Subsequent memory-dependent EEG θ correlates to parahippocampal blood oxygenation level-dependent response

The 4–12 Hz (θ rhythm)-dependent neural dynamics play a fundamental role in the memory formation of the rat hippocampus. Although the power of human scalp electroencephalography θ (EEG θ) is known to be associated with a hippocampus-dependent memory encoding, it remains unclear whether the human hippocampus uses θ rhythm. In this study, we aim to identify the scalp EEG θ-related neural regions during memory encoding by using a simultaneous EEG–functional magnetic resonance imaging recording. We showed that the parahippocampal and the medial frontal and posterior regions were significantly correlated to subsequent memory-dependent EEG θ power. This evidence suggests that the human parahippocampal region and associated structures use θ rhythm during hippocampal memory encoding as in rodents.