Neuroscience

Prefrontal cortex

Recall

Hippocampal formation

Cognition

Cognitive psychology

Psychology

Mnemonic

Hippocampus

Electroencephalography

Proceedings of the National Academy of Sciences

Significance How do we adaptively switch from perceiving the external world to retrieving goal-relevant internal memories? To tackle this question, we used—in a cued-recall paradigm—direct intracranial recordings from the human hippocampus complemented by high-density scalp electroencephalography (EEG). We found that a hippocampal signal ∼500 ms after a perceptual cue marks the conversion from external (perceptual) to internal (mnemonic) representations. This sets in motion a recall cascade involving posterior parietal and medial prefrontal cortex, revealed via source-localized and time-resolved EEG alpha power. Together, these results unveil the hippocampal–cortical dynamics supporting rapid and flexible memory recall.

The hippocampus as the switchboard between perception and memory