Memory, Attention, and Default Mode Processes in Human Posteromedial Cortex

描述(申请人提供)：人类思维的特点是在处理来自物理环境的信息和处理来自长期记忆的自发产生的信息之间以当前关注、未来计划、愿望和回忆的形式不断相互作用。这项提议旨在探索这种相互作用是如何通过特定的大脑结构实现的。为此，我们建议研究人类后内侧皮质(PMC)的功能，并确定其与外侧顶叶(LPC)和内侧颞叶(MTL)结构的相互作用，这些结构有助于抑制注意力和记忆。PMC是大脑结构的重要组成部分，在执行外部定向注意任务时，它表现出活动减少，而当受试者没有参与任何外部互动和走神时，它在休息状态下表现出更高的活动。到目前为止，人类大脑中PMC功能的神经生理学相关性，包括它的解剖学和时间特异性，仍然没有被探索。我们将通过直接监测和可逆地改变PMC的活动来解决这一知识差距，在被植入颅内电极的清醒人类受试者的注意力和记忆认知任务中，作为常规手术前癫痫评估的一部分。拟议中的工作将是第一个 目的：将直接脑电地形图(ECoG)和脑电刺激(EBS)联合应用于人类PMC。每个PMC亚区的神经生理活动将以高时间分辨率和个体解剖精度直接记录下来，并将被改变以测试注意力和记忆条件下PMC每个亚区的暂时性损害的影响。我们的总体框架是，PMC的两个亚区，即后扣带回皮质(PCC)和脾后皮质(RSC)，分别与注意和记忆网络具有不重叠的作用和选择性的相互作用。由此产生的进展有望揭示与注意缺陷障碍、自闭症、癫痫和痴呆症患者的PMC功能障碍有关的缺陷。

DESCRIPTION (provided by applicant): Human mind is hallmarked by a continuous interplay between processing information from the physical environment and processing spontaneously generated information from long-term memory in the form of current concerns, future plans, wishes and recollections. This proposal aims to explore how this interplay is made possible by specific brain structures. For this purpose, we propose to study the function of the human posteromedial cortex (PMC) and determine its interaction with lateral parietal cortex (LPC) and medial temporal lobe (MTL) structures known to subserve attention and memory. The PMC is an important part of the brain structures that demonstrate reduced activity during the performance of externally directed attention tasks, while demonstrating higher activity during resting states when subjects are not engaged in any external interactions and when their minds wander. To date, the neurophysiological correlates of PMC function in the human brain, including its anatomical and temporal specificity, remain unexplored. We will address this gap of knowledge by directly monitoring and reversibly altering the activity of the PMC during cognitive tasks of attention and memory in conscious human subjects who are implanted with intracranial electrodes, as part of routine presurgical epilepsy evaluation. The proposed work will be the first to combine direct electrocorticography (ECoG) and electrical brain stimulation (EBS) in the human PMC. The neurophysiological activity of each PMC subregion will be directly recorded with high temporal resolution and individual subject anatomical precision, and will be altered to test the effect of 'transient lesions' in each subregion of the PMC during attention and memory conditions. Our overarching framework is that two PMC subregions, namely the posterior cingulated cortex (PCC) and the retrosplenial cortex (RSC), have non-overlapping roles and selective interactions with the networks of attention and memory, respectively. The resulting progress promises to shed light on the deficits associated with PMC dysfunction, in patients with attention deficit disorders, autism, epilepsy, and dementia.