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理解关于事件的信息如何成功地编码到情景记忆中。功能磁共振成像(FMRI)将被用来识别在成功编码实验项目(如单词和图片)期间引发的神经活动，以及它们与其他项目(项目-项目编码)或一个或多个上下文特征(项目-上下文编码)的关联。指导这项研究的理论观点源于这样的观点，即情景记忆是根据事件在经历时所进行的加工来表示的，并且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连贯的记忆表征中。在这一观点的指导下，实验将解决大脑皮层和内侧颞叶在通道内与跨通道项目-上下文和项目-项目关联的“绑定”中的作用。其他实验将研究不同语境特征之间形成内通道和跨通道关联的神经关联。另一项实验将调查在不同时间呈现的物品之间形成时间关联的神经关联。在这项研究的第二条线索中，重点将放在神经活动上，这些神经活动似乎在情景编码中扮演着“允许”的角色，而不是支持由特定研究任务参与的过程。实验将被用来阐明i)在以后的记忆测试中被记住而不是被遗忘的学习项目在某些皮质区域引起的神经活动相对减弱的功能意义，以及ii)刺激前活动的调制也可以预测以后的记忆表现。情节记忆的残疾在几种常见的神经疾病中都很突出，特别是阿尔茨海默病和创伤性脑损伤。间歇性记忆障碍也是几种常见精神障碍的重要组成部分，包括精神分裂症、抑郁症和创伤后应激障碍。此外，随着年龄的增长，情节记忆显著下降，而且与其他类型的记忆相比，下降得不成比例。这项拟议的研究将有助于详细了解支持正常功能情景记忆的神经认知过程，这一理解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。公共卫生相关性：在许多神经学和精神病学疾病中都会发现情景记忆--对独特事件的记忆--的失能障碍。这项拟议的研究将有助于详细了解正常功能的情景记忆，这对于充分理解和有效治疗不同类型的情景记忆障碍是必要的。

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. PUBLIC HEALTH RELEVANCE: Disabling impairments of episodic memory - memory for unique events - are found in numerous neurological and psychiatric conditions. The proposed research will contribute to the detailed understanding of normally-functioning episodic memory that is necessary if different kinds of episodic memory disorders are to be fully understood and effectively treated.