Closing the Loop on Working Memory

Working memory — the capacity to hold and manipulate information in mind over seconds — is central to almost every demanding cognitive task, and its disruption underlies the cognitive deficits seen across a range of neurological and psychiatric conditions. Decades of research have established that frontal-midline theta oscillations (4–8 Hz) are a neural signature of working memory engagement, and that TMS can modulate these rhythms. What has remained elusive is a reliable method to intervene at the precise moment when the brain’s own activity signals the need for support — rather than delivering stimulation on a fixed schedule, regardless of cognitive state. 

Dr. Erickson’s project develops exactly this: a closed-loop TMS system that monitors ongoing frontal-midline theta oscillations in real time via EEG and triggers stimulation precisely when theta activity falls below threshold, providing targeted support at the moment of cognitive demand. This brain-state-contingent approach moves beyond open-loop paradigms — which apply stimulation regardless of neural context — toward a fundamentally more precise and responsive intervention. The study will characterize how real-time, theta-triggered TMS affects working memory performance and underlying neural dynamics, generating the proof-of-concept data needed to pursue larger trials in patient populations for whom working memory failure has devastating functional consequences.