Rapid item-updating elevates neural manifold dynamics during encoding: evidence from a fixed-load verbal working-memory dataset

We analyzed open neuro dataset ds006848, a fixed-load verbal working-memory EEG-ECG-PPG dataset (N = 30), comparing four visual presentation modes. Rapid sequential encoding (Fast, FastDelay) elevated neural manifold mobility (m) and diffusivity (d) during encoding relative to simultaneous or slow-paced display — while recall accuracy showed the opposite ordering. This behavioral dissociation indicates that m/d indexes rapid item-updating demand, not encoding success. Maintenance-period geometry was indistinguishable across conditions (Friedman p = 0.96), confirming the effect is encoding-specific.