Episodic Memory Encoding: fMRI Investigations

描述（由申请人提供）：拟议研究的首要目标是从认知神经科学的角度来理解关于事件的信息是如何成功地编码到情景记忆中的。功能性磁共振成像（fMRI）将用于识别在成功编码实验项目（如文字和图片）及其与其他项目（项目-项目编码）或与一个或多个上下文特征（项目-上下文编码）的关联过程中引发的神经活动。指导本研究的理论视角来自以下建议：情景记忆是根据经历的事件所参与的加工来表示的，成功的情景编码要求构成事件的各种特征被“绑定”或整合到一个内聚记忆表征中。在这一观点的指导下，实验将探讨大脑皮层和内侧颞叶在“绑定”内模态与跨模态项目-背景和项目-项目关联中的作用。其他实验将研究不同情境特征之间的内模态和跨模态关联形成的神经关联。另一个实验将研究在不同时间呈现的项目之间形成时间关联的神经关联。在研究的第二部分中，重点将放在神经活动上，这些神经活动似乎在情景编码中起着“允许”的作用，而不是支持特定学习任务所涉及的过程。将进行实验来阐明i)在一些皮层区域，通过学习项目引起的神经活动相对衰减的功能意义，这些研究项目在以后的记忆测试中被记住而不是被遗忘，ii)预刺激活动的调节也可以预测以后的记忆表现。情景记忆的致残性损伤在几种常见的神经系统疾病中很突出，特别是阿尔茨海默病和创伤性脑损伤。情景记忆功能障碍也是一些常见精神疾病的重要组成部分，包括精神分裂症、抑郁症和创伤后应激障碍。此外，相对于其他类型的记忆，情景记忆随着年龄的增长而显著下降。该研究将有助于详细了解支持正常情景记忆功能的神经认知过程，这对于阐明不同类型的情景记忆障碍和开发有效的治疗干预措施是必要的。

DESCRIPTION (provided by applicant): The overarching goal of the proposed research is to understand, from a cognitive neuroscience perspective, how information about an event is successfully encoded into episodic memory. Functional magnetic resonance imaging (fMRI) will be employed to identify neural activity elicited during the successful encoding of experimental items such as words and pictures and their associations either with other items (item-item encoding), or with one or more contextual features (item-context encoding). The theoretical perspective guiding the proposed research derives from the proposals that an episodic memory is represented in terms of the processing engaged by an event as it is experienced, and that successful episodic encoding requires that the various features constituting an event are 'bound' or integrated into a cohesive memory representation. Guided by this perspective, experiments will address the roles of the cerebral cortex and the medial temporal lobe in the 'binding' of within- versus across- modality item-context and item-item associations. Other experiments will investigate the neural correlates of the formation of within- and across-modality associations between different contextual features. Another experiment will investigate the neural correlates of the formation of temporal associations between items presented at different times. In a second strand of the research, the focus will be on neural activity that appears to play a 'permissive' role in episodic encoding, rather than supporting processes engaged by a specific study task. Experiments will be conducted to elucidate i) the functional significance of the relative attenuation of neural activity elicited in some cortical regions by study items that are remembered rather than forgotten on a later memory test, and ii) modulations of pre-stimulus activity that also are predictive of later memory performance. Disabling impairments of episodic memory are prominent in several common neurological conditions, notably Alzheimer's disease and traumatic brain injury. Episodic memory dysfunction is also a significant component of several common psychiatric disorders, including schizophrenia, depression and post-traumatic stress disorder. In addition, episodic memory declines substantially and, relative to other kinds of memory, disproportionately, with increasing age. The proposed research will contribute to the detailed understanding of the neurocognitive processes that support normally-functioning episodic memory, an understanding that is necessary for the elucidation of different kinds of episodic memory disorders and the development of effective therapeutic interventions.