Flexibility and control in working memory gating: behavioral, demographic, and neuromodulatory influences
Embargo Date
2027-05-27
OA Version
Citation
Abstract
Working memory (WM) supports goal-directed behavior by maintaining and updating relevant information. A key mechanism underlying this function is gating—the selective control of what enters and exits WM and how its contents guide behavior. This dissertation investigated how behavioral cues, aging, and neuromodulation influence distinct WM gating operations, leveraging the reference-back task to isolate input, output, and response gating. Chapter 2 examined the effects of retro-cues and aging. Retro-cues enhanced gating efficiency by reducing switch costs and mitigating interference, particularly under high-conflict conditions. These benefits extended to updating processes, suggesting that cue-driven selective reactivation facilitates proactive control across WM functions. In contrast, aging broadly impaired performance, increasing gate switch costs and elevating updating demands. Chapter 3 explored whether a specific gating mechanism—input gate opening—could be selectively modulated via neuromodulation. High-definition transcranial alternating current stimulation (HD-tACS) significantly reduced input gate opening costs without affecting other WM operations or overall task performance. This result supports theoretical accounts of beta oscillations as facilitators of flexible cognitive engagement and highlights their role in WM gating dynamics. Exploratory EEG analyses also implicated delta-band activity during gate opening, suggesting a potential interaction between oscillatory and corticostriatal mechanisms. Together, these findings offer converging evidence that WM gating is a functionally dissociable process shaped by attentional control, neural oscillations, and aging. Behavioral and demographic factors exerted broad effects across WM operations, while frequency-specific neuromodulation selectively influenced a targeted gating mechanism. These insights refine the Prefrontal–Basal Ganglia Working Memory (PBWM) framework and offer promising, non-invasive strategies for improving cognitive control in aging and clinical populations.
Description
2025