Rachel A. Diana, PhD - US grants

[unreadable] DESCRIPTION (provided by applicant): The ability to remember past events, or episodic memory, is critical to our daily activities. A central feature of episodic memories is that they are associated with a specific context-a time, place, and situation. Indeed, most research in psychology and neuroscience has conceptualized episodic recollection as the retrieval of an association between an item and the context in which the item was encountered. According to a recently proposed model, three regions in the medial temporal lobes (MIL)-the perirhinal cortex (PRc), parahippocampal cortex (PHc), and hippocampus-make qualitatively different contributions to the encoding of item information, context information, and the binding of item information to episodic context, respectively. The specific aims of this proposal are to test two predictions stemming from this model: 1) To test the hypothesis that encoding of context information is dissociable from encoding of item-context associations, both in terms of cognitive performance and electrophysiological activity, and that this context information differentially supports memory retrieval using recognition and recall. 2) To test the hypothesis that the perirhinal cortex (PRc), parahippocampal cortex (PHc), and hippocampus are differentially involved in encoding of item representations, context representations, and representations of item-context bindings Exp. 1 will manipulate contextual uniqueness to determine whether context information can be strengthened independently from item-context associations during encoding. This additional contextual strength should be evident in the ERP subsequent memory effects and is expected to support recall performance but not recollection performance. Exp. 2 will use fMRI scanning during encoding to compare storage of repeated items, repeated contexts, and repeated item-context bindings, allowing dissociation of the areas involved in storage of item information and contextual information. Exp. 3 will also use fMRI scanning during encoding to further investigate the role of parahippocampal cortex in storage of context information, testing encoding of spatial vs. verbal context and task-determined designation of context. Relevance: Impairments in episodic memory in psychiatric (e.g., schizophrenia and depression) and neurological (e.g., Alzheimer's Disease) disorders have a debilitating effect on patients' quality of life. By specifying the neural underpinnings of episodic memory processes, this research can inspire new diagnostic and therapeutic approaches these conditions. [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): A central feature of episodic memories is that each item to be remembered is associated with a specific context-a time, place, and situation. According to the BIC model of MTL function (Diana, Ranganath, &Yonelinas, 2007), three regions in the medial temporal lobes (MTL)-the perirhinal cortex (PRc), parahippocampal cortex (PHc), and the hippocampus-make qualitatively different contributions to the encoding of item information, context information, and the binding of items to episodic context, respectively. Alternative MTL models exist, however the BIC model is unique in its focus on differentiating the roles of the PRc and PHc. PHc function is the least well understood of the MTL subregions. The BIC model makes predictions both for the role of PHc in memory and the cognitive relationships between item and context information that can affect memory. This application will test the BIC model's predictions about the cognitive and neural bases of episodic memory. Specific Aims: 1)To examine the dynamics of episodic information, testing the cognitive hypothesis that item and context information are typically represented as separate pieces of information but can be unitized under specific encoding conditions. We will use ERP and behavioral methods to explore these cognitive questions regarding item and context information in memory. 2) To test the neural hypothesis that PHc and PRc activations are dissociable and are differentially involved in encoding of context representations and item representations, respectively. We will use fMRI methodology to dissociate the functions of PHc and PRc in memory. 3) To identify the nature of context information represented in the PHc, testing the neural hypothesis that PHc encodes spatial, semantic, and temporal context information. We will use fMRI methodology to define the nature of memory representations in PHc. The proposed projects will provide training in ERP, fMRI, and patient methodologies, enabling me to pursue my goal of becoming an independent investigator of the cognitive neuroscience of human memory. I intend to complete my training through two additional years of postdoctoral research and then obtain a position at a major research university to continue my research.

PROJECT SUMMARY / ABSTRACT Our investigation is a developmental cognitive neuroscience examination of inhibitory control during infancy. Using a cross-sectional research design, we will test whether neurophysiological levels of analysis distinguish between two specific types of inhibitory control during infancy: attention inhibition and cognitive inhibition. Infants will be seen either at 9 or at 12 months of age and will complete two inhibitory control tasks while brain electrophysiology is recorded. We will use ERP components associated with inhibitory control, attention, and memory to characterize the two types of inhibitory control processes. Importantly, we will identify ERP components associated with inhibitory control during infancy, currently a major gap in the developmental research literature and an innovation of our study. Our proposed study is critical for understanding early cognitive development and we do so by contributing to the basic cognitive neuroscience work on inhibitory control. We will address three research aims. 1) We will compare attentional and memory ERP components on two types of inhibitory control tasks at 9 and 12 months of age. 2) We will determine and identify infant- specific ERP components related to the inhibitory control. 3) We will examine age-related differences in attention, memory, and inhibitory control ERP components.