Aging Changes to Perceptual and Conceptual Encoding in Perirhinal Cortex

描述（由申请人提供）：嗅周皮层（PRC），内侧颞叶亚区（MTL），是陈述性记忆过程（如熟悉性识别）所必需的。相比之下，海马体（HC）对基于回忆的识别至关重要.相当多的工作调查的结构和功能的完整性，这些MTL亚区在健康老龄化表明，中国和熟悉的是不遗余力的相对HC和回忆。相反，年龄相关的神经认知障碍，如阿尔茨海默病与广泛的MTL病理和记忆障碍有关。这种分离可作为病理老化和痴呆早期诊断的潜在生物标志物。然而，最近的工作挑战这种分离，因为有证据表明，与年龄相关的PRC功能障碍的知觉歧视和证据表明，年龄相关的递减，在PRC量与熟悉障碍。这些数据提高了在某些条件下老年人PRC功能受损的可能性。这是至关重要的，以了解这些条件的界限，因为这对痴呆症的早期诊断和认知训练和康复的影响。 基于其解剖结构和连通性，PRC被提出可分为外侧和内侧部分，分别支持感知和概念处理。与此相一致，有证据表明，从两条线的工作，PRC支持知觉和概念的表征，可以使随后的熟悉，虽然这些不同的文献没有系统地比较。鉴于老年人的概念处理相关的感知受损的证据，可能是感知编码受损导致健康老龄化中的PRC功能障碍和记忆障碍的情况。这两个拟议的fMRI研究探讨是否外侧和内侧PRC分别支持知觉和概念处理，以及是否前者，而不是后者在健康老龄化的影响。研究1考察了与年龄有关的概念变化（例如，词）和感知（例如，与随后的熟悉度有关的面部）歧视，以及这些过程在多大程度上受到外侧和内侧PRC的支持。研究2探讨了与年龄相关的变化，在不同的功能和结构连接网络与横向和内侧PRC支持随后的概念和感知熟悉的编码对象（其中包含概念和感知的细节）。为了评估外侧和内侧PRC对感知和概念信息的敏感性，我们建议检查单变量活动、多体素模式分析（MVPA）和功能连接预测随后熟悉程度的程度。此外，我们将评估行为与外侧和内侧PRC功能和体积之间关系的个体差异，以及白色物质（扩散张量成像）与支持感知和概念过程的其他皮质区域的完整性。这些分析使我们能够更好地了解如何以及在何种程度上健康老龄化影响的概念和感知表征认为，在中国的熟悉度。

DESCRIPTION (provided by applicant): The perirhinal cortex (PRC), a medial temporal lobe subregion (MTL), is necessary for declarative memory processes such as familiarity-based recognition. In contrast, the hippocampus (HC) is critical for recollection- based recognition. Considerable work investigating the structural and functional integrity of these MTL subregions in healthy aging indicates that PRC and familiarity are spared relative to HC and recollection. In contrast, age-related neurocognitive disorders such as Alzheimer's disease are associated with broad MTL pathology and memory impairments. This dissociation serves as a potential biomarker of pathological aging and early diagnosis of dementias. However, recent work challenges this dissociation, as there is evidence of age-related PRC dysfunction in perceptual discriminations and evidence that age-related decrements in PRC volume are related to familiarity impairments. These data raise the possibility of impaired PRC function in older adults under certain conditions. It is critical to understand the boundaries of such conditions given the implications for both early diagnosis of dementias and cognitive training and rehabilitation. Based on its anatomy and connectivity, PRC has been proposed to be divisible into lateral and medial portions that respectively support perceptual and conceptual processing. Consistent with this, there is evidence from two lines of work that PRC supports both perceptual and conceptual representations that can subserve subsequent familiarity, although these disparate literatures have not systematically compared. Given evidence of impaired perceptual relative to conceptual processing in older adults, it may be the case that impaired perceptual encoding accounts for PRC dysfunction and memory impairments in healthy aging. The two proposed fMRI studies explore whether lateral and medial PRC respectively supports perceptual and conceptual processing, and whether the former but not the latter is affected in healthy aging. Study 1 examines age-related changes in conceptual (e.g., word) and perceptual (e.g., face) discriminations that relate to subsequent familiarity, and the extent to which these processes are supported by lateral and medial PRC. Study 2 explores age-related changes in differential functional and structural connectivity networks with lateral and medial PRC supporting the subsequent conceptual and perceptual familiarity of encoded objects (which contain both conceptual and perceptual details). To assess the sensitivity of lateral and medial PRC to perceptual and conceptual information, we propose to examine the extent to which univariate activity, multi- voxel pattern analysis (MVPA), and functional connectivity predicts subsequent familiarity. Moreover, we will assess individual differences in the relationship between behavior and lateral and medial PRC function and volume, as well as white matter (diffusion tensor imaging) integrity with other cortical regions supporting perceptual and conceptual processes. These analyses allow us to better understand how and to what extent healthy aging affects conceptual and perceptual representations thought to subserve familiarity in PRC.