Theta-mediated conceptual reinstatement in vmPFC precedes perceptual reinstatement in ventral visual cortex during memory recall

When recalling past episodes, different features of an experience, such as conceptual meaning and perceptual detail, are reconstructed and reinstated across distributed cortical regions. However, current models of human memory remain unclear how these feature-specific reinstatements unfold over time, and whether they interact hierarchically during memory retrieval. Using magnetoencephalography (MEG) and time-resolved encoding-retrieval cross-phase classification analysis, we compared the time course of conceptual and perceptual reinstatement during cued visual recall. Conceptual information decoding in the ventromedial prefrontal cortex (vmPFC) preceded perceptual information decoding in the ventral visual cortex (VVC), and the two were expressed in distinct frequency bands: theta (4-8 Hz) for conceptual and gamma (30-40 Hz) for perceptual information. Cross-correlation and spectral Granger causality analyses revealed that during reinstatement conceptual information in vmPFC predicted and directed perceptual information in VVC, with theta-band information flow predominantly from vmPFC to VVC. In addition, bottom-up connectivity from VVC to vmPFC was expressed in the alpha band. These findings suggest that memory retrieval proceeds from abstract conceptual reconstruction to the reinstatement of perceptual details, mediated by theta oscillatory communication between prefrontal and sensory areas. We propose a hierarchical interactive model in which vmPFC initiates conceptual activation through theta-band top-down signals, while VVC provides alpha-band feedback for evaluating reconstructed perceptual details.