Frequency-dependent photic modulation of wakeful consolidation in visual learning

Consolidation of encoded information during both sleep and wakefulness is crucial for learning, yet wakeful consolidation remains largely uncharted. Here, we demonstrate frequency-dependent modulation of the wakeful consolidation of visual learning by repetitive visual stimulation (RVS). Participants were trained on an orientation discrimination task and then exposed to flickering gratings at different temporal frequencies to modulate consolidation. We found that the 10-Hz grating RVS improved subsequent discrimination performance, while the 1-Hz grating RVS impaired it. These modulatory effects disappeared when gratings were replaced with uniform disks in RVS or when training was omitted, suggesting that such effects rely on early-stage sensory processing and reflect the modulation of consolidation, rather than being a direct consequence of RVS itself. Using event-related potentials (ERPs) and magnetic resonance spectroscopy (MRS), we showed that the RVS-facilitated wakeful consolidation manifested as enhanced N1 and increased glutamate/GABA (excitation/inhibition) ratio in the early visual cortex, implying a role of LTP-like plasticity in the modulation. These findings introduce a photic stimulation method for modulating wakeful consolidation, different from behavioral interventions and electrical/magnetic stimulations, and offer insights into the neural mechanisms underlying wakeful consolidation, a long-overlooked stage in learning.