CONTRALATERAL DELAY ACTIVITY REFLECTS ACCELERATED VOLUNTARY REACTIVATION OF MEANINGFUL WORKING MEMORY REPRESENTATIONS

Working memory (WM) representations integrate high-level semantic content with low-level visual features. Prior research suggests that voluntary retrospective attention retrieves WM representations more effectively when they are meaningful rather than meaningless. In this registered retro-cueing EEG study (n=40), we tested whether the contralateral delay activity (CDA) reflects this distinction. WM content (intact vs. scrambled) was manipulated alongside retrocue type (predictive voluntary vs. non-predictive involuntary). Meaningfulness was controlled using diffeomorphic scrambling of real-world images, producing intact stimuli with semantic and visual features and scrambled stimuli preserving low-level visual features. We predicted that voluntary attention would elicit a larger CDA for intact than scrambled stimuli, with no CDA for involuntary attention. Behavioral performance was modeled using a hierarchical drift-diffusion approach, estimating drift rates as an index of representational quality and non-decision times as an index of retrieval speed. Non-decision times showed a voluntary retro-cueing effect larger for intact than scrambled stimuli. Drift rates revealed retro-cueing effects for both cue types, stronger under voluntary attention. Electrophysiologically, a cluster-based analysis across an occipito-parietal region identified a late CDA cluster (1400–1700 ms) for scrambled stimuli under voluntary attention. A follow-up analysis over canonical CDA electrodes revealed an earlier cluster (800–970 ms) exclusively for intact stimuli under voluntary attention. These results indicate that voluntary WM retrieval is facilitated by meaningful content and that intact representations are reactivated earlier than scrambled ones. The findings support a temporal dissociation in the neural dynamics of retrospective attention, suggesting that semantic content accelerates WM reinstatement.