Bridging The Dual Facets of Working Memory: Causal Mapping of Active and Hidden States Using Brain Stimulation and Precision Imaging

In human cognition, working memory (WM) plays a pivotal role, allowing us to “actively” focus on limited information while also maintaining a broader "hidden" cognitive background. Active WM is well-studied and is a common target for mental health interventions. Despite its role in computational models, hidden WM remains elusive because it is not visible using traditional imaging methods. Building upon my imaging work precisely delineating active WM circuits, and recent advances in methods for making hidden circuits visible, I aim to develop a framework that captures both the active and hidden sides of WM. First, I will combine transcranial magnetic stimulation (TMS) concurrently with precision functional MRI (fMRI) to visualize hidden WM circuits. Second, I will integrate human intracranial electrode recordings and stimulation with precision fMRI to causally map the fast dynamics of WM states. Third, I will elucidate the intricate anatomical wirings of WM circuits, which are difficult to decipher in humans, by leveraging a novel tract-tracing dataset in non-human primates. These complementary approaches promise, for the first time, to reconcile active and hidden sides of a vital everyday cognitive process. Further, the unique combination of TMS, intracranial electrodes, and precision fMRI has important implications for circuit-based clinical interventions.