Guo Wanjia
The events and related details that can be stored human memories is almost unlimited. However, sometimes we still confuse one experience with another: which sweater is the one I received as a Christmas gift in 2018, and which one is from 2016?
My ongoing predoctoral research with Dr. Brice Kuhl focuses on identifying hippocampal mechanisms that support the disambiguation of similar episodic memories. In the most recent project, we found that the moment when participants were able to resolve memory interference (associating a correct object with the correct scene, instead of its very similar competitor), the CA3/dentate gyrus (a subfield in the hippocampus) showed abrupt decorrelation between the scene and its highly similar competitor. In other words, there is a temporal coupling between hippocampus decorrelation and behavioral expression of successful learning.
This project leads to more intriguing questions about how the hippocampus supports the distinguishing among similar memories that I am hoping to answer with future projects. For example, what are the causes and consequences of decorrelated hippocampus representations? Can we locate and predict the precise timing of changes in hippocampus representations? Can we predict the degree of decorrelation in the hippocampus?
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During the 2 years in Dr.
Anthony Wagner’s
lab at Stanford University, I contributed to a large, multimodal neuroimaging project studying healthy aging in collaboration with Dr.
Beth Mormino
from the Stanford Neurology Department. The project incorporated measures of Tau/PET, CSF, and structural and functional f/MRI in the hippocampus to understand the individual differences in age-related memory decline. Working with Dr. Beth Mormino, I implemented an analysis pipeline and analyzed Tau/PET imaging data for healthy aging adults, MCI and dementia patients. Working under the supervision of Dr. Scott Guerin and Dr. Alexandra Trelle, I manually segmented and analyzed over 100 structural MRI images from healthy older adults to identify sub-regions of the hippocampus and medial temporal lobe, implemented an automated a program to analyze free response behavioral data, and contributed to study design during the project’s transition to a longitudinal extension.
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Also during my 2-year research assistantship in
Stanford Memory Lab, I worked closely with Dr.
Jiefeng Jiang
to investigate the relationship between cognitive control and long-term episodic memory. I collected and analyzed behavioral data using reinforcement learning models. We found that memory-guided cognitive control and adaptive behavior are supported by hippocampal-prefrontal interactions.
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At the University of Wisconsin-Madison, I spent one and a half years as an undergraduate research assistant in the laboratory of Dr. Brad Postle studying visual working memory. It was the first time that I had a chance to collect and analyze behavioral, EEG, and EEG/TMS data with human participants. Enjoying my experience at the Postlab and working with human participants, I conducted a senior thesis research investigating how visual working memory, which has a limited storage space, allocates incoming information under the guidance of Dr. Andrew Sheldon. Participants were shown moving dots with two dimensional features (directions and colors), where the memory load of each feature was manipulated independently. I found that the recall precision of a certain feature decreased as there were increases in the memory loads of that feature. Conversely, the precision of one feature was not influenced by increasing the memory load of the other feature.
© 2020-2022 Wanjia Guo.