Perirhinal Cortex and Associative Memory

描述（由申请人提供）：成功形成任意联想记忆的能力对大多数日常生活行为至关重要。大量研究表明，海马体在联想记忆中起着至关重要的作用。最近的研究表明，嗅周皮层（PRc）也参与其中，但其在联想记忆中的功能作用知之甚少。这项研究计划将使用功能性磁共振成像（FMRI）和新的行为范式来测试PRc如何有助于联想识别的三种理论： (1)单位化理论认为，如果成对的项目被编码为一个单一的单位，PRc可以支持基于熟悉度的新的关联识别，但海马需要回忆被编码为单独单位的项目之间的关系。新的功能磁共振成像实验，提出了测试是否PRc具体有助于识别的项目，被编码为一个单一的单位之间的关联。平行的行为研究将测试单位化是否影响熟悉度指数。 (2)域理论认为，PRc支持熟悉的识别来自同一处理域的项目之间的关联，但海马需要支持回忆来自不同处理域的项目之间的关联。新的功能磁共振成像研究提出，以测试是否PRc支持来自相同的处理域的项目之间的关联，但不从不同的域的项目之间的关联。此外，行为研究将测试是否域内，而不是跨域的协会影响熟悉的行为指数。 (3)项目和上下文绑定（BIC）理论认为PRc代表项目信息，PHc代表上下文信息，并且这些信息由海马体绑定。功能磁共振成像实验的建议，以测试是否项目信息的回忆将与PRc活动，而上下文信息的回忆将导致PHc活动。 通过对这三种理论的检验，本研究为建立一个综合编码加工、刺激域和提取加工的MTL功能理论奠定了基础。一些精神病患者（例如，精神分裂症）和神经学（例如，阿尔茨海默氏病和创伤性脑损伤）障碍与记忆障碍和内侧颞叶功能障碍有关。拟议的研究可能会导致改善这些疾病的诊断和治疗方法。对内侧颞叶区域记忆功能的基础研究至关重要，因为一些精神病（例如，精神分裂症）和神经系统疾病（例如，阿尔茨海默病和创伤性脑损伤）病症与记忆障碍和MTL功能障碍相关。这种记忆障碍会对患者的生活质量产生破坏性影响。研究澄清记忆的基本神经机制可以改善这些疾病的诊断和治疗。

DESCRIPTION (provided by applicant): The ability to successfully form memories for arbitrary associations is essential for most acts of daily living. Numerous studies have shown that the hippocampus plays a critical role in associative memory. Recent work indicates that the perirhinal cortex (PRc) is also involved, but its functional role in associative memory is poorly understood. This research program will use functional magnetic resonance imaging (FMRI) and novel behavioral paradigms to test three theories of how the PRc contributes to associative recognition: (1) Unitization theory asserts that the PRc can support familiarity-based recognition of novel associations if the paired items are encoded as a single unit, but that the hippocampus is required for recollection of relations between items that are encoded as separate units. Novel FMRI experiments are proposed to test whether the PRc specifically contributes to recognition of associations between pairs of items that were encoded as a single unit. Parallel behavioral studies will test whether unitization influences indices of familiarity. (2) Domain theory asserts that the PRc supports familiarity-based recognition for associations between items from the same processing domain, but that the hippocampus is required to support recollection for associations between items from different processing domains. Novel FMRI studies are proposed to test whether the PRc supports associations between items from the same processing domains, but not associations between items from different domains. In addition, behavioral studies will test whether within-domain, but not across-domain associations influence the behavioral indices of familiarity. (3) Binding of items and contexts (BIC) theory asserts that the PRc represents item information, the PHc represents context information, and that this information is bound by the hippocampus. FMRI experiments are proposed to test whether recall of item information will be associated with PRc activity, whereas the recall of contextual information will lead to PHc activity. By testing the three theories, this proposal can provide the foundation for the development of a comprehensive theory of MTL function that can incorporate the influences of encoding processing, stimulus domain, and retrieval processing. Several psychiatric (e.g., schizophrenia) and neurological (e.g., Alzheimer's disease and traumatic brain injury) disorders are associated with memory impairments and with medial temporal lobe dysfunction. The proposed research may lead to improved diagnostic and therapeutic approaches to these disorders. PUBLIC HEALTH RELEVANCE Basic research on the mnemonic functions of the medial temporal lobe region is critically important because several psychiatric (e.g., schizophrenia) and neurological (e.g., Alzheimer's disease and traumatic brain injury) disorders are associated with memory impairments and MTL dysfunction. Such memory disorders can have a devastating effect on patients' quality of life. Research clarifying the basic neural mechanisms of memory can lead to improved diagnosis and treatment of these disorders.