Poster B67, Sunday, March 25, 8:00-10:00 am, Exhibit Hall C
Ultra-high resolution functional magnetic resonance imaging of hippocampal subfield networks during pattern separation
Stephanie Langella1, Shaina Garrison1, Wei-Tang Chang1, Weili Lin1, Kelly Giovanello1; 1University of North Carolina at Chapel Hill
The dynamic interaction between the hippocampus and neocortical regions is known to be critical for memory functions. The hippocampal formation consists of several distinct subfields, including CA1, CA3, subiculum, and dentate gyrus (DG), each contributing in unique ways to different aspects of memory. Prior ultra-high resolution (e.g., voxel size = 1mm3) functional magnetic resonance imaging (fMRI) studies have been limited to the hippocampus due to technical constraints associated with whole-brain investigations. In the current project, we examined hippocampal subfield-neocortical functional connectivity using a novel ultrahigh-resolution imaging sequence at 7T. Participants completed a continuous recognition version of the Mnemonic Similarity Task while task-based fMRI data were acquired. Preliminary results show increased DG activity, as compared to other hippocampal subfields, when viewing lure stimuli relative to repeated stimuli. Functional connectivity analyses of the task-based data suggest that the visual association cortex has stronger connections with DG, rather than with CA1. These results highlight the utility of using whole-brain ultra-high resolution fMRI to detect differences in hippocampal subfield connectivity beyond the medial temporal lobe. Such investigations may provide critical insight into hippocampal subfield network differences that occur as a function of age and neurodegenerative disease.
Topic Area: LONG-TERM MEMORY: Episodic