This study investigates the dynamics of frontal midline theta (fmθ) activity during visual working memory. Using independent component analysis (ICA), researchers decomposed EEG data from 71 channels and identified fmθ components associated with theta and low-beta oscillations. These components were found to originate from or near the dorsal anterior cingulate cortex. Theta power in these components varied across trials but correlated with other frontal and temporal processes. During memorized letter trials, fmθ components exhibited low-beta activity (12–15 Hz) stronger than during ignored trials. A 3-Hz burst occurred 500 ms after the probe letter. Log spectral ICA revealed that low-beta activity in fmθ components reflected harmonic theta wave trains and independent bursts. The variability in fmθ activity may reflect dynamic adjustments in medial frontal cortex to task demands. The study also found that fmθ components accounted for most of the memory load-related increases in frontal midline theta power. ERSP analysis showed that theta power increased with memory load, particularly in high-load trials. The fmθ cluster was localized near the dorsal anterior cingulate cortex, and its activity was significantly modulated by memory load. The study highlights the role of fmθ in working memory and its potential as a marker of dynamic cortical adjustments.This study investigates the dynamics of frontal midline theta (fmθ) activity during visual working memory. Using independent component analysis (ICA), researchers decomposed EEG data from 71 channels and identified fmθ components associated with theta and low-beta oscillations. These components were found to originate from or near the dorsal anterior cingulate cortex. Theta power in these components varied across trials but correlated with other frontal and temporal processes. During memorized letter trials, fmθ components exhibited low-beta activity (12–15 Hz) stronger than during ignored trials. A 3-Hz burst occurred 500 ms after the probe letter. Log spectral ICA revealed that low-beta activity in fmθ components reflected harmonic theta wave trains and independent bursts. The variability in fmθ activity may reflect dynamic adjustments in medial frontal cortex to task demands. The study also found that fmθ components accounted for most of the memory load-related increases in frontal midline theta power. ERSP analysis showed that theta power increased with memory load, particularly in high-load trials. The fmθ cluster was localized near the dorsal anterior cingulate cortex, and its activity was significantly modulated by memory load. The study highlights the role of fmθ in working memory and its potential as a marker of dynamic cortical adjustments.