Human cortical-hippocampal dialogue in wake and slow-wave sleep

Proc Natl Acad Sci U S A. 2016 Nov 1;113(44):E6868-E6876. doi: 10.1073/pnas.1607289113. Epub 2016 Oct 17.


Declarative memory consolidation is hypothesized to require a two-stage, reciprocal cortical-hippocampal dialogue. According to this model, higher frequency signals convey information from the cortex to hippocampus during wakefulness, but in the reverse direction during slow-wave sleep (SWS). Conversely, lower-frequency activity propagates from the information "receiver" to the "sender" to coordinate the timing of information transfer. Reversal of sender/receiver roles across wake and SWS implies that higher- and lower-frequency signaling should reverse direction between the cortex and hippocampus. However, direct evidence of such a reversal has been lacking in humans. Here, we use human resting-state fMRI and electrocorticography to demonstrate that δ-band activity and infraslow activity propagate in opposite directions between the hippocampus and cerebral cortex. Moreover, both δ activity and infraslow activity reverse propagation directions between the hippocampus and cerebral cortex across wake and SWS. These findings provide direct evidence for state-dependent reversals in human cortical-hippocampal communication.

Keywords: cortex; dynamics; hippocampus; memory; sleep.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brain Waves / physiology*
  • Cerebral Cortex / physiology*
  • Electroencephalography
  • Hippocampus / physiology*
  • Humans
  • Magnetic Resonance Imaging / methods
  • Memory / physiology
  • Memory Consolidation / physiology
  • Sleep / physiology*
  • Temporal Lobe / physiology
  • Wakefulness / physiology