Elizabeth F. Chua - US grants

DESCRIPTION (provided by applicant): The objectives of this SCORE 2 (SC2) grant are to identify cognitive and neural factors that drive subjective confidence in memory, and determine which of these are more tightly related to memory accuracy. Determining what kinds of confidence judgments are more accurate, and encouraging use of those kinds of judgments, may eventually lead to better memory awareness and compensation for any experienced decline in memory function and metamemory (i.e., knowledge of one's own memory) in specific neurologic and psychiatric disorders. The cognitive neuroscience of metamemory has been understudied given the consequences for public health. Neuroimaging studies have shown that the medial temporal lobes (MTL) and prefrontal cortices (PFC) contribute to memory and memory confidence. However, there is debate about how and when they contribute to confidence. Candidate mechanisms by which the MTL and PFC contribute to confidence include binding, subjective remembering, inferential reasoning, and monitoring. The experiments in this proposal aim to determine when MTL and PFC activity gives rise to subjective confidence, and to identify which sources of information form the basis for accurate confidence judgments (i.e., when confidence and accuracy are concordant). The proposed experiments provide a novel way to measure and track confidence judgments based on different sources of information, using eye tracking and fMRI. Eye movements can provide a sensitive measure of memory without requiring overt responses and are used in this proposal as an index of underlying cognitive mechanisms. With this increased specificity of the underlying cognitive mechanisms, combining eye tracking with fMRI will lead to a better specification of the neural mechanisms underlying memory confidence, and consequently a better understanding of the roles and functions of the MTL and PFC. Brooklyn College of the City University of New York provides an excellent environment for involving individuals from under-represented groups at all levels from faculty and graduate students to undergraduate and even high school students. Dr. Chua will be mentored by Dr. Lila Davachi, an Associate Professor at New York University, who has a productive and well-funded laboratory that has made significant contributions to determining the role of various medial temporal lobe structures in memory. With Dr. Davachi's mentorship, Dr. Chua will be well positioned to begin a strong, independent research career, enabling her to involve more students from under-represented minorities in quality research.

The objectives of this SC3 grant are to determine the neural mechanisms that support memory awareness (i.e., knowing when you remember and when you do not) and metacognitive control of memory (e.g., being able to use appropriate strategies to improve memory), and whether they can be enhanced via non-invasive brain stimulation. This research lays the groundwork for the development of brain stimulation- based interventions that would improve impairments in memory awareness and memory functions for individuals with neurological and psychiatric disorders. Specifically, the experiments in this proposal examine accurate memory awareness by using `metamemory' tasks, in which participants report their confidence about their future memory performance. Confidence about future memory performance is compared with actual memory performance, which provides an objective measure of memory awareness. I have previously shown that high definition transcranial direct current stimulation (HD-tDCS), a type of brain stimulation, over the dorsolateral prefrontal cortex (DLPFC) leads to improved memory awareness, and that this result replicates. The proposed experiments are logical extensions of this exciting finding. First, Exps. 1-2 apply different kinds of brain stimulation that differ in strength, spatial focality, and potential side effects, in order to test what form of brain stimulation is optimal for pursuing as a potential intervention. Next, Exps. 3-4 test whether there are also brain stimulation-induced improvements in memory awareness using different kinds of memory tasks. This will inform which kinds of tasks are most likely to show brain stimulation-based improvements in memory awareness. Finally, Exps. 5-6, test whether brain stimulation-based improvements in memory awareness lead to improvements in memory performance via metacognitive control mechanisms. In other words, if memory awareness is improved, does this knowledge about one's memory also lead to better strategic decision making to improve memory. From a basic research perspective, the proposed experiments will lead to gains in scientific knowledge about the neural underpinnings of accurate memory awareness and inform broader theories of prefrontal function. From a health perspective, the proposed experiments have the potential to provide a foundation for brain stimulation- based interventions for impairments in memory awareness. Brooklyn College of the City University of New York provides an excellent environment for involving individuals from under-represented groups at all levels, from faculty and graduate students to undergraduate and even high school students. With continued SCORE support, Dr. Chua will be well positioned to have a strong, independent research career, enabling her to involve more students from under-represented minorities in high quality neuroscience research.