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

MITRA, ANISH; SNYDER, ABRAHAM Z.; HACKER, CARL D.; PAHWA, MRINAL; TAGLIAZUCCHI, ENZO; LAUFS, HELMUT; LEUTHARDT, ERIC C.; RAICHLE, MARCUS E.

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

NATL ACAD SCIENCES

Año: 2016 vol. 113 p. 6868 - 6876

0027-8424

Declarative memory consolidation is hypothesized to require a twostage, 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.