Structural and functional architecture of the prefrontal cortex for working memory
Speaker: Jacob Miller
The prefrontal cortex (PFC) is consistently active during working memory (WM) tasks, but there is debate regarding its specific role in support of WM behavior across studies, scales, and species. In this talk, I will detail how a precision neuroimaging approach can help bridge discrepant findings regarding the nature of PFC function. First, I will showcase how a unique, longitudinal sampling of WM representations across long-term learning uncovers PFC activity patterns more typically found in non-human primate electrophysiology studies vs. human neuroimaging. To do this, three human participants each completed over 20 sessions of functional MRI (fMRI) along with at-home training over three months. During this time, participants repeatedly performed a delayed recognition WM task and a sequence learning task with complex fractal stimuli. Across the course of training, both stimulus-specific and categorical WM representations emerged across different PFC areas. Second, I will detail how anatomical and functional properties of human PFC facilitate (and constrain) WM and other flexible behavior. Careful identification of individual-level anatomical features in PFC reveals relationships between neuroanatomy and cognition, and helps us map the “cognitive globe” of the PFC. Finally, I will dive below the level of voxels into microscale organization and show how WM operates at different spatial scales in PFC circuits. This framework bridges the neural architecture for WM across scales of centimeters (cortical folding), millimeters (voxels), and microns (single-cells). Collectively, the tools and lessons of individual-level functioning and neuroanatomy allow us to characterize robust brain-behavior relationships that advance our understanding of WM and related cognitive processes in the PFC.