的提案中，我们将 研究组中，MRI定义的损伤发生在 前额叶或后联合皮层或颞叶内侧区 包括海马体和邻近的内嗅皮质。 合并的ERP和 行为学方法将被用来检验P300的认知理论 N400代 这种方法还可以进一步深入了解 负责产生P300和N400的神经区域。

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.