Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

The proposed research aims to understand the role of thalamic subregions in memory processing. While previous research has focused on a single subcortical structure called the hippocampus and nearby medial temporal lobe (MTL) cortices, this narrow focus may have resulted in the failure to detect critical contributions of other brain regions to memory processes. The proposed research will expand this focus by investigating the role of the extended hippocampal system (including subcortical grey and white matter structures that serve as its direct inputs and outputs) to form a more comprehensive understanding of how the brain supports memory. Specifically, while preliminary evidence suggests that some regions of the thalamus may play a key role in memory function, these regions have been largely overlooked by neuroimaging studies to date. This research will probe the functional and structural connectivity of the thalamus to the MTL and prefrontal cortices (PFC), as well as characterize the functional contributions of the thalamic subregions to memory processing.

The thalamus's role in memory is an exciting new area of study in the field of memory research. Damage to the thalamus causes memory difficulties or even amnesia, resulting in similar memory impairments as when the MTL is damaged. Specific thalamic subregions are interconnected with the MTL, as well as neocortical regions, such as the PFC, which are involved in higher-level cognition such as memory, attention, and decision-making. This pattern of connectivity is especially intriguing for the field of memory research, because currently little is known about how the PFC exerts top-down control to modulate memory formation and goal-directed memory retrieval. Neural oscillations, which are created by synchronized neuronal firing, are thought to underlie the mechanisms by which the thalamus coordinates these MTL-PFC interactions. This research will address how the thalamus interacts with the MTL and the PFC in support of the formation of memory associations, the retrieval of associated information, and the processing of different types of memories.

This research will use a comprehensive cognitive neuroscience approach— including high-resolution structural MRI and magnetoencephalography—to better characterize subcortical and neocortical networks involved in memory function, with a specific focus on the contributions of thalamic subregions to memory. This research program will provide unique opportunities for trainees to gain cutting-edge experience using comprehensive neuroimaging techniques to advance our understanding of human memory. I anticipate that the proposed research will reveal the previously ignored but pivotal role of the thalamic subregions in memory and that this research will provide a meaningful remapping of our understanding of the neuroanatomical basis of memory function.